@article{keefer_rovai_drake_2023, title={A Timely Application-Temporal methods, past, present, and future}, ISSN={["1750-3841"]}, DOI={10.1111/1750-3841.16491}, abstractNote={Eating is a dynamic experience, and temporal sensory methods have been proposed to document how products change over the course of consumption or use (nonfood). A search of online databases yielded approximately 170 sources related to temporal evaluation of food products that were compiled and reviewed. This review summarizes the evolution of temporal methodologies (past), offers guidance in selecting appropriate methods (present), and provides insights into the future of temporal methodologies in the sensory space. Temporal methods have evolved to document a variety of characteristics in food products including how the intensity of a specific attribute changes over time (Time-Intensity), which specific attribute is dominant at each time during evaluation (Temporal Dominance of Sensations), which attributes are present at each time point during evaluation (Temporal Check-All-That-Apply), and many others (Temporal Order of Sensations, Attack-Evolution-Finish, and Temporal Ranking). In addition to documenting the evolution of temporal methods, this review considers the selection of an appropriate temporal method based on the objective and scope of research. When choosing a temporal method, researchers should also consider the selection of panelists to perform the temporal evaluation. Future temporal research should focus on validation of new temporal methods and explore how methods can be implemented and improved to add to the usefulness of temporal techniques for researchers.}, journal={JOURNAL OF FOOD SCIENCE}, author={Keefer, Heather R. M. and Rovai, Dominic and Drake, MaryAnne}, year={2023}, month={Feb} }
 @article{liu_keefer_watson_drake_2023, title={Consumer perception of whole watermelons}, ISSN={["1750-3841"]}, DOI={10.1111/1750-3841.16843}, abstractNote={There are many varieties of watermelons, providing distinct external and internal sensory attributes. This study used an online survey (n = 700) and focus groups (n = 25) to investigate consumer perception of whole watermelons. Rind color, sound of the melon, size, and price were the most important attributes for consumers when selecting a whole watermelon. Freshness was the most important whole watermelon characteristic, and watermelon freshness/quality was driven by sweetness, crispness, and juiciness. Consumers preferred seedless watermelons that had a light rind with dark green stripes, red flesh, an oval/oblong shape, firm and crisp flesh, a weight of approximately 2.2-5.5 kg, and labeling that described them as fresh, juicy, and sweet. Two consumer clusters were identified from quantitative survey data and were also representative of focus group participants: value consumers and watermelon enthusiasts. Watermelon enthusiasts were differentiated by a higher value for claims including local, product of USA, sustainably farmed, and organic. Watermelon purchase is quality driven: consumers will pay more for guaranteed sweetness and crispness. PRACTICAL APPLICATION: The ideal watermelon for all consumers is one that is dark green with stripes, is medium sized and oblong in shape, has a minimal rind-to-flesh ratio, and boasts dark, vibrant red flesh that is sweet, crisp, and juicy. All consumers want a better guarantee on watermelon quality because it is hard to predict sensory quality when selecting a melon. This study demonstrated the intrinsic and external drivers of liking for fresh watermelons and summarized a consumer watermelon purchase and consumption journey map that can guide further research and development of watermelons and provide insights on how to increase watermelon sales.}, journal={JOURNAL OF FOOD SCIENCE}, author={Liu, Yaozheng and Keefer, Heather and Watson, Megan and Drake, MaryAnne}, year={2023}, month={Nov} }
 @article{keefer_racette_drake_2023, title={Factors influencing consumer motivations for protein choice}, ISSN={["1750-3841"]}, DOI={10.1111/1750-3841.16805}, abstractNote={This study evaluated the factors that motivate US consumers (18-65 years) to choose protein products derived from specific protein sources. An online survey was conducted. Participants who purchased protein products (n = 673) were shown agree/disagree questions, along with maximum difference (MaxDiff), constant sum, and Kano questions on factors surrounding protein choice. Last, follow-up qualitative interviews were conducted with 51 survey participants to further investigate consumer motivations behind protein choice. Survey participants conceptually desired a protein product or protein-fortified food that was a good source of protein, tasted great, and was healthy. Three clusters of consumers with distinct motivations for protein purchases were identified. Cluster 1 (C1) consumers (n = 176) desired plant-based, environmentally friendly products and valued sustainability label claims more than flavor/taste. Cluster 2 (C2) consumers (n = 271) were nutritionally conscious and desired high-protein healthy products that were also high in vitamins/minerals. Cluster 3 (C3) consumers (n = 226) showed the most loyalty to the products they currently purchased and were also most willing to try new products based on the recommendations. Cluster 1 consumers placed importance on protein sources, while C2 valued price most and C3 gave the highest value to flavor. In side-by-side protein comparisons, plant-based proteins were considered superior to dairy proteins in sustainability, health, ethics, and digestibility, while both protein types were at parity for naturalness, satiety, and taste across all consumers, but differences were documented among consumer clusters. Results from this study demonstrate that there are many different motivations for consumers to purchase protein products. These motivations can be applied to consumer education as well as the strategic positioning of protein products. Practical Application: This study investigated consumer perception of different protein types and the drivers of choice for protein types among distinct consumer groups. Further application of findings from this study may help guide the development and formulation of new products with a diverse range of protein sources.}, journal={JOURNAL OF FOOD SCIENCE}, author={Keefer, Heather and Racette, Clara and Drake, Maryanne}, year={2023}, month={Nov} }
 @article{keefer_sipple_carter_barbano_drake_2022, title={Children's perceptions of fluid milk with varying levels of milkfat}, volume={105}, ISSN={["1525-3198"]}, DOI={10.3168/jds.2021-20826}, abstractNote={Schools participating in federal meal programs are limited to serving skim or low-fat (≤1%) flavored and unflavored milk. Few studies have directly addressed child perceptions and preferences for milk containing different amounts of milkfat. The objective of this study was to determine whether children can differentiate between flavored and unflavored fluid milk containing varying levels of milkfat and whether preferences for certain levels of milkfat exist. Flavored and unflavored milks containing 4 different percentages of milkfat (≤0.5, 1, 2, and 3.25%) were high-temperature, short-time processed, filled into half-gallon light-shielded milk jugs, and stored at 4°C in the dark. Milks were evaluated by children (ages 8-13 yr) following 7 d at 4°C. Acceptance testing and tetrad difference testing were conducted on flavored and unflavored milks with and without visual cues to determine if differences were driven by visual or flavor or mouthfeel cues. Child acceptance testing (n = 138 unflavored; n = 123 flavored) was conducted to evaluate liking and perception of selected attributes. Tetrad testing (n = 127 unflavored; n = 129 flavored) was conducted to determine if children could differentiate between different fat levels even in the absence of a difference in acceptance. The experiment was replicated twice. When visual cues were present, children had higher overall liking for 1% and 2% milks than skim for unflavored milk and higher liking for chocolate milks containing at least 1% milk fat than for skim. Differences in liking were driven by appearance, viscosity, and flavor. In the absence of visual cues, no differences were observed in liking or flavor or mouthfeel attributes for unflavored milk but higher liking for at least 1% milk fat in chocolate milk compared with skim was consistent with the presence of visual cues. From tetrad testing, children could visually tell a difference between all unflavored pairs except 2% versus whole milk and could not detect consistent differences between milkfat pairs in the absence of visual cues. For chocolate milk, children could tell a difference between all milk fat pairs with visual cues and could tell a difference between skim versus 2% and skim versus whole milk without visual cues. These results demonstrate that in the absence of package-related flavors, school-age children like unflavored skim milk as well as milk with higher fat content in the absence of visual cues. In contrast, appearance as well as flavor and mouthfeel attributes play a role in children's liking as well as their ability to discriminate between chocolate milks containing different amounts of fat, with chocolate milk containing at least 1% fat preferred. The sensory quality of school lunch milk is vital to child preference, and processing efforts are needed to maximize school milk sensory quality.}, number={4}, journal={JOURNAL OF DAIRY SCIENCE}, author={Keefer, H. M. and Sipple, L. R. and Carter, B. G. and Barbano, D. M. and Drake, M. A.}, year={2022}, month={Apr}, pages={3004–3018} }
 @article{keefer_harwood_castura_drake_2022, title={Temporal ranking for characterization and improved discrimination of protein beverages}, ISSN={["1745-459X"]}, DOI={10.1111/joss.12751}, abstractNote={Abstract We propose a new temporal sensory method called temporal ranking (TR) in which assessors indicate and rank the three most noticeable sensations at every time point. The TR method was compared to temporal‐check‐all‐that‐apply (TCATA) in two trained‐panel studies, one study involving six ready‐to‐mix (RTM) protein beverages and one study involving seven ready‐to‐drink (RTD) protein beverages. In each study, the same attributes were used in both methods; six attributes were evaluated for RTMs and 10 attributes for RTDs. A trained sensory panel ( n = 10) completed TCATA and temporal ranking (TR) training exercises, then evaluated each beverage in triplicate using each method in a replicated balanced randomized design. To evaluate each temporal method (TR and TCATA), each test beverage was compared with the sucrose‐ or sucralose‐sweetened control beverage within each study (RTM and RTD). Although results from TR and TCATA often coincided, TR better differentiated the protein beverage formulations on more sensory attributes and detected differences between the test and control beverages ( p < .05) when TCATA did not. Overall, TR was found to be more sensitive in detecting sensory differences than TCATA, and thus could improve the guidance for the development and formulation of foods. Practical applications This study proposes a new temporal method, temporal ranking, which has assessors continuously rank the three most noticeable attributes when evaluating a beverage. Temporal ranking data can give improved guidance, especially for products that might have side flavors, such as natural nonnutritive sweeteners or alternative protein sources. Further application of findings and methodologies from this study may help guide development and formulation of foods.}, journal={JOURNAL OF SENSORY STUDIES}, author={Keefer, Heather M. and Harwood, Will S. and Castura, John C. and Drake, MaryAnne}, year={2022}, month={May} }
 @article{keefer_harwood_ennis_drake_2021, title={The effect of carrier on consumer liking of soy sauce}, ISSN={["1745-459X"]}, DOI={10.1111/joss.12700}, abstractNote={Abstract Soy sauce may be consumed as an ingredient, a marinade, or as a compliment to sushi. The objective of this study was to determine the role of carrier in the context of consumer liking and differentiation of soy sauces. A trained descriptive analysis panel ( n = 8) documented aromatics, basic tastes, and mouthfeel factors of 27 different soy sauces. Ten representative soy sauces were selected for consumer evaluation. Soy sauces were presented on meatballs, cucumber sushi rolls, and neat in three separate sessions. Within each session, consumers ( n = 121) reported overall liking for each soy sauce. Overall liking scores were evaluated by two‐way analysis of variance (soy sauce × context) and landscape segmentation analysis (LSA) was applied to visualize consumer ideal points for each context. Soy sauce liking scores were highest for meatballs and lowest for neat evaluation ( p < .05). Context and soy sauce impacted liking (p < .05), but there was no interaction ( p > .05), and liking scores were generally consistent, regardless of context. Drivers of liking determined via LSA differed slightly among the various contexts tested, and there was evidence that consumer ideals within a product space shifted in different contexts. Practical Applications Selection of a carrier for a consumer taste test can be time‐consuming and expensive. This study demonstrates that consumers can evaluate soy sauces neat and provide the same directional information as if the consumers evaluated the soy sauces with a carrier.}, journal={JOURNAL OF SENSORY STUDIES}, author={Keefer, Heather R. M. and Harwood, William S. and Ennis, Daniel and Drake, MaryAnne}, year={2021}, month={Aug} }
 @article{keefer_nishku_gerard_drake_2020, title={Role of sweeteners on temporality and bar hardening of protein bars}, volume={103}, ISSN={["1525-3198"]}, DOI={10.3168/jds.2019-17995}, abstractNote={Protein bars are one product that meet consumer demands for a low-carbohydrate, high-protein food. With such a large market for protein bars, producers need to find the correct texture and sweetness levels to satisfy consumers while still delivering a high-protein, low-carbohydrate bar. In the bar industry, bar hardening is a major concern, and currently the effects of non-nutritive sweeteners on bar hardening is unknown. Due to the negative implications of bar hardening, it is important to investigate the sweetener-protein relationship with bar hardening. The objective of this study was to characterize the effects of sweetener and protein source on flavor, texture, and shelf life of high-protein, low-carbohydrate bars. The iso-sweet concentration of sweeteners (sucralose, sucrose, monk fruit, stevia, and fructose) in pea protein (PP), milk protein (MP) and whey protein isolate (WPI) bars were established using magnitude estimation scaling and 2-alternative forced-choice testing. Descriptive analysis and temporal check-all-that-apply methods were then applied to determine flavor and temporal differences between the protein bars. Finally, an accelerated shelf life study was completed to understand how sweetener and protein types affect the shelf life of protein bars. The 15 protein bars formulated at iso-sweet concentration were all stored at 35°C and 55% humidity for 35 d, and measurements were taken every 7 d, beginning at d 1 (d 1, 7, 14, 21, 28, and 35). Bars made with MP required significantly less sweetener, compared with PP and WPI, to reach equal sweetness (P < 0.05). Bars sweetened with stevia or monk fruit had distinct bitter and metallic tastes, and sucralose had a low metallic taste. Bars made with WPI were the most cohesive, and PP and WPI bars were more bitter and metallic compared with MP bars (P < 0.05). Bars made with WPI and fructose were initially the hardest, but after d 14 they scored at parity with PP sucrose. There were no significant differences among bars in terms of hardness by d 21. Bars made with WPI were consistently denser at all time points than bars made with PP or MP. Bars made with PP were the driest and least cohesive and had the fastest rate of breakdown in the study. Non-nutritive sweeteners did not have a negative effect on bar hardness in low-carbohydrate, high-protein bars. Findings from this study can be applied to commercially produced protein bars for naturally sweetened bars with different protein types without negative effects on protein bar texture.}, number={7}, journal={JOURNAL OF DAIRY SCIENCE}, author={Keefer, H. R. M. and Nishku, S. and Gerard, P. D. and Drake, M. A.}, year={2020}, month={Jul}, pages={6032–6053} }
 @article{mccain-keefer_meals_drake_2020, title={The sensory properties and consumer acceptance of cold brew coffee}, volume={35}, ISSN={["1745-459X"]}, DOI={10.1111/joss.12604}, abstractNote={Abstract}, number={6}, journal={JOURNAL OF SENSORY STUDIES}, author={McCain-Keefer, Heather R. and Meals, Stephanie and Drake, MaryAnne}, year={2020}, month={Dec} }