Quality of yogurt supplemented with whey protein concentrate and effects of whey protein denaturation

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dc.contributor.author Landge, Virendra Laxman
dc.date.accessioned 2009-12-17T14:29:18Z
dc.date.available 2009-12-17T14:29:18Z
dc.date.issued 2009-12-17T14:29:18Z
dc.identifier.uri http://hdl.handle.net/2097/2303
dc.description.abstract Yogurt is a good source of whey proteins, which have been reported to provide positive health benefits. During yogurt manufacture, the yogurt mix receives a heat treatment which pasteurizes the product, denatures the whey proteins affecting their availability, and enhances quality attributes. Thus the objective of this research was to improve the undenatured whey protein content in yogurt. The study was divided in two parts. The first part focused on the effect of pasteurization treatments of yogurt mixes (65 °C for 30 min vs. 90 °C for 10 min) on the yogurt firmness, G’, L*, syneresis and water holding capacity (WHC), and how these properties change as a function of storage. Nonfat dry milk (NFDM) was reconstituted (~11% w/v) pasteurized, cooled, inoculated with yogurt culture, incubated to pH 4.5, stored at 5 °C ±1 and evaluated for various physical and chemical properties on days 1, 15 and 29. The experiment was replicated 3 times and data were analyzed by SAS®. Yogurt samples had a 5-fold difference in whey protein denaturation (WPD) and the greater the WPD the greater the firmness, G’, L* and WHC but lesser the syneresis. During yogurt storage, L*, G’, syneresis and WHC increased. The second part of this research focused on whey protein concentrate (WPC) addition (3%) in yogurt mix combined with two pasteurization treatments (70 °C for 30 min vs. 90 °C for 10 min) to determine their effects on the yogurt quality. Yogurt mixes were formulated using 12.5% NFDM or 9.5% NFDM and 3% WPC and a procedure similar to the previous study was followed. The WPC addition resulted in a yogurt with decreased firmness, G’, WHC but increased syneresis. Yogurt made from mixes pasteurized at 90 °C for 10 min had ~60% WPD and comparable quality attributes regardless of WPC addition. Thus, additional WPC and less WPD in this study resulted in a yogurt with slightly lesser quality attributes but more undenatured whey proteins in the final yogurt. en_US
dc.language.iso en_US en_US
dc.publisher Kansas State University en
dc.subject Set yogurt en_US
dc.subject Whey Protein en_US
dc.subject Whey protein denaturation en_US
dc.subject Texture en_US
dc.subject Syneresis en_US
dc.subject Water holding capacity en_US
dc.title Quality of yogurt supplemented with whey protein concentrate and effects of whey protein denaturation en_US
dc.type Thesis en_US
dc.description.degree Master of Science en_US
dc.description.level Masters en_US
dc.description.department Food Science Institute, Animal Science and Industry en_US
dc.description.advisor Karen A. Schmidt en_US
dc.subject.umi Agriculture, Food Science and Technology (0359) en_US
dc.date.published 2009 en_US
dc.date.graduationmonth December en_US

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