@article{amankwaah_williamson_reynolds_ibrahem_pecota_zhang_olukolu_truong_carey_felde_et al._2023, title={Development of NIRS calibration curves for sugars in baked sweetpotato}, volume={7}, ISSN={["1097-0010"]}, DOI={10.1002/jsfa.12800}, abstractNote={BACKGROUND
Variability in sugar content between raw and cooked sweetpotato storage roots impact nutritional and dietary importance with implications for consumer preference. High-throughput phenotyping is required to breed varieties that satisfy consumer preferences.


RESULTS
Near-infrared reflectance spectroscopy (NIRS) calibration curves were developed for analyzing sugars in baked storage roots using 147 genotypes from a population segregating for sugar content and other traits. The NIRS prediction curves had high coefficients of determination in calibration (R2 c ) of 0.96 (glucose), 0.93 (fructose), 0.96 (sucrose), and 0.96 (maltose). The corresponding coefficients of determination for cross validation (R2 cv ) were 0.92 (glucose), 0.89 (fructose), 0.96 (sucrose) and 0.93 (maltose) and were similar to the R2 c for all sugars measured. The ratios of the standard deviation of the reference set to the standard error of cross validation were greater than three for all sugars. These results confirm the applicability of the NIRS curves in efficiently determining sugar content in baked sweetpotatoes storage roots. External validation was performed on an additional 70 genotypes. Coefficients of determination (r2 ) were 0.88 (glucose), 0.88 (fructose), 0.86 (sucrose) and 0.49 (maltose). The results were comparable to those found for the calibration and cross validation in fructose, glucose, and sucrose, but were moderate for maltose due to the low variability of maltose content in the population.


CONCLUSIONS
NIRS can be used for screening sugar content in baked sweetpotato storage roots in breeding programs and can be used to assist with the development of improved sweetpotato varieties that better meet consumer preferences. This article is protected by copyright. All rights reserved.}, journal={JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE}, author={Amankwaah, Victor A. and Williamson, Sharon and Reynolds, Rong and Ibrahem, Ragy and Pecota, Kenneth V. and Zhang, Xiaofei and Olukolu, Bode A. and Truong, Van-Den and Carey, Edward and Felde, Thomas Zum and et al.}, year={2023}, month={Jul} }
 @article{amankwaah_williamson_olukolu_truong_carey_ssali_yencho_2023, title={Interrelations of & alpha;- and & beta;-amylase activity with starch, sugars, and culinary and nutritional quality attributes in sweetpotato storage roots}, volume={7}, ISSN={["1097-0010"]}, url={https://doi.org/10.1002/jsfa.12832}, DOI={10.1002/jsfa.12832}, abstractNote={BACKGROUND
Little information is available on α- and β-amylase activity and their associations with starch, sugars and other culinary qualities in sweetpotato. The objective of this study was to assess sweetpotato storage root α- and β-amylase activity in relation to starch, sugars, β-carotene content and storage root flesh color.


RESULTS
α- and β-amylase activity (α-AA and β-AA) were assayed from a Tanzania (T) x Beauregard (B) genetic mapping population in their uncured (raw), cured and stored (~ 11 weeks) forms during 2016 and 2017. The Ceralpha and Betamyl methods, with modifications to suit a high-throughput microplate assay format, were used to quantify α-AA and β-AA, respectively. Storage root dry matter, starch, glucose, fructose, sucrose, and β-carotene content were predicted using near infrared reflectance spectroscopy (NIRS). There was little relationship (r2  = 0.02-0.08, p-value ≤0.05 in 2016 and r2  = 0.05-0.11, p-value ≤0.05 in 2017) between α-AA and β-AA. We observed negative linear associations between α-AA and dry matter content and generally no correlations between β-AA and dry matter content. β-AA and sugars were weakly positively correlated. β-AA and β-carotene content were positively correlated (r = 0.3-0.4 in 2016 and 0.3-0.5 in 2017).


CONCLUSIONS
Generally, the correlation coefficient for amylase enzyme activity and sugar components of storage roots at harvest increased after curing and during post-harvest storage. This study is a major step forward in sweetpotato breeding by providing a better understanding of how α- and β-amylase activity are inter-associated with several culinary quality attributes. This article is protected by copyright. All rights reserved.}, journal={JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE}, author={Amankwaah, Victor A. A. and Williamson, Sharon and Olukolu, Bode A. A. and Truong, Van-Den and Carey, Edward and Ssali, Reuben and Yencho, George Craig}, year={2023}, month={Jul} }
 @article{allan_marinos_johanningsmeier_sato_truong_2021, title={Relationships between isolated sweetpotato starch properties and textural attributes of sweetpotato French fries}, volume={86}, ISSN={["1750-3841"]}, DOI={10.1111/1750-3841.15725}, abstractNote={Sweetpotato French fry (SPFF) textures have been associated with dry matter and starch contents, but these do not fully account for all textural differences. This study investigated the relationships between the physicochemical properties of sweetpotato starch and textural attributes of sweetpotato fries. Starches from 16 sweetpotato genotypes that varied in dry matter content were isolated and analyzed. The amylose content, pasting temperatures and viscosities, and textural properties of equilibrated starch gels were measured. Correlational analysis was performed with the respective SPFF mechanical and sensory texture attributes. Sweetpotato starch amylose content ranged from 17.3% to 21.1%, and the pasting and gel textural properties varied significantly between starches. Starch from orange-fleshed sweetpotatoes had lower pasting temperatures than starches from yellow/cream-fleshed genotypes, 72.2 ± 2.0 and 75.5 ± 1.1 °C, respectively. Notable inverse correlations were observed between the starch pasting temperature and perceived moistness (r = -0.63) and fibrousness (r = -0.70) of fries, whereas SPFF denseness was positively associated with starch pasting viscosity (r = 0.60) and nonstarch alcohol-insoluble solids content. Fry textures were likely affected by cooked starch properties, which should be considered when selecting varieties for sweetpotato fries. PRACTICAL APPLICATION: Without the aid of a batter, sweetpotato French fries (SPFFs) tend to be soft and limp-undesirable attributes in a fried food. The physiochemical properties of starch, the most abundant component in sweetpotato fries, were further explored in this study to better understand the properties of sweetpotato starch that influence SPFF textures. These findings can be used by sweetpotato processors and breeders for developing new sweetpotato varieties that are designed for production of fried products with desirable textures.}, number={5}, journal={JOURNAL OF FOOD SCIENCE}, author={Allan, Matthew C. and Marinos, Nicholas and Johanningsmeier, Suzanne D. and Sato, Ai and Truong, Van-Den}, year={2021}, month={May}, pages={1819–1834} }
 @article{qiu_reynolds_johanningsmeier_truong_2020, title={Determination of free amino acids in five commercial sweetpotato cultivars by hydrophilic interaction liquid chromatography-mass spectrometry}, volume={92}, ISSN={["1096-0481"]}, DOI={10.1016/j.jfca.2020.103522}, abstractNote={A sensitive and rapid method was developed for the determination of free amino acid profiles in sweetpotatoes. The method utilized an ultra-high-performance liquid chromatography system with hydrophilic interaction liquid chromatography (HILIC) separation coupled with tandem mass-spectrometry (MS/MS) detection without the need for chemical derivatization. Separation of 36 amino acid standards was achieved on a silica HILIC column in a single MS/MS run of 19 min. This validated method was applied for the analysis of the free amino acid composition of five commercial sweetpotato cultivars (Covington, Beauregard, Hatteras, Murasaki-29 and O’ Henry) from two planting lots grown in experimental fields. Analysis of variance with Tukey’s test was used to determine the differences in individual free amino acid content among the analyzed samples, and principle component analysis (PCA) was implemented to evaluate the variation in amino acid profiles of different sweetpotato cultivars. Asparagine was the most abundant free amino acid and its content varied significantly among the cultivars (p < 0.05). Fifteen additional amino acids also varied among cultivars and contributed to the differentiation of the genotypes by PCA based on their complete amino acid profiles. The efficient, reliable, sensitive method described herein could be used in quantifying amino acids in food matrices similar to sweetpotatoes.}, journal={JOURNAL OF FOOD COMPOSITION AND ANALYSIS}, author={Qiu, Xiao and Reynolds, Rong and Johanningsmeier, Suzanne and Truong, Van-Den}, year={2020}, month={Sep} }
 @article{truong_thor_harris_simunovic_truong_2019, title={Acid Inhibition on Polyphenol Oxidase and Peroxidase in Processing of Anthocyanin-Rich Juice and Co-product Recovery from Purple-Fleshed Sweetpotatoes}, volume={84}, ISSN={["1750-3841"]}, DOI={10.1111/1750-3841.14664}, abstractNote={AbstractWith high phytochemical and starch contents, purple‐fleshed sweetpotatoes (PFSP) have been processed into various functional ingredients and food products including juices and natural colorants. For juice processing, PFSP are usually subjected to heat treatment for inactivation of pigment‐degrading enzymes. However, heating of sweetpotatoes gelatinizes starch and produces thick slurry with cooked flavor, which are the drawbacks. Development of alternative processes to overcome the stated problems will be beneficial to sweetpotato processors. This study demonstrated that acidified water (≥3% w/v citric acid) was effective in inhibiting polyphenol oxidase and peroxidase in raw PFSP resulting in an attractive reddish juice. About 93% total phenolics (TP) and 83% total monomeric anthocyanins (TMA) in PFSP were extracted by two repeated extractions. The combined PFSP juice (3.2 L/kg PFSP) had high levels of TP (1,850 mg/L) and TMA (475 mg/L). With the developed process, 167 g dried starch, and 140 g dried high‐fiber pomace were obtained for each kg raw PFSP, besides the highly pigmented juice. Pasteurization of the PFSP juice samples (pH 3.2) at 80 °C for 12 s resulted in 15% loss in TMA and had no effect on TP. The results indicated an efficient process to produce sweetpotato juice with high bioactive compounds and recovery of starch and high dietary fiber pomace as co‐products.}, number={7}, journal={JOURNAL OF FOOD SCIENCE}, author={Truong, An N. and Thor, Yiwen and Harris, G. Keith and Simunovic, Josip and Truong, Van-Den}, year={2019}, month={Jul}, pages={1730–1736} }
 @article{chilungo_muzhingi_truong_allen_2019, title={Effect of processing and oil type on carotene bioaccessibility in traditional foods prepared with flour and puree from orange-fleshed sweetpotatoes}, volume={54}, ISSN={["1365-2621"]}, DOI={10.1111/ijfs.14106}, abstractNote={Summary}, number={6}, journal={INTERNATIONAL JOURNAL OF FOOD SCIENCE AND TECHNOLOGY}, author={Chilungo, Sarah and Muzhingi, Tawanda and Truong, Van-Den and Allen, Jonathan C.}, year={2019}, month={Jun}, pages={2055–2063} }
 @article{ding_johanningsmeier_price_reynolds_truong_payton_breidt_2018, title={Evaluation of nitrate and nitrite contents in pickled fruit and vegetable products}, volume={90}, ISSN={["1873-7129"]}, DOI={10.1016/j.foodcont.2018.03.005}, abstractNote={Our objective was to investigate nitrate and nitrite contents of acidified and fermented fruits and vegetables. l-ascorbic acid and total phenols were also examined based on the hypothesis that the presence of these antioxidant compounds may influence N-nitrosation reactions upon human consumption. The fermented and acidified vegetable products included 131 samples from multiple lots of 46 different commercially available products. Nitrite was detected in low concentrations (<1.5 mg/100 g) in four acidified (pickled green beans, red cabbage, pickled beets, and pickled mushrooms) and two fermented products (Greek olives and kimchi). Nitrate concentrations ranged from a mean value of 122 mg/100 g for kimchi to undetectable levels in acidified Brussels sprouts. Measures of antioxidant compounds showed that artichoke hearts had the highest total polyphenols (225 mg/100 g), and olive products had between 84 ± 5 mg/100 g (Spanish table olives) and 170 ± 8 mg/100 g (Greek olives). An acidified red pepper product had the highest l-ascorbic acid content of 32 ± 10 mg/100 g, with a low nitrate level of 0.1 ± 0.09 mg/100 g. These results provide new information for evaluating nitrate and nitrite contents in pickled fruit and vegetable products with regard to potential human dietary health consequences.}, journal={FOOD CONTROL}, author={Ding, Zhansheng and Johanningsmeier, Suzanne D. and Price, Robert and Reynolds, Rong and Truong, Van-Den and Payton, Summer Conley and Breidt, Fred}, year={2018}, month={Aug}, pages={304–311} }
 @article{sato_truong_johanningsmeier_reynolds_pecota_yencho_2017, title={Chemical Constituents of Sweetpotato Genotypes in Relation to Textural Characteristics of Processed French Fries}, volume={83}, ISSN={0022-1147}, url={http://dx.doi.org/10.1111/1750-3841.13978}, DOI={10.1111/1750-3841.13978}, abstractNote={AbstractSweetpotato French fries (SPFF) are growing in popularity, however limited information is available on SPFF textural properties in relation to chemical composition. This study investigated the relationship between chemical components of different sweetpotato varieties and textural characteristics of SPFF. Sixteen sweetpotato genotypes were evaluated for (1) chemical constituents; (2) instrumental and sensory textural properties of SPFF; and (3) the relationship between chemical components, instrumental measurements, and sensory attributes. Dry matter (DM), alcohol‐insoluble solids (AIS), starch, sugar, and oil content, and also α‐ and β‐amylase activities were quantified in raw sweetpotatoes and SPFF. Peak force and overall hardness describing instrumental textural properties of SPFF were measured using a texture analyzer. Descriptive sensory analysis was conducted and 10 attributes were evaluated by a trained panel. Results showed that DM, AIS, and starch content in raw sweetpotatoes were significantly correlated (P < 0.05) with instrumental peak force and overall hardness (r = 0.41 to 0.68), and with sensory surface roughness, hardness, fracturability, and crispness (r = 0.63 to 0.90). Total sugar content in raw sweetpotatoes was positively correlated with sensory smoothness and moistness (r = 0.77), and negatively correlated with instrumental peak force and overall hardness (r = –0.62 to –0.69). Instrumental measurements were positively correlated with sensory attributes of hardness, fracturability, and crispness (r = 0.68 to 0.96) and negatively correlated with oiliness, smoothness, moistness, and cohesiveness (r = –0.61 to –0.91). Therefore, DM, AIS, starch, and total sugar contents and instrumental measurements could be used as indicators to evaluate sweetpotato genotypes for SPFF processing.}, number={1}, journal={Journal of Food Science}, publisher={Wiley}, author={Sato, Ai and Truong, Van-Den and Johanningsmeier, Suzanne D. and Reynolds, Rong and Pecota, Kenneth V. and Yencho, G. Craig}, year={2017}, month={Nov}, pages={60–73} }
 @article{barkley_schultheis_chaudhari_johanningsmeier_jennings_truong_monks_2017, title={Yield and Consumer Acceptability of 'Evangeline' Sweetpotato for Production in North Carolina}, volume={27}, ISSN={["1943-7714"]}, DOI={10.21273/horttech03533-16}, abstractNote={Studies were conducted in 2012 and 2013 to compare Evangeline to various sweetpotato (Ipomoea batatas) varieties (Bayou Belle, Beauregard, Bonita, Covington, NC05-198, and Orleans) for commercial production in North Carolina. In another study, microwaved and oven-baked ‘Evangeline’ and ‘Covington’ sweetpotato roots were subjected to analysis of chemical and physical properties [color, dry matter (DM), texture, and sugar] and to sensory evaluation for determining consumer acceptance. ‘NC05-198’ produced the highest no. 1 grade sweetpotato 600 bushels [bu (50 lb)] per acre and total marketable storage root yield was similar to ‘Bayou Belle’ and ‘Beauregard’ (841, 775, and 759 bu/acre, respectively). No. 1 and marketable root yields were similar between ‘Orleans’ and ‘Beauregard’. However, ‘Orleans’ produced more uniform roots than ‘Beauregard’, in which the latter had higher cull production. ‘Evangeline’ was comparable to no. 1 yield of ‘Bayou Belle’, ‘Orleans’, and ‘Covington’, which indicates the ability of this variety to produce acceptable yields in North Carolina conditions. ‘Covington’ had slightly higher DM than ‘Evangeline’, but instrumental texture analysis showed that these varieties did not differ significantly in firmness after cooking. However, microwaved roots were measurably firmer than oven-baked roots for both varieties. In this study, ‘Evangeline’ had higher levels of fructose and glucose, with similar levels of sucrose and maltose to ‘Covington’. Consumers (n = 100) indicated no difference between varieties in their “just about right” moisture level, texture, and flavor ratings, but showed a preference for Evangeline flesh color over Covington. Consumers in this study preferred oven-baked over microwaved sweetpotato (regardless of variety) and indicated that Evangeline is as acceptable as the standard variety Covington when grown in the North Carolina environment.}, number={2}, journal={HORTTECHNOLOGY}, author={Barkley, Susan L. and Schultheis, Jonathan R. and Chaudhari, Sushila and Johanningsmeier, Suzanne D. and Jennings, Katherine M. and Truong, Van-Den and Monks, David W.}, year={2017}, month={Apr}, pages={281–290} }
 @article{grace_truong_truong_raskin_lila_2015, title={Novel value-added uses for sweet potato juice and flour in polyphenol- and protein-enriched functional food ingredients}, volume={3}, ISSN={["2048-7177"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85010310678&partnerID=MN8TOARS}, DOI={10.1002/fsn3.234}, abstractNote={Abstract}, number={5}, journal={FOOD SCIENCE & NUTRITION}, author={Grace, Mary H. and Truong, An N. and Truong, Van-Den and Raskin, Ilya and Lila, Mary Ann}, year={2015}, month={Sep}, pages={415–424} }
 @article{grace_yousef_gustafson_truong_yencho_lila_2014, title={Phytochemical changes in phenolics, anthocyanins, ascorbic acid, and carotenoids associated with sweetpotato storage and impacts on bioactive properties}, volume={145}, ISSN={["1873-7072"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84884340315&partnerID=MN8TOARS}, DOI={10.1016/j.foodchem.2013.08.107}, abstractNote={Sweetpotato phytochemical content was evaluated in four genotypes (NCPUR06-020, Covington, Yellow Covington, and NC07-847) at harvest and after curing/storage for 4 or 8 months. Curing and storage for up to 8 months did not significantly affect total phenolic content in Covington, Yellow Covington, and NC07-847, however for NCPUR06-020, a purple-fleshed selection, total phenolic content declined mainly due to anthocyanin degradation during storage. Covington had the highest carotenoid content at harvest time (281.9 μg/g DM), followed by NC07-847 (26.2 μg/g DM), and after 8 months, total carotenoids had increased by 25% and 50%, respectively. Antioxidant activity gradually declined during storage, and freshly harvested sweetpotatoes also demonstrated higher anti-inflammatory capacity as gauged by inhibition of lipopolysaccharide-induced reactive oxygen species (ROS) in SH-SY5Y cells. Gradual changes in sweetpotato phytochemical content and antioxidant and anti-inflammatory capacity were noted during normal long-term storage, but the specific effects were genotype-dependent.}, journal={FOOD CHEMISTRY}, publisher={Elsevier BV}, author={Grace, Mary H. and Yousef, Gad G. and Gustafson, Sally J. and Truong, Van-Den and Yencho, G. Craig and Lila, Mary Ann}, year={2014}, month={Feb}, pages={717–724} }
 @article{truong_pascua_reynolds_thompson_palazoglu_mogol_gokmen_2014, title={Processing Treatments for Mitigating Acrylamide Formation in Sweetpotato French Fries}, volume={62}, ISSN={["1520-5118"]}, DOI={10.1021/jf404290v}, abstractNote={Acrylamide formation in sweetpotato French fries (SPFF) is likely a potential health concern as there is an increasing demand for good-quality fries from carotene-rich sweetpotatoes (SP). This is the first report on acrylamide formation in SPFF as affected by processing methods. Acrylamide levels in SPFF from untreated SP strips fried at 165 °C for 2, 3, and 5 min were 124.9, 255.5, and 452.0 ng/g fresh weight, which were reduced by about 7 times to 16.3, 36.9, and 58.3 ng/g, respectively, when the strips were subjected to processing that included water blanching and soaking in 0.5% sodium acid pyrophosphate before frying. An additional step of strip soaking in 0.4% calcium chloride solution before par-frying increased the calcium content from 0.2 to 0.8 mg/g and decreased the acrylamide levels to 6.3, 17.6, and 35.4 ng/g, respectively. SPFF with acrylamide level of <100 ng/g or several times lower than that of white potato French fries can be obtained by integrating processing treatments commonly used in the food industry.}, number={1}, journal={JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY}, author={Truong, Van-Den and Pascua, Yvette T. and Reynolds, Rong and Thompson, Roger L. and Palazoglu, T. Koray and Mogol, Burce Atac and Gokmen, Vural}, year={2014}, month={Jan}, pages={310–316} }
 @article{diaz_chinn_truong_2014, title={Simultaneous saccharification and fermentation of industrial sweetpotatoes for ethanol production and anthocyanins extraction}, volume={62}, ISSN={["1872-633X"]}, DOI={10.1016/j.indcrop.2014.07.032}, abstractNote={A simultaneous saccharification fermentation (SSF) system was studied for ethanol production in flour industrial sweetpotato (ISP) feedstocks (lines: white DM02-180 and purple NC-413) as an integrated cost saving process, and to examine the feasibility of extracting anthocyanins from flour purple ISPs under a simultaneous extraction and fermentation (SEF) system. Furthermore, a separate hydrolysis fermentation (SHF) configuration was carried out to establish a baseline in sugar consumption and ethanol production from the ISP lines. The thermotolerant ethanol producing yeast strain Kluyveromyces marxianus NCYC 851 and the mesophilic Saccharomyces cerevisiae Ethanol Red were evaluated, using commercial alpha amylases for hydrolysis of available ISP starch to sugars. Fermentation by S. cerevisiae during SHF had an ethanol yield of 0.32 g/g dry ISP, a 1.1-fold increase above that produced by K. marxianus. Subsequent studies showed that ethanol yield could be increased in a SSF system with a maximum ethanol yield of 0.39 g/g dry ISP achieved, a 15% increase compared with using a SHF system when S. cerevisiae was used. Simultaneous extraction and fermentation of flour purple-fleshed NC-413 ISPs was studied to evaluate the effect of pH on extraction of total monomeric anthocyanins (TMA) and ethanol production. On average, maximum ethanol yield ranged from 0.31 to 0.34 g/g dry ISP and TMA concentration ranged from 45 to 64 mg cyanidin-3-glu/100 g dry powder (10–22 mg/100 g fresh weight) with the greatest ethanol production coming from non-adjusted pH fermentations. The highest anthocyanin recovery, 64 mg cyanidin-3-glu/100 g dry powder was obtained at 35 °C and pH 4.5 using S. cerevisiae Ethanol Red. This study showed the feasibility of extracting anthocyanins and producing ethanol simultaneously in one unit operation without the need of purified solvents.}, journal={INDUSTRIAL CROPS AND PRODUCTS}, author={Diaz, Joscelin T. and Chinn, Mari S. and Truong, Van-Den}, year={2014}, month={Dec}, pages={53–60} }
 @article{adu-kwarteng_sakyi-dawson_ayernor_truong_shih_daigle_2014, title={VARIABILITY OF SUGARS IN STAPLE-TYPE SWEET POTATO (IPOMOEA BATATAS) CULTIVARS: THE EFFECTS OF HARVEST TIME AND STORAGE}, volume={17}, ISSN={["1094-2912"]}, DOI={10.1080/10942912.2011.642439}, abstractNote={Total soluble sugar content and composition was studied by high performance liquid chromatography in four high dry-matter sweet potato cultivars at 3, 4, and 5 months maturity. Total soluble sugar consisted of sucrose, glucose, and fructose, ranging from 4.10–10.82 g/100 g (dry-weight basis). At harvest, there were significant differences in total soluble sugar due to maturity (p < 0.001) and cultivar (p < 0.05). The highest total soluble sugar contents were in 5-month samples at harvest (7.36–10.34 g/100 g) and 4-month samples after short-term storage under tropical ambient conditions (8.66–10.82 g/100 g). Estimated amylase enzyme activity varied significantly with harvest age (p < 0.05). Although reducing sugar contents were low, fructose levels in 5-month samples increased considerably after storage.}, number={2}, journal={INTERNATIONAL JOURNAL OF FOOD PROPERTIES}, author={Adu-Kwarteng, Evelyn and Sakyi-Dawson, Esther O. and Ayernor, George S. and Truong, Van-Den and Shih, Fred F. and Daigle, Kim}, year={2014}, month={Feb}, pages={410–420} }
 @article{koskiniemi_truong_mcfeeters_simunovic_2013, title={Effects of Acid, Salt, and Soaking Time on the Dielectric Properties of Acidified Vegetables}, volume={16}, ISSN={["1532-2386"]}, DOI={10.1080/10942912.2011.567428}, abstractNote={In order to design a continuous microwave process for pasteurization of acidified vegetables, equilibration phenomena in acid and salt solutions must be examined with regards to changes in dielectric properties. The objective of this study was to examine the effects of acid and salt concentration on the dielectric properties of acidified vegetables. Broccoli florets and sweet potato cubes (1.2 cm) were blanched to facilitate acid and salt equilibration by heating for 15 s in boiling de-ionized water. Red bell pepper cubes were not blanched. The vegetable samples were then acidified in solutions of 1–2% sodium chloride with 0.5–2% citric acid. Dielectric properties were measured at 915 MHz from 25 to 100°C after 0-, 4-, and 24-h soaking periods in the solutions using an open-ended coaxial probe connected to a network analyzer. Equilibration occurred within 4 h of salting and acidification. Acid and salt concentration had no significant effect on the dielectric constant (ϵ′). However, ϵ′ was significantly different among vegetables (p < 0.05). Dielectric loss factor (ϵ″) was not affected by acid, but significantly increased with salt concentration. These results provide necessary dielectric property information to apply microwave heating technology in processing of acidified vegetables.}, number={4}, journal={INTERNATIONAL JOURNAL OF FOOD PROPERTIES}, author={Koskiniemi, Craig B. and Truong, Van-Den and McFeeters, Roger F. and Simunovic, Josip}, year={2013}, month={May}, pages={917–927} }
 @article{koskiniemi_truong_mcfeeters_simunovic_2013, title={Quality evaluation of packaged acidified vegetables subjected to continuous microwave pasteurization}, volume={54}, ISSN={["1096-1127"]}, DOI={10.1016/j.lwt.2013.04.016}, abstractNote={The study evaluated the use of 915 MHz continuous microwave processing with a rotation apparatus for pasteurization of acidified vegetable packages. Broccoli florets, and 1.2 cm cubes of broccoli stems, red bell pepper, and sweetpotato were pre-equilibrated to 1 g/100 g NaCl and 0.38 g/100 mL citric acid, and separately placed in 110 mL cups with a 0.5 g/100 mL citric acid solution. Unsealed packages were placed on a conveyor belt and run through a 915 MHz microwave cavity operating at 3.5 kW (residence time = 4 min). After processing, cups were sealed with a lidding film, and held in insulating molds for 30 min. Infrared thermocouples, fiber optic temperature sensors, and infrared imaging were used to monitor product temperatures. Microbial stability and changes in color and instrumental textural properties were measured over a 60-day storage period at 30 °C. Good retention of color and texture of acidified vegetable pieces was observed after microwave pasteurization. Over storage, textural properties significantly degraded for all vegetables, but the brilliant color of red bell pepper and sweetpotato was relatively retained. Chemical indicators of microbial spoilage were not detected at the end of storage. This study demonstrates a successful continuous microwave pasteurization process for producing shelf-stable acidified vegetable packages.}, number={1}, journal={LWT-FOOD SCIENCE AND TECHNOLOGY}, author={Koskiniemi, Craig B. and Truong, Van-Den and McFeeters, Roger F. and Simunovic, Josip}, year={2013}, month={Nov}, pages={157–164} }
 @article{maloney_truong_allen_2012, title={Chemical Optimization of Protein Extraction from Sweet Potato (Ipomoea batatas) Peel}, volume={77}, ISSN={["1750-3841"]}, DOI={10.1111/j.1750-3841.2012.02921.x}, abstractNote={Abstract:  Proteins isolated from sweet potatoes (Ipomoea batatas) have been shown to possess antidiabetic, antioxidant, and antiproliferative properties. The objective of this study was to chemically optimize a process for extracting proteins from sweet potato peel. The extraction procedure involved mixing peel with saline solvent to dissolve proteins and then precipitating with CaCl2. Quadratic and segmented models were used to determine the optimum NaCl concentration and peel to solvent ratio to maximize protein solubility while minimizing solvent usage. A segmented model was also used to optimize the concentration of CaCl2 used for precipitation. The highest yield was obtained by mixing blanched peelings with 59.7 mL of 0.025 mM NaCl per g peel and then precipitating with 6.8 mM CaCl2. The results of this study show that potentially valuable proteins can be extracted from peel generated during processing of sweet potatoes and industrial costs can be minimized by using these optimum conditions.}, number={11}, journal={JOURNAL OF FOOD SCIENCE}, author={Maloney, Katherine P. and Truong, Van-Den and Allen, Jonathan C.}, year={2012}, month={Nov}, pages={E307–E312} }
 @article{truong_hu_thompson_yencho_pecota_2012, title={Pressurized liquid extraction and quantification of anthocyanins in purple-fleshed sweet potato genotypes}, volume={26}, ISSN={["1096-0481"]}, DOI={10.1016/j.jfca.2012.03.006}, abstractNote={Analysis of anthocyanins responsible for the purple flesh color is important for breeding programs and development of value-added products. This study aimed to optimize the conditions for anthocyanin extraction from purple-fleshed sweet potatoes (PFSP) using pressurized-liquid extraction (PLE) method and quantify anthocyanins in various genotypes. Freeze-dried powders of PFSP genotypes were extracted with acidified methanol using an accelerated solvent extractor. Anthocyanin content of the extract was characterized by (a) pH-differential method and (b) color value protocol measuring absorbance at 530 nm, which is commonly used in Japan as a commercial indicator of total anthocyanin quantity. Highest anthocyanin yields by PLE were with an acetic acid:methanol:water mixture of 7:75:18% (v/v), sample weight of <0.5 g and 80–120 °C. Among 335 genotypes, the anthocyanin content varied widely from 0 to 663 mg cyanidine-3-glucoside equivalent/100 g powder or 0–210 mg/100 g fresh weight. The total monomeric anthocyanin (TMA) contents determined by the pH-differential method were highly correlated with the Japan color value (JCV) protocol, TMA = (0.145) JCV, R2 = 0.943. These results can be useful for sweet potato breeding programs and processing industry in development of PFSP cultivars and processed products with high anthocyanin levels.}, number={1-2}, journal={JOURNAL OF FOOD COMPOSITION AND ANALYSIS}, publisher={Elsevier BV}, author={Truong, V. D. and Hu, Z. and Thompson, R. L. and Yencho, G. C. and Pecota, K. V.}, year={2012}, pages={96–103} }
 @article{leksrisompong_whitson_truong_drake_2012, title={SENSORY ATTRIBUTES AND CONSUMER ACCEPTANCE OF SWEET POTATO CULTIVARS WITH VARYING FLESH COLORS}, volume={27}, ISSN={["1745-459X"]}, DOI={10.1111/j.1745-459x.2011.00367.x}, abstractNote={ABSTRACTThe sensory characteristics of sweet potatoes (n = 12 cultivars) with varying flesh color (orange, purple, yellow) and the impact of flesh colors on consumer acceptance were evaluated. A lexicon was developed for sweet potato flavor followed by consumer acceptance testing conducted with and without blindfold conditions to identify if color or visual cues impacted consumer acceptance. Cluster analysis was performed on overall liking scores followed by external preference mapping to identify the drivers of liking for sweet potatoes. The lexicon differentiated sweet potatoes. Appearance (visual appearance) positively impacted liking scores of products that were not well liked but had a lower impact on liking when the sweet potato was well liked suggesting that flavor and texture were the driving attributes for liking. Three consumer clusters were found for overall liking. All clusters liked smooth texture, brown sugar and dried apricot flavor and sweet taste and disliked bitter, umami, astringent mouthfeel, vanilla aroma and residual fibers. Clusters were differentiated by the liking of visual moistness and color homogeneity, white potato, canned carrot and dried apricot flavors, chalky, firmness, denseness and fibrous texture. Sweet potatoes with unfamiliar colors were accepted by all consumers but different sensory characteristics appealed to different consumer groups.}, number={1}, journal={JOURNAL OF SENSORY STUDIES}, author={Leksrisompong, P. P. and Whitson, M. E. and Truong, V. D. and Drake, M. A.}, year={2012}, month={Feb}, pages={59–69} }
 @misc{kumar_sandeep_alavi_truong_2011, title={A Review of Experimental and Modeling Techniques to Determine Properties of Biopolymer-Based Nanocomposites}, volume={76}, ISSN={["1750-3841"]}, DOI={10.1111/j.1750-3841.2010.01919.x}, abstractNote={Abstract: The nonbiodegradable and nonrenewable nature of plastic packaging has led to a renewed interest in packaging materials based on bio‐nanocomposites (biopolymer matrix reinforced with nanoparticles such as layered silicates). One of the reasons for unique properties of bio‐nanocomposites is the difference in physics at nanoscale as compared to that at macroscale. Therefore, the effect of nanoscale on the properties of bio‐nanocomposites is discussed. Properties of bio‐nanocomposites are governed by the extent of dispersion of nanoparticles in the biopolymer matrix and interaction between nanoparticles and the biopolymer. Selection of proper technique to determine properties of these bio‐nanocomposites is very critical in assessing their performance. Experimental techniques (tensile testing, barrier property measurement, dynamic mechanical analysis, differential scanning calorimetry, thermogravimetric analysis, rheological measurement) to determine the mechanical, barrier, thermal, and rheological properties of bio‐nanocomposites are discussed in terms of methodology, interpretation of results, and application in studying the properties of bio‐nanocomposites. Mathematical modeling plays an important role in predicting the properties of bio‐nanocomposites and comparing them to the measured properties. This comparison helps in better understanding the mechanism for much improved properties of bio‐nanocomposites. Mathematical modeling is also helpful in understanding the effects of different parameters on the properties of bio‐nanocomposites. Therefore, the article describes mathematical modeling of mechanical and barrier properties of bio‐nanocomposites using analytical micromechanics.}, number={1}, journal={JOURNAL OF FOOD SCIENCE}, author={Kumar, P. and Sandeep, K. P. and Alavi, S. and Truong, V. D.}, year={2011}, pages={E2–E14} }
 @article{cervantes-flores_sosinski_pecota_mwanga_catignani_truong_watkins_ulmer_yencho_2011, title={Identification of quantitative trait loci for dry-matter, starch, and beta-carotene content in sweetpotato}, volume={28}, ISSN={["1380-3743"]}, DOI={10.1007/s11032-010-9474-5}, number={2}, journal={MOLECULAR BREEDING}, publisher={Springer Nature}, author={Cervantes-Flores, J. C. and Sosinski, B. and Pecota, K. V. and Mwanga, R. O. M. and Catignani, G. L. and Truong, V. D. and Watkins, R. H. and Ulmer, M. R. and Yencho, G. C.}, year={2011}, month={Aug}, pages={201–216} }
 @article{koskiniemi_truong_simunovic_mcfeeters_2011, title={Improvement of heating uniformity in packaged acidified vegetables pasteurized with a 915MHz continuous microwave system}, volume={105}, ISSN={0260-8774}, url={http://dx.doi.org/10.1016/j.jfoodeng.2011.02.019}, DOI={10.1016/j.jfoodeng.2011.02.019}, abstractNote={Continuous microwave processing to produce shelf-stable acidified vegetables with moderate to high salt contents poses challenges in pasteurization due to reduced microwave penetration depths and non-uniform heating. Cups of sweetpotato, red bell pepper, and broccoli acidified to pH 3.8 with citric acid solution containing 0–1% NaCl were placed on a conveyor belt and passed through a microwave tunnel operating at 915 MHz and 4 kW with a 4 min residence time. The time–temperature profiles of vegetable pieces at 5 locations in the package were measured using fiber optic temperature sensors. Addition of 1% NaCl to the cover solution lowered microwave penetration into vegetable pieces and decreased the mean temperature in cups of acidified vegetables from 84 to 73 °C. Soaking blanched vegetables for 24 h in a solution with NaCl and citric acid prior to processing improved microwave heating. Heating was non-uniform in all packages with a cold spot of approximately 60 °C at a point in the container farthest from the incident microwaves. More uniform heating was achieved by implementation of a two-stage rotation apparatus to rotate vegetable cups 180° during processing. Rotating the cups resulted in more uniform heating and a temperature of 77 °C at the cold spot. This is above the industrial standard of 74 °C for in-pack pasteurization of acidified vegetables. The effective treatment involved blanching, soaking for 24 h in a NaCl and citric acid solution, and 180° rotation. This work has contributed to a better understanding of the influence of salt addition and distribution during dielectric heating of acidified vegetables using a 915 MHz continuous microwave system.}, number={1}, journal={Journal of Food Engineering}, publisher={Elsevier BV}, author={Koskiniemi, Craig B. and Truong, Van-Den and Simunovic, Josip and McFeeters, Roger F.}, year={2011}, month={Jul}, pages={149–160} }
 @article{bridgers_chinn_truong_2010, title={Extraction of anthocyanins from industrial purple-fleshed sweetpotatoes and enzymatic hydrolysis of residues for fermentable sugars}, volume={32}, ISSN={["1872-633X"]}, DOI={10.1016/j.indcrop.2010.07.020}, abstractNote={Recent trends in health and wellness as well as fossil fuel dependent markets provide opportunities for agricultural crops as renewable resources in partial replacement of synthetic components in food, clothing and fuels. This investigation focused on purple-fleshed industrial sweetpotatoes (ISPs), a crop which is used for industrial purposes because it produces relatively high quantities of antioxidants in the form of anthocyanins as well as high starch content for potential hydrolysis into fermentable sugars. Laboratory extraction and enzymatic hydrolysis studies were conducted on purple-fleshed ISPs in order to evaluate the effects of solvent, extraction temperature and solid loading on recovery of anthocyanins and fermentable sugars. Total monomeric anthocyanin and phenolic concentrations of the extracts were measured. Residual solids from anthocyanin extraction were subsequently hydrolyzed for sugar production (maltotriose, maltose, glucose and fructose). Extraction temperature of 80 °C using acidified methanol at 3.3% (w/v) solid loading showed the highest anthocyanin recovery at 186.1 mg cyanidin-3-glucoside/100 g fw. Acidified solvents resulted in 10–45% and 16–46% more anthocyanins than non-acidified solvents of ethanol and methanol, respectively. On average, glucose production ranged from 268 to 395 mg/g dry ISP. Solid residues that went through extraction with acidified ethanol at 50 °C at 17% (w/v) solid loading had the highest average production of glucose at 395 mg/g dry ISP. Residues from methanol solvents had lower glucose production after hydrolysis compared to those of ethanol based extraction. Fermentation of produced sugars from ISP residues was limited, where 38% less ethanol was produced from extraction residues compared to treatments that did not undergo initial extraction. Overall, purple-fleshed ISPs are amenable to anthocyanin and phenolic extraction, making it a suitable substrate for development of industrial colorants and dyes. However, more research is needed to obtain a suitable extraction point when trying to achieve a high recovery of anthocyanins and effective starch conversion to fermentable glucose.}, number={3}, journal={INDUSTRIAL CROPS AND PRODUCTS}, author={Bridgers, E. Nicole and Chinn, Mari S. and Truong, Van-Den}, year={2010}, month={Nov}, pages={613–620} }
 @article{kumar_sandeep_alavi_truong_gorga_2010, title={Preparation and characterization of bio-nanocomposite films based on soy protein isolate and montmorillonite using melt extrusion}, volume={100}, ISSN={["1873-5770"]}, DOI={10.1016/j.jfoodeng.2010.04.035}, abstractNote={The non-biodegradable and non-renewable nature of plastic packaging has led to a renewed interest in packaging materials based on bio-nanocomposites (biopolymer matrix reinforced with nanoparticles such as layered silicates). Bio-nanocomposite films based on soy protein isolate (SPI) and montmorillonite (MMT) were prepared using melt extrusion. Effects of the pH of film forming solution, MMT content, and extrusion processing parameters (screw speed and barrel temperature distribution) on the structure and properties of SPI–MMT bio-nanocomposite films were investigated. X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) were used for structural characterization of the films. Properties of the films were determined by tensile testing, dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), and water vapor barrier measurement. The arrangement of MMT in the soy protein matrix ranged from exfoliated at lower MMT content (5%) to intercalated at higher MMT content (15%). There was a significant improvement in mechanical (tensile strength and percent elongation at break) and dynamic mechanical properties (glass transition temperature and storage modulus), thermal stability, and water vapor permeability of the films with the addition of MMT. The results presented in this study show the feasibility of using bio-nanocomposite technology to improve the properties of biopolymer films based on SPI.}, number={3}, journal={JOURNAL OF FOOD ENGINEERING}, author={Kumar, P. and Sandeep, K. P. and Alavi, S. and Truong, V. D. and Gorga, R. E.}, year={2010}, month={Oct}, pages={480–489} }
 @article{truong_deighton_thompson_mcfeeters_dean_pecota_yencho_2009, title={Characterization of Anthocyanins and Anthocyanidins in Purple-Fleshed Sweetpotatoes by HPLC-DAD/ESI-MS/MS}, volume={58}, ISSN={0021-8561 1520-5118}, url={http://dx.doi.org/10.1021/jf902799a}, DOI={10.1021/jf902799a}, abstractNote={Purple-fleshed sweetpotatoes (PFSP) can be a healthy food choice for consumers and a potential source for natural food colorants. This study aimed to identify anthocyanins and anthocyanidins in PFSP, and to evaluate the effect of thermal processing on these polyphenolic compounds. Freeze-dried powder of raw and steamed samples of three PFSP varieties were extracted with acidified methanol using a Dionex ASE 200 accelerated solvent extractor. Seventeen anthocyanins were identified by HPLC-DAD/ESI-MS/MS for Stokes Purple and NC 415 varieties with five major compounds: cyanidin 3-caffeoylsophoroside-5-glucoside, peonidin 3-caffeoylsophoroside-5-glucoside, cyanidin 3-caffeoyl-p-hydroxybenzoylsophoroside-5-glucoside, peonidin 3-caffeoyl-p-hydroxybenzoyl-sophoroside-5-glucoside, and peonidin-caffeoyl-feruloylsophoroside-5-glucoside. Okinawa variety showed 12 pigments with 3 major peaks identified as cyanidin 3-caffeoylsophoroside-5-glucoside, cyanidin 3-(6'',6'''-dicaffeoylsophoroside)-5-glucoside and cyanidin 3-(6''-caffeoyl-6'''-feruloylsophoroside)-5-glucoside. Steam cooking had no significant effect on total anthocyanin content or the anthocyanin pigments. Cyanidin and peonidin, which were the major anthocyanidins in the acid hydrolyzed extracts, were well separated and quantified by HPLC with external standards. Cyanidin and peonidin, which contribute to the blue and red hues of PFSP, can be simply quantified by HPLC after acid hydrolysis of the anthocyanins.}, number={1}, journal={Journal of Agricultural and Food Chemistry}, publisher={American Chemical Society (ACS)}, author={Truong, Van-Den and Deighton, Nigel and Thompson, Roger T. and McFeeters, Roger F. and Dean, Lisa O. and Pecota, Kenneth V. and Yencho, G. Craig}, year={2009}, month={Dec}, pages={404–410} }
 @article{yencho_pecota_schultheis_vanesbroeck_holmes_little_thornton_truong_2008, title={'Covington' sweetpotato}, volume={43}, ISSN={["0018-5345"]}, DOI={10.21273/hortsci.43.6.1911}, abstractNote={‘Covington’ is an orange-fleshed, smooth-skinned, rose-colored, table-stock sweetpotato [Ipomoea batatas (L.) Lam.] developed by North Carolina State University (NCSU). ‘Covington’, named after the late Henry M. Covington, an esteemed sweetpotato scientist at North Carolina State, was evaluated as NC98-608 in multiple state and regional yield trials during 2001 to 2006. ‘Covington’ produces yields equal to ‘Beauregard’, a dominant sweetpotato variety produced in the United States, but it is typically 5 to 10 days later in maturity. ‘Covington’ typically sizes its storage roots more evenly than ‘Beauregard’ resulting in fewer jumbo class roots and a higher percentage of number one roots. Total yields are similar for the two clones with the dry matter content of ‘Covington’ storage roots typically being 1 to 2 points higher than that of ‘Beauregard’. ‘Covington’ is resistant to fusarium wilt [Fusarium oxysporum Schlect. f.sp. batatas (Wollenw.) Snyd. & Hans.], southern root-knot nematode [Meloidogyne incognita (Kofoid & White 1919) Chitwood 1949 race 3], and moderately resistant to streptomyces soil rot [Streptomyces ipomoeae (Person & W.J. Martin) Wakswan & Henrici]. Symptoms of the russet crack strain of Sweet Potato Feathery Mottle Virus have not been observed in ‘Covington’. The flavor of the baked storage roots of ‘Covington’ has been rated as very good by standardized and informal taste panels and typically scores as well or better in this regard when compared with ‘Beauregard’.}, number={6}, journal={HORTSCIENCE}, author={Yencho, G. Craig and Pecota, Kenneth V. and Schultheis, Jonathan R. and VanEsbroeck, Zvezdana-Pesic and Holmes, Gerald J. and Little, Billy E. and Thornton, Allan C. and Truong, Van-Den}, year={2008}, month={Oct}, pages={1911–1914} }
 @article{steed_truong_2008, title={Anthocyanin content, antioxidant activity, and selected physical properties of flowable purple-fleshed sweetpotato purees}, volume={73}, ISSN={["1750-3841"]}, DOI={10.1111/j.1750-3841.2008.00774.x}, abstractNote={ABSTRACT:  With high levels of polyphenolic compounds, purple‐fleshed sweetpotatoes (PFSP) have been utilized as a healthy food commodity and source of natural food colorants in Asia. In the U.S. sweetpotato industry, there are growing interests in exploring these market opportunities for PFSP. A locally grown PFSP cultivar was analyzed for antioxidant properties. The total phenolic content ranged from 313.6 to 1483.7 mg chlorogenic acid equivalent/100 g fresh weight (fw), and anthocyanin contents were between 51.5 and 174.7 mg anthocyanins/100 g fw. The DPPH radical scavenging activities and were 47.0 to 87.4 μmol trolox equivalent (TE)/g fw, and the oxygen radical absorbance capacity (ORAC) values were between 26.4 and 78.2 μmol TE/g fw. Unlike orange‐fleshed sweetpotatoes (OFSP), the steamed roots of PFSP formed a thick paste, which required a process modification to produce flowable purees. Rheological testing indicated that adjusting the dry matter of PFSP to 18%‐21% produced purees with flow properties similar to the OFSP purees. The PFSP purees had polyphenolic content and antioxidant capacity within ranges reported for various purple‐colored fruits and vegetables.}, number={5}, journal={JOURNAL OF FOOD SCIENCE}, author={Steed, L. E. and Truong, V. -D.}, year={2008}, pages={S215–S221} }
 @article{steed_truong_simunovic_sandeep_kumar_cartwright_swartzel_2008, title={Continuous Flow Microwave-Assisted Processing and Aseptic Packaging of Purple-Fleshed Sweetpotato Purees}, volume={73}, ISSN={["1750-3841"]}, DOI={10.1111/j.1750-3841.2008.00950.x}, abstractNote={ABSTRACT:  Pumpable purees from purple‐flesh sweetpotatoes (PFSP) were subjected to microwave heating using a 60 kW, 915 MHz continuous flow system, followed by aseptic packaging in flexible containers to obtain a shelf‐stable product. Initial test runs were conducted using a 5 kW 915 MHz microwave system to measure dielectric in‐line properties and examine the puree temperature profiles. The results demonstrated uniformity in heating of the puree at sterilization temperatures (>121 °C), and the dielectric constants and loss factors were within the range of published values for orange‐fleshed sweetpotato purees. The pilot‐scale test runs in a 60 kW microwave unit produced shelf‐stable puree packages stable at room temperature. Polyphenolic content of the PFSP purees were evaluated and the results showed that while total phenolics increased (5.9%) and total monomeric anthocyanins slightly decreased (14.5%) with microwave application, antioxidant activity determined by 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging activity and oxygen radical absorbance capacity (ORAC) assays did not significantly change as a result of microwave processing. Color values showed that microwave‐processed samples differed from fresh puree in saturation and hue angle, but not in overall color change. PFSP purees increased in gel strength when microwave processed, packaged, and stored, but the gel could be easily disrupted into flowable purees. Overall, high‐quality retention can be obtained by microwave processing and aseptic packaging of PFSP purees so that they can be used as functional food ingredients.}, number={9}, journal={JOURNAL OF FOOD SCIENCE}, author={Steed, L. E. and Truong, V. -D. and Simunovic, J. and Sandeep, K. P. and Kumar, P. and Cartwright, G. D. and Swartzel, K. R.}, year={2008}, pages={E455–E462} }
 @article{brinley_truong_coronel_simunovic_sandeep_2008, title={Dielectric properties of sweet potato purees at 915 MHZ as affected by temperature and chemical composition}, volume={11}, ISSN={["1532-2386"]}, DOI={10.1080/10942910701284291}, abstractNote={A process for rapid sterilization and aseptic packaging of sweet potato puree using a continuous flow microwave system operating at 915 MHz has been successfully developed. In microwave processing, dielectric properties have a major role in determining the interaction between purees and the electromagnetic energy. The objective of this research was to determine how dielectric properties are affected by temperature and chemical composition of purees derived from thirteen sweet potato cultivars with varying flesh colors. Results indicated that temperature, moisture, sugar and starch content had a pronounced effect (p < 0.001) on dielectric properties measured from 15°C to 145°C at 915 MHz. Dielectric constant decreased with increasing temperature, while dielectric loss factor increased quadratically. Power penetration depth of all cultivars decreased with increasing temperature. Predictive equations were developed for dielectric constant (R2 = 0.82) and dielectric loss factor (R2 = 0.90) as a function of temperature, moisture, sugar, and starch. The predictive equations would be useful in determining the dielectric properties of sweet potato purees for the microwave processing technology.}, number={1}, journal={INTERNATIONAL JOURNAL OF FOOD PROPERTIES}, author={Brinley, T. A. and Truong, V. D. and Coronel, P. and Simunovic, J. and Sandeep, K. P.}, year={2008}, pages={158–172} }
 @article{perez-diaz_truong_webber_mcfeeters_2008, title={Microbial growth and the effects of mild acidification and preservatives in refrigerated sweet potato puree}, volume={71}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-71.3.639}, abstractNote={Refrigerated sweet potato puree is a convenient form of sweet potato that can be used as an ingredient in formulated foods. The microbiology of refrigerated sweet potato puree during storage for up to 5 weeks was evaluated. Because the puree was made by comminuting steam-cooked sweet potatoes before refrigeration, no naturally occurring vegetative bacterial cells were detected during a 4-week period of refrigerated storage at 4 degrees C. However, if postprocessing microbial contamination of the puree were to occur, contaminating microorganisms such as Listeria monocytogenes could grow during refrigerated storage. The effects of acidification or the addition of potassium sorbate and sodium benzoate on a population of L. monocytogenes inoculated into refrigerated (4 degrees C) sweet potato puree were determined. Inoculation of the refrigerated puree with L. monocytogenes at 10(6) CFU/ml resulted in a 3-log increase after 3 weeks storage of nonsupplemented puree. Supplementation of the sweet potato puree with 0.06% (wt/vol) sorbic acid or benzoic acid plus mild acidification of the sweet potato puree with citric acid to pH 4.2 prevented growth of L. monocytogenes during storage at 4 degrees C.}, number={3}, journal={JOURNAL OF FOOD PROTECTION}, author={Perez-Diaz, Ilenys M. and Truong, Van-Den and Webber, Ashlee and Mcfeeters, Roger F.}, year={2008}, month={Mar}, pages={639–642} }
 @article{grabowski_truong_daubert_2008, title={Nutritional and rheological characterization of spray dried sweetpotato powder}, volume={41}, ISSN={["0023-6438"]}, DOI={10.1016/j.lwt.2007.02.019}, abstractNote={Spray drying feasibility of sweetpotato puree is enhanced using alpha-amylase treatment to reduce puree viscosity and maltodextrin (MD) addition to facilitate drying. To better determine potential applications of powders produced with various levels of amylase and MD, nutrient composition and rheological properties of the hydrated spray dried sweetpotato powders were examined and compared with sweetpotato puree. Proximate composition, beta-carotene, vitamin C, and mineral analyses were performed. Steady shear rheology of reconstituted powder solutions was also evaluated at different temperatures and shear rates. Spray drying significantly reduced the β-carotene and ascorbic acid contents. Additionally, the all-trans form of beta-carotene was further transformed to the cis-isomers during dehydration. The viscosity of the reconstituted solutions was much lower than that of the puree at the same solid concentration. Rheologically, the reconstituted sweetpotato slurries behaved similarly to pregelatinized starch solutions. Thus, spray dried sweetpotato powders have a potential to enhance food systems as a thickener despite the need for increased nutrient retention.}, number={2}, journal={LWT-FOOD SCIENCE AND TECHNOLOGY}, author={Grabowski, J. A. and Truong, V. -D. and Daubert, C. R.}, year={2008}, pages={206–216} }
 @article{kumar_coronel_truong_simunovic_swartzel_sandeep_cartwright_2008, title={Overcoming issues associated with the scale-up of a continuous flow microwave system for aseptic processing of vegetable purees}, volume={41}, ISSN={["1873-7145"]}, DOI={10.1016/j.foodres.2007.11.004}, abstractNote={Continuous flow microwave heating is a promising alternative to conventional heating for aseptic processing of low-acid vegetable purees. However, non-uniform temperature distribution and control of processing parameters are the major hurdles in the implementation of continuous flow microwave heating. This study was undertaken to overcome issues associated with the scale-up of a continuous flow microwave system from pilot plant scale to industrial scale and to conduct extended run times of 8 h based on the procedure developed. Dielectric properties and cross-sectional temperature profiles were measured during processing of green pea puree and carrot puree from 20 to 130 °C in a 5-kW continuous flow microwave system. During processing of green peas, cross-sectional temperature differences of 8.6 and 5 °C were observed at the outlet for center temperatures of 50 and 130 °C respectively. These temperature differences were 32.9 and 3.6 °C for carrot puree. For process scale-up, green pea puree and carrot puree were processed in a 60-kW microwave system with the objective of successful operation for at least 8 h. Static mixers, installed at the exit of each of the microwave applicators, improved temperature uniformity for both purees. Successful completion of processing the purees for 8 h in the 60-kW microwave system showed the potential for the scale-up of a continuous flow microwave system from pilot plant scale to industrial scale.}, number={5}, journal={FOOD RESEARCH INTERNATIONAL}, author={Kumar, P. and Coronel, P. and Truong, V. D. and Simunovic, J. and Swartzel, K. R. and Sandeep, K. P. and Cartwright, G.}, year={2008}, pages={454–461} }
 @article{teow_truong_mcfeeters_thompson_pecota_yencho_2007, title={Antioxidant activities, phenolic and beta-carotene contents of sweet potato genotypes with varying flesh colours}, volume={103}, ISSN={["1873-7072"]}, DOI={10.1016/j.foodchem.2006.09.033}, abstractNote={Antioxidant activities (μmol Trolox equivalent (TE)/g fresh weight) of 19 sweet potato genotypes with distinctive flesh colour (white, cream, yellow, orange and purple) were measured by oxygen radical absorbance capacity (ORAC), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and 2,2′-azinobis(3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS). Total phenolics were measured using the Folin–Ciocalteau method, total anthocyanins by the pH-differential method, and β-carotene by HPLC. The total antioxidant activity (hydrophilic + lipophilic ORAC) was highest (27.2 μmol TE/g fresh weight (fw)) for NC415 (purple-fleshed) and lowest (2.72 μmol TE/g fw) for Xushu 18 (white-fleshed). The hydrophilic-ORAC values were significantly correlated with the DPPH (R2 = 0.859) and ABTS (R2 = 0.761) values. However, the lipophilic-ORAC values were poorly correlated with the β-carotene contents (R2 = 0.480). The total phenolic contents (0.011–0.949 mg chlorogenic acid equivalent/g fw) were highly correlated with the hydrophilic-ORAC (R2 = 0.937) and DPPH (R2 = 0.820) values. Therefore, the total phenolic content can serve as a useful indicator for the antioxidant activities of sweet potatoes.}, number={3}, journal={FOOD CHEMISTRY}, publisher={Elsevier BV}, author={Teow, Choong C. and Truong, Van-Den and McFeeters, Roger F. and Thompson, Roger L. and Pecota, Kenneth V. and Yencho, G. Craig}, year={2007}, pages={829–838} }
 @article{brinley_stam_truong_coronel_kumar_simunovic_sandeep_cartwright_swartzel_jaykus_et al._2007, title={Feasibility of utilizing bioindicators for testing microbial inactivation in sweetpotato purees processed with a continuous-flow microwave system}, volume={72}, ISSN={["0022-1147"]}, DOI={10.1111/j.1750-3841.2007.00371.x}, abstractNote={ABSTRACT:  Continuous‐flow microwave heating has potential in aseptic processing of various food products, including purees from sweetpotatoes and other vegetables. Establishing the feasibility of a new processing technology for achieving commercial sterility requires evaluating microbial inactivation. This study aimed to assess the feasibility of using commercially available plastic pouches of bioindicators containing spores of Geobacillius stearothermophilus ATCC 7953 and Bacillus subtilis ATCC 35021 for evaluating the degree of microbial inactivation achieved in vegetable purees processed in a continuous‐flow microwave heating unit. Sweetpotato puree seeded with the bioindicators was subjected to 3 levels of processing based on the fastest particles: undertarget process (F0 approximately 0.65), target process (F0 approximately 2.8), and overtarget process (F0 approximately 10.10). After initial experiments, we found it was necessary to engineer a setup with 2 removable tubes connected to the continuous‐flow microwave system to facilitate the injection of indicators into the unit without interrupting the puree flow. Using this approach, 60% of the indicators injected into the system could be recovered postprocess. Spore survival after processing, as evaluated by use of growth indicator dyes and standard plating methods, verified inactivation of the spores in sweetpotato puree. The log reduction results for B. subtilis were equivalent to the predesigned degrees of sterilization (F0). This study presents the first report suggesting that bioindicators such as the flexible, food‐grade plastic pouches can be used for microbial validation of commercial sterilization in aseptic processing of foods using a continuous‐flow microwave system.}, number={5}, journal={JOURNAL OF FOOD SCIENCE}, author={Brinley, T. A. and Stam, C. N. and Truong, V. D. and Coronel, P. and Kumar, P. and Simunovic, J. and Sandeep, K. P. and Cartwright, G. D. and Swartzel, K. R. and Jaykus, L. A. and et al.}, year={2007}, pages={E235–E242} }
 @article{kumar_coronel_simunovic_truong_sandeep_2007, title={Measurement of dielectric properties of pumpable food materials under static and continuous flow conditions}, volume={72}, ISSN={["0022-1147"]}, DOI={10.1111/j.1750-3841.2007.00315.x}, abstractNote={ABSTRACT:  Continuous flow microwave sterilization is an emerging technology that has the potential to replace the conventional heating processes for viscous and pumpable food products. Dielectric properties of pumpable food products were measured by a new approach (under continuous flow conditions) at a temperature range of 20 to 130 °C and compared with those measured by the conventional approach (under static conditions). The food products chosen for this study were skim milk, green pea puree, carrot puree, and salsa con queso. Second‐order polynomial correlations for the dependence of dielectric properties at 915 MHz of the food products on temperature were developed. Dielectric properties measured under static and continuous flow conditions were similar for homogeneous food products such as skim milk and vegetable puree, but they were significantly different for salsa con queso, which is a multiphase food product. The results from this study suggest that, for a multiphase product, dielectric properties measured under continuous flow conditions should be used for designing a continuous flow microwave heating system.}, number={4}, journal={JOURNAL OF FOOD SCIENCE}, author={Kumar, P. and Coronel, P. and Simunovic, J. and Truong, V. D. and Sandeep, K. P.}, year={2007}, month={May}, pages={E177–E183} }
 @article{truong_mcfeeters_thompson_dean_shofran_2007, title={Phenolic acid content and composition in leaves and roots of common commercial sweetpotato (Ipomea batatas L.) cultivars in the United States}, volume={72}, ISSN={["1750-3841"]}, DOI={10.1111/j.1750-3841.2007.00415.x}, abstractNote={ABSTRACT:  Phenolic acids in commercially important sweet potato cultivars grown in the United States were analyzed using reversed‐phase high‐performance liquid chromatography (HPLC). Caffeic acid, chlorogenic acid, 4,5‐di‐O‐caffeoylquinic acid, 3,5‐di‐O‐caffeoylquinic acid, and 3,4‐di‐O‐caffeoylquinic acid were well separated with an isocratic elution in less than 25 min compared to about 120 min for analyzing and re‐equilibrating the column with a gradient method. The isocratic elution order of these caffeoylquinic acid derivatives was confirmed by LC‐MS/MS. Chlorogenic acid was the highest in root tissues, while 3,5‐di‐O‐caffeoylquinic acid and/or 4,5‐di‐O‐caffeoylquinic acid were predominant in the leaves. Steam cooking resulted in statistically nonsignificant increases in the concentration of total phenolics and all the individual phenolic acids identified. Sweetpotato leaves had the highest phenolic acid content followed by the peel, whole root, and flesh tissues. However, there was no significant difference in the total phenolic content and antioxidant activity between purees made from the whole and peeled sweet potatoes.}, number={6}, journal={JOURNAL OF FOOD SCIENCE}, author={Truong, V.-D. and McFeeters, R. F. and Thompson, R. T. and Dean, L. L. and Shofran, B.}, year={2007}, month={Aug}, pages={C343–C349} }
 @article{shih_truong_daigle_2006, title={Physicochemical properties of gluten-free pancakes from rice and sweet potato flours}, volume={29}, ISSN={["0146-9428"]}, DOI={10.1111/j.1745-4557.2005.00059.x}, abstractNote={ABSTRACT}, number={1}, journal={JOURNAL OF FOOD QUALITY}, author={Shih, FF and Truong, VD and Daigle, KW}, year={2006}, month={Feb}, pages={97–107} }
 @article{grabowski_truong_daubert_2006, title={Spray-drying of amylase hydrolyzed sweetpotato puree and physicochemical properties of powder}, volume={71}, ISSN={["1750-3841"]}, DOI={10.1111/j.1750-3841.2006.00036.x}, abstractNote={ABSTRACT:  Spray‐drying, which has been used for commercial production of functional ingredients from several fruits and vegetables, has not yet been studied for sweetpotato processing. Thus, the objective was to determine the effects of viscosity reduction of sweetpotato puree with alpha‐amylase, maltodextrin (MD) addition, and inlet air temperature on the physicochemical characteristics of spray‐dried sweetpotato powder. A face‐centered cube design was used to evaluate the effects of amylase level (0, 3.75, and 7.5 mL/kg puree), MD concentration (0%, 10%, and 20%), and inlet air temperature (150 °C, 190 °C, and 220 °C) on powder characteristics. Model‐fitting using response surface methodology was performed to examine the effects of independent variables on the moisture content, color, water absorption, solubility, particle size, bulk density, and glass transition temperature. The data were fit to a full second order polynomial equation. However, only the linear and quadratic terms proved to be significant for most dried powder attributes. MD significantly increased powder solubility, altered the hue value, and raised the glass transition temperature of the powder. Pretreatment with alpha‐amylase resulted in a lower glass transition temperature and a decrease in particle size. Overall, results show that good quality sweetpotato powders can be produced using this drying method, with potential applications in food and nutraceutical products.}, number={5}, journal={JOURNAL OF FOOD SCIENCE}, author={Grabowski, J. A. and Truong, V. -D. and Daubert, C. R.}, year={2006}, pages={E209–E217} }
 @article{coronel_truong_sandeep_cartwright_2005, title={Aseptic processing of sweetpotato purees using a continuous flow microwave system}, volume={70}, DOI={10.1111/j.1365-2621.2005.tb08315.x}, abstractNote={obtain a shelf-stable product. The dielectric properties of SPP were measured, and the dielectric constant and loss obtain a shelf-stable product. The dielectric properties of SPP were measured, and the dielectric constant and loss obtain a shelf-stable product. The dielectric properties of SPP were measured, and the dielectric constant and loss obtain a shelf-stable product. The dielectric properties of SPP were measured, and the dielectric constant and loss factor were within the range of the published values for fruits and vegetables. Small-scale tests were conducted in a factor were within the range of the published values for fruits and vegetables. Small-scale tests were conducted in a factor were within the range of the published values for fruits and vegetables. Small-scale tests were conducted in a factor were within the range of the published values for fruits and vegetables. Small-scale tests were conducted in a factor were within the range of the published values for fruits and vegetables. Small-scale tests were conducted in a 5-kW microwave unit to determine changes in color and viscosity with different thermal treatments. The results of 5-kW microwave unit to determine changes in color and viscosity with different thermal treatments. The results of 5-kW microwave unit to determine changes in color and viscosity with different thermal treatments. The results of 5-kW microwave unit to determine changes in color and viscosity with different thermal treatments. The results of 5-kW microwave unit to determine changes in color and viscosity with different thermal treatments. The results of these tests showed that color values ( these tests showed that color values ( these tests showed that color values ( these tests showed that color values ( these tests showed that color values (L*, *, *, *, a a a a a*) and viscosity did not change significantly compared with the untreated *) and viscosity did not change significantly compared with the untreated *) and viscosity did not change significantly compared with the untreated *) and viscosity did not change significantly compared with the untreated *) and viscosity did not change significantly compared with the untreated control. Pilot-scale tests were then conducted in a 60-kW microwave unit where the product was heated to 135 °C control. Pilot-scale tests were then conducted in a 60-kW microwave unit where the product was heated to 135 °C control. Pilot-scale tests were then conducted in a 60-kW microwave unit where the product was heated to 135 °C control. Pilot-scale tests were then conducted in a 60-kW microwave unit where the product was heated to 135 °C control. Pilot-scale tests were then conducted in a 60-kW microwave unit where the product was heated to 135 °C and held at that temperature for 30 s. The pilot-scale test produced a shelf-stable product with no detectable and held at that temperature for 30 s. The pilot-scale test produced a shelf-stable product with no detectable and held at that temperature for 30 s. The pilot-scale test produced a shelf-stable product with no detectable and held at that temperature for 30 s. The pilot-scale test produced a shelf-stable product with no detectable and held at that temperature for 30 s. The pilot-scale test produced a shelf-stable product with no detectable microbial count during a 90-d storage period at room temperature. This is the 1st report of aseptically packaged microbial count during a 90-d storage period at room temperature. This is the 1st report of aseptically packaged microbial count during a 90-d storage period at room temperature. This is the 1st report of aseptically packaged microbial count during a 90-d storage period at room temperature. This is the 1st report of aseptically packaged microbial count during a 90-d storage period at room temperature. This is the 1st report of aseptically packaged vegetable puree processed by a continuous flow microwave heating system. vegetable puree processed by a continuous flow microwave heating system. vegetable puree processed by a continuous flow microwave heating system. vegetable puree processed by a continuous flow microwave heating system. vegetable puree processed by a continuous flow microwave heating system.}, number={9}, journal={Journal of Food Science}, author={Coronel, P. and Truong, Simunovic J. Van-Den and Sandeep, KP and Cartwright, G. D.}, year={2005}, pages={E531–536} }
 @misc{williams_wright_den truong_daubert_vinyard_2005, title={Mechanical properties of foods used in experimental studies of primate masticatory function}, volume={67}, ISSN={["1098-2345"]}, DOI={10.1002/ajp.20189}, abstractNote={In vivo studies of jaw-muscle behavior have been integral factors in the development of our current understanding of the primate masticatory apparatus. However, even though it has been shown that food textures and mechanical properties influence jaw-muscle activity during mastication, very little effort has been made to quantify the relationship between the elicited masticatory responses of the subject and the mechanical properties of the foods that are eaten. Recent work on human mastication highlights the importance of two mechanical properties-toughness and elastic modulus (i.e., stiffness)-for food breakdown during mastication. Here we provide data on the toughness and elastic modulus of the majority of foods used in experimental studies of the nonhuman primate masticatory apparatus. Food toughness ranges from approximately 56.97 Jm(-2) (apple pulp) to 4355.45 Jm(-2) (prune pit). The elastic modulus of the experimental foods ranges from 0.07 MPa for gummy bears to 346 MPa for popcorn kernels. These data can help researchers studying primate mastication select among several potential foods with broadly similar mechanical properties. Moreover, they provide a framework for understanding how jaw-muscle activity varies with food mechanical properties in these studies.}, number={3}, journal={AMERICAN JOURNAL OF PRIMATOLOGY}, author={Williams, SH and Wright, BW and Den Truong, V and Daubert, CR and Vinyard, CJ}, year={2005}, month={Nov}, pages={329–346} }
 @article{mcconnell_truong_walter_mcfeeters_2005, title={Physical, chemical and microbial changes in shredded sweet potatoes}, volume={29}, ISSN={["1745-4549"]}, DOI={10.1111/j.1745-4549.2005.00026.x}, abstractNote={With the increasing demand for freshly cut vegetables, a substantial potential exists in developing minimally processed sweet potato products. This study was undertaken to determine the effects of semipermeable polymeric materials and modified atmosphere packaging (MAP) on quality changes and microbial growth in shredded sweet potatoes under refrigerated storage. Shredded sweet potatoes from two major commercial cultivars (Beauregard and Hernandez) were packed in low and medium O2permeability bags and flushed with gas composed of 5% O2, 4% CO2and 91% N2. Quality changes and microbial growth were monitored in comparison to the samples packed in air using high-O2permeable films. The quality of shredded sweet potatoes could be maintained for 7 days at 4C in air, but extended up to 14 days in MAP. Considering the parameters measured in this investigation, the best results were obtained by MAP using moderately O2-permeable film (7000 cm3/atm/m2/24 h). Shredded sweet potatoes stored in MAP showed less changes in tissue firmness, dry matter, ascorbic acid and starch than shredded sweet potatoes stored in air. The MAP-stored shredded sweet potatoes consistently exhibited fewer total aerobic bacteria and enteric bacteria compared to the shredded sweet potatoes stored in air. Yeasts, molds, lactic acid bacteria, color, beta-carotene and sugars of all stored shredded sweet potatoes did not significantly change, regardless of treatments. Higher ethanol levels were generated in the MAP-stored shredded sweet potatoes after 10 days, but off-odors were not detected in any of the MAP-stored shredded sweet potatoes.}, number={3-4}, journal={JOURNAL OF FOOD PROCESSING AND PRESERVATION}, author={McConnell, R and Truong, VD and Walter, WM and McFeeters, RF}, year={2005}, pages={246–267} }
 @article{truong_clare_catignani_swaisgood_2004, title={Cross-linking and rheological changes of whey proteins treated with microbial transglutaminase}, volume={52}, ISSN={["1520-5118"]}, DOI={10.1021/jf034397c}, abstractNote={Modification of the functionality of whey proteins using microbial transglutaminase (TGase) has been the subject of recent studies. However, changes in rheological properties of whey proteins as affected by extensive cross-linking with TGase are not well studied. The factors affecting cross-linking of whey protein isolate (WPI) using both soluble and immobilized TGase were examined, and the rheological properties of the modified proteins were characterized. The enzyme was immobilized on aminopropyl glass beads (CPG-3000) by selective adsorption of the biotinylated enzyme on avidin that had been previously immobilized. WPI (4 and 8% w/w) in deionized water, pH 7.5, containing 10 mM dithiothreitol was cross-linked using enzyme/substrate ratios of 0.12-10 units of activity/g WPI. The reaction was carried out in a jacketed bioreactor for 8 h at 40 degrees C with continuous circulation. The gel point temperature of WPI solutions treated with 0.12 unit of immobilized TGase/g was slightly decreased, but the gel strength was unaffected. However, increasing the enzyme/substrate ratio resulted in extensive cross-linking of WPI that was manifested by increases in apparent viscosity and changes in the gelation properties. For example, using 10 units of soluble TGase/g resulted in extensive cross-linking of alpha-lactalbumin and beta-lactoglobulin in WPI, as evidenced by SDS-PAGE and Western blotting results. Interestingly, the gelling point of WPI solutions increased from 68 to 94 degrees C after a 4-h reaction, and the gel strength was drastically decreased (lower storage modulus, G'). Thus, extensive intra- and interchain cross-linking probably caused formation of polymers that were too large for effective network development. These results suggest that a process could be developed to produce heat-stable whey proteins for various food applications.}, number={5}, journal={JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY}, author={Truong, VD and Clare, DA and Catignani, GL and Swaisgood, HE}, year={2004}, month={Mar}, pages={1170–1176} }
 @article{walter_truong_simunovic_mcfeeters_2003, title={Low-temperature blanching of sweetpotatoes to improve firmness firmness retention: Effect on compositional and textural properties}, volume={68}, ISSN={["0022-1147"]}, DOI={10.1111/j.1365-2621.2003.tb09633.x}, abstractNote={ABSTRACT:  Low‐temperature blanching of sweetpotatoes (SP) prior to cooking has been shown to significantly increase firmness retention. This research investigated the effect of blanching on firmness, pectin methylesterase activity (PME), pectin methylation, and galacturonic acid and cell wall material concentrations in SP tissue subjected to blanching and cooking treatments. PME activity decreased 82% after 20 min of blanching in water at 62°C, while sample firmness continued to increase with blanching time (3.5 N for unblanched and 19.0 N for 90 min blanched, and cooked tissue), indicating that firming due to pectin demethylation explains part of the observed increased firmness retention caused by low‐temperature blanching, but unknown factors also play a role.,}, number={4}, journal={JOURNAL OF FOOD SCIENCE}, author={Walter, WM and Truong, VD and Simunovic, N and McFeeters, RF}, year={2003}, month={May}, pages={1244–1247} }
 @article{truong_daubert_2003, title={Rheological methods for assessment of food freshness and stability}, volume={836}, DOI={10.1021/bk-2003-0836.ch019}, abstractNote={Food rheology is considered the material science for food systems. Rheological approaches to shelf-life and freshness may range from a simple squeezing technique to advanced oscillatory methodologies probing material microstructure. As rheology relates to consumer perceptions of quality and freshness, a more common sensory term, texture, is employed. Changes in texture and stability during storage have been recognized as important factors influencing consumer acceptability of many food products. Texture is a complex attribute of food quality and can only be measured directly by sensory evaluation. However, many instrumental methods are used to measure mechanical properties of foods that are, up to a certain extent, related to sensory characteristics. Large strain methods such as puncture, penetration, bending, tension, shear, compression, and texture profile analysis are commonly used to evaluate freshness and textural changes of foods with respect to storage conditions. For fluid foods, various rheological techniques evaluate yield stress and shear viscosity, providing information about pourability, thickness, and dispersion or emulsion stability over time. Small strain methods, specifically dynamic oscillatory shear and mechanical analyses, are useful in probing microstructure, viscoelastic properties, and phase transitions in food materials. This chapter reviews rheological methods applicable to assessment of freshness and textural stability of foods.}, journal={Freshness and shelf life of foods}, publisher={Washington, DC: American Chemical Society}, author={Truong, V. D. and Daubert, C. R.}, editor={K. R. Cadwallader, H. WeenenEditor}, year={2003}, pages={248–268} }
 @article{wang_truong_wang_2003, title={Structures and rheological properties of corn starch as affected by acid hydrolysis}, volume={52}, ISSN={["1879-1344"]}, DOI={10.1016/S0144-8617(02)00323-5}, abstractNote={Common corn starch was treated with different concentrations of hydrochloric acid, 0.06, 0.14, and 1.0N, for different lengths of time, 18, 6, and 1 h, respectively, to reach a similar peak viscosity as measured by Brabender Viscoamylograph. The fine structures, crystallinity and thermal properties were characterized and the rheological properties were evaluated using both compression and dynamic oscillatory tests. Acid hydrolysis had little effect on amylopectin branch chain-length distribution, gelatinization and retrogradation properties. However, the higher acid concentration (1.0N) degraded both amylopectin and amylose to a greater extent compared with the other two lower acid concentrations (0.06 and 0.14N). The acid treated starches had slightly higher degrees of crystallinity and lower amylose content than did the unmodified starch. Degradation of amylose and amylopectin by a high acid concentration resulted in a decrease in storage modulus (G′), loss modulus (G″), gelling temperature, and gel strength of the acid-thinned starches.}, number={3}, journal={CARBOHYDRATE POLYMERS}, author={Wang, YJ and Truong, VD and Wang, LF}, year={2003}, month={May}, pages={327–333} }
 @article{walter_truong_espinel_2002, title={Textural measurements and product quality of restructured sweetpotato french fries}, volume={35}, ISSN={["0023-6438"]}, DOI={10.1006/fstl.2001.0840}, abstractNote={The objectives of this research were to investigate the applicability of using an alginate–calcium gelling system to produce a French fry-type product using high beta-carotene sweetpotato puree as the main ingredient and to compare four instrumental methods of texture measurement for this product type in relation to sensory textural properties. Sweetpotato puree made with Jewel cultivar sweetpotatoes was restructured using optimized alginate–calcium concentrations. A consumer panel scored sweetpotato fries containing 0.35 g alginate/100 g and 0.5 g CaSO4/100 g highest for appearance, texture, flavor, and overall acceptability. A trained texture profile panel described the product with 15 texture notes. Of these attributes, nine sensory notes describing hardness, mastication shear, cohesiveness, springiness, moistness, and oiliness were highly correlated with some instrumental parameters (r=0.79–0.92) for measuring textural properties. The instrumental methods evaluated were instrumental texture profile analysis, three-point bending force, Kramer shear force, and puncture force. Among these instrumental methods, Kramer shear appeared to be the method of choice because of method's simplicity and high precision (coefficient of variation ≤10%).}, number={3}, journal={LEBENSMITTEL-WISSENSCHAFT UND-TECHNOLOGIE-FOOD SCIENCE AND TECHNOLOGY}, author={Walter, WM and Truong, VD and Espinel, KR}, year={2002}, pages={209–215} }
 @article{truong_daubert_drake_baxter_2002, title={Vane rheometry for textural characterization of cheddar cheeses: Correlation with other instrumental and sensory measurements}, volume={35}, ISSN={["0023-6438"]}, DOI={10.1006/fstl.2001.0872}, abstractNote={Abstract The relationship between instrumental (vane method, texture profile analysis (TPA), uniaxial compression) and sensory texture measurements of Cheddar cheeses was investigated. A Haake VT 550 viscotester equipped with a four-bladed vane rotor was used for the vane test. Instrumental TPA was performed with a TA.XT2 Texture Analyser, and compression variables were calculated from TPA data. Vane parameters were significantly correlated with respective variables of compression and TPA ( r =0.56–0.91), and sensory tests ( r =0.54–0.88). Multivariate analysis indicated that seven sensory attributes of ten commercial Cheddar cheeses were satisfactorily predicted (calibration regression coefficient, R cal >0.62) by variables of the vane, uniaxial compression and TPA tests. In particular, cheese firmness and cohesiveness evaluated by sensory panel were well described by vane stress and apparent strain. The results validate the vane method as an alternative to the existing cheese testing methods for rapid evaluation of cheese texture.}, number={4}, journal={LEBENSMITTEL-WISSENSCHAFT UND-TECHNOLOGIE-FOOD SCIENCE AND TECHNOLOGY}, author={Truong, VD and Daubert, CR and Drake, MA and Baxter, SR}, year={2002}, pages={305–314} }
 @misc{walter_truong_espinel_2001, title={Methods for producing cooked sweetpotato products and compositions thereof}, volume={6,197,363}, number={2001 Mar. 6}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Walter, W. M. and Truong, V. D. and Espinel, R. K.}, year={2001} }
 @article{truong_daubert_2001, title={Textural characterization of cheeses using vane rheometry and torsion analysis}, volume={66}, ISSN={["0022-1147"]}, DOI={10.1111/j.1365-2621.2001.tb04627.x}, abstractNote={ABSTRACT Vane rheometry was applied to textural characterization of cheeses and compared with torsion analysis. A Haake VT 550 viscotester was used for both vane and torsion tests at strain rates of 0.003 to 0.524 s‐1. Angular deformation and shear stress in the vane test increased with increasing low strain rate and was rate independent at higher rates. This shear rate dependency of stress and deformation varied with cheese types. Shear stresses from the vane method were lower than torsion shear stresses. Similar texture maps of cheeses were generated by plotting stress and strain or angular deformation values from the 2 testing methods. The findings indicate the vane technique can be used for rapid textural characterization of cheeses.}, number={5}, journal={JOURNAL OF FOOD SCIENCE}, author={Truong, VD and Daubert, CR}, year={2001}, pages={716–721} }
 @article{truong_daubert_2000, title={Comparative study of large strain methods for assessing failure characteristics of selected food gels}, volume={31}, ISSN={["0022-4901"]}, DOI={10.1111/j.1745-4603.2000.tb00294.x}, abstractNote={ABSTRACT}, number={3}, journal={JOURNAL OF TEXTURE STUDIES}, author={Truong, VD and Daubert, CR}, year={2000}, month={Sep}, pages={335–353} }
 @article{walter_truong_wiesenborn_carvajal_2000, title={Rheological and physicochemical properties of starches from moist- and dry-type sweetpotatoes}, volume={48}, DOI={10.1021/jf9909631}, number={7}, journal={Journal of Agricultural and Food Chemistry}, author={Walter, W. M. and Truong, V. D. and Wiesenborn, D. P. and Carvajal, P.}, year={2000}, pages={2937–2942} }
 @article{drake_gerard_truong_daubert_1999, title={Relationship between instrumental and sensory measurements of cheese texture}, volume={30}, ISSN={["0022-4901"]}, DOI={10.1111/j.1745-4603.1999.tb00230.x}, abstractNote={ABSTRACT}, number={4}, journal={JOURNAL OF TEXTURE STUDIES}, author={Drake, MA and Gerard, PD and Truong, VD and Daubert, CR}, year={1999}, month={Oct}, pages={451–476} }
 @article{drake_truong_daubert_1999, title={Rheological and sensory properties of reduced-fat processed cheeses containing lecithin}, volume={64}, ISSN={["0022-1147"]}, DOI={10.1111/j.1365-2621.1999.tb15123.x}, abstractNote={ABSTRACT}, number={4}, journal={JOURNAL OF FOOD SCIENCE}, author={Drake, MA and Truong, VD and Daubert, CR}, year={1999}, pages={744–747} }
 @article{walter_sylvia_truong_1998, title={Alkali-neutralization process maintains the firmness and sensory quality of canned sweetpotato pieces}, volume={21}, ISSN={["0146-9428"]}, DOI={10.1111/j.1745-4557.1998.tb00533.x}, abstractNote={ABSTRACT}, number={5}, journal={JOURNAL OF FOOD QUALITY}, author={Walter, WM and Sylvia, KE and Truong, VD}, year={1998}, month={Sep}, pages={421–431} }
 @article{daubert_tkachuk_truong_1998, title={Quantitative measurement of food spreadability using the vane method}, volume={29}, ISSN={["0022-4901"]}, DOI={10.1111/j.1745-4603.1998.tb00814.x}, abstractNote={ABSTRACT}, number={4}, journal={JOURNAL OF TEXTURE STUDIES}, author={Daubert, CR and Tkachuk, JA and Truong, VD}, year={1998}, month={Oct}, pages={427–435} }
 @article{truong_walter_bett_1998, title={Textural properties and sensory quality of processed sweet potatoes as affected by low temperature blanching}, volume={63}, DOI={10.1111/j.1365-2621.1998.tb15826.x}, abstractNote={ABSTRACT}, number={4}, journal={Journal of Food Science}, author={Truong, V. D. and Walter, W. M. and Bett, K. L.}, year={1998}, pages={739–743} }
 @article{walter_collins_truong_fine_1997, title={Physical, compositional, and sensory properties of French fry-type products from five sweetpotato selections}, volume={45}, ISSN={["0021-8561"]}, DOI={10.1021/jf960061+}, abstractNote={Strips from five sweetpotato (SP) cultivars (cv.) representing two different texture/flavor types were prepared and frozen. They were fried and their flavor and texture evaluated by sensory panels. Selected physical and compositional analyses were performed on raw and fried SP. An untrained preference panel tended to score the flavor of the sweeter types highest and the texture of the firm types higher than sweet types. A trained profile panel identified and scored flavor notes and texture categories. This research indicated that the intensity of the flavor notes sweetness and starch and the intensity of texture notes first-bite moistness and first-bite hardness were highly correlated with some of the compositional parameters. Correlation between compositional parameters and the flavor and texture note intensities listed above could be developed into a system to predict those sensory properties in newly developed selections without having to resort to sensory analyses. Keywords: Texture profile analysis; ...}, number={2}, journal={JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY}, author={Walter, WM and Collins, WW and Truong, VD and Fine, TI}, year={1997}, month={Feb}, pages={383–388} }
 @article{truong_walter_hamann_1997, title={Relationship between instrumental and sensory parameters of cooked sweetpotato texture}, volume={28}, ISSN={["0022-4901"]}, DOI={10.1111/j.1745-4603.1997.tb00109.x}, abstractNote={ABSTRACT}, number={2}, journal={JOURNAL OF TEXTURE STUDIES}, author={Truong, VD and Walter, WM and Hamann, DD}, year={1997}, month={Jun}, pages={163–185} }