@article{li_lopetcharat_qiu_drake_2015, title={Sugar reduction of skim chocolate milk and viability of alternative sweetening through lactose hydrolysis}, volume={98}, ISSN={["1525-3198"]}, DOI={10.3168/jds.2014-8490}, abstractNote={Milk consumption by Americans has not met the standards of the Dietary Guidelines for Americans. Chocolate milk can improve milk consumption, especially by children, due to its color and taste. However, the high sugar content of chocolate milk is a cause for concern about its healthfulness, resulting in its removal from some school lunch programs. It is important to reduce the sugar content of chocolate milk and still maintain acceptability among consumers. It is also important to investigate other natural alternatives to sweetening. The objectives of this study were to identify the different sweetness intensity perceptions of sucrose in water and various dairy matrices, to identify the acceptable reduction in sweet taste for chocolate milk for both young adults (19-35 yr) and children (5-13 yr), and to determine if lactose hydrolysis is a viable alternative. Threshold and power function studies were used to determine the benchmark concentration of sucrose in chocolate milk. The acceptability of sugar reduction from the benchmark concentration for both young adults and children and the acceptability of lactose hydrolyzed chocolate milk (4°C for 24 h) with added lactose for young adults were evaluated. Acceptability results demonstrated that sugar reduction in chocolate milk is possible for both young adults and children as long as it does not exceed a 30% reduction (from 205 mM). Lactose hydrolysis of added lactose was used to achieve the sweetness of sucrose in chocolate milk but required >7.5% (wt/vol) added lactose, which contributed undesirable calories, indicating that lactose hydrolysis may be more suitable for other dairy beverages that require less added sugar. The findings of this study demonstrate consumer acceptance of reduced-sugar chocolate milk and a possible way to use lactose hydrolysis in dairy beverages.}, number={3}, journal={JOURNAL OF DAIRY SCIENCE}, author={Li, X. E. and Lopetcharat, K. and Qiu, Y. and Drake, M. A.}, year={2015}, month={Mar}, pages={1455–1466} }
 @article{qiu_smith_foegeding_drake_2015, title={The effect of microfiltration on color, flavor, and functionality of 80% whey protein concentrate}, volume={98}, DOI={10.3168/jds.2014-9174}, abstractNote={The residual annatto colorant in fluid Cheddar cheese whey is bleached to provide a neutral-colored final product. Currently, hydrogen peroxide (HP) and benzoyl peroxide are used for bleaching liquid whey. However, previous studies have shown that chemical bleaching causes off-flavor formation, mainly due to lipid oxidation and protein degradation. The objective of this study was to evaluate the efficacy of microfiltration (MF) on norbixin removal and to compare flavor and functionality of 80% whey protein concentrate (WPC80) from MF whey to WPC80 from whey bleached with HP or lactoperoxidase (LP). Cheddar cheese whey was manufactured from colored, pasteurized milk. The fluid whey was pasteurized and fat separated. Liquid whey was subjected to 4 different treatments: control (no bleaching; 50°C, 1 h), HP (250 mg of HP/kg; 50°C, 1 h), and LP (20 mg of HP/kg; 50°C, 1 h), or MF (microfiltration; 50°C, 1 h). The treated whey was then ultrafiltered, diafiltered, and spray-dried to 80% concentrate. The entire experiment was replicated 3 times. Proximate analyses, color, functionality, descriptive sensory and instrumental volatile analysis were conducted on WPC80. The MF and HP- and LP-bleached WPC80 displayed a 39.5, 40.9, and 92.8% norbixin decrease, respectively. The HP and LP WPC80 had higher cardboard flavors and distinct cabbage flavor compared with the unbleached and MF WPC80. Volatile compound results were consistent with sensory results. The HP and LP WPC80 were higher in lipid oxidation compounds (especially heptanal, hexanal, pentanal, 1-hexen-3-one, 2-pentylfuran, and octanal) compared with unbleached and MF WPC80. All WPC80 had >85% solubility across the pH range of 3 to 7. The microstructure of MF gels determined by confocal laser scanning showed an increased protein particle size in the gel network. MF WPC80 also had larger storage modulus values, indicating higher gel firmness. Based on bleaching efficacy comparable to chemical bleaching with HP, flavor, and functionality results, MF is a viable alternative to chemical or enzymatic bleaching of fluid whey.}, number={9}, journal={Journal of Dairy Science}, author={Qiu, Y. and Smith, T. J. and Foegeding, E. A. and Drake, M. A.}, year={2015}, pages={5862–5873} }