The Impact of Agglomeration on Flavor and Flavor Stability of Whey Proteins

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Title: The Impact of Agglomeration on Flavor and Flavor Stability of Whey Proteins
Author: Zevchak, Sarah Elizabeth
Advisors: Dr. E. Allen Foegeding, Committee Member
Dr. Lynn Turner, Committee Member
Dr. MaryAnne Drake, Committee Chair
Abstract: Descriptive sensory analysis of freshly produced WPC80 and WPI has documented a variety of flavors in these products including sweet aromatic, cardboard/wet paper, pasta water, brothy, cucumber, and soapy flavors, astringent mouthfeel and bitter taste. Concurrent volatile analysis has revealed an array of heat-induced and lipid and protein oxidation compounds. The purported shelf life of WPC80 and WPI varies from 12 to 18 months depending on the supplier. However, to our knowledge, no studies have addressed stability of WPC80 or WPI or the impact of agglomeration on the flavor and flavor stability of WPC80 and WPI. In this study, agglomerated (re-wet and single pass) and non-agglomerated samples of WPC80 and WPI from different facilities were analyzed for flavor and selected physical properties over the course of fifteen months. Descriptive sensory analysis and volatile analysis were conducted every 2 months. Samples were tested every six months for solubility, bulk volume, dispersibility, moisture, and color (L,a,b). Proximate analysis was conducted at time zero. Consumer acceptance tests were conducted on representative samples after 0, 6, 9, 12 and 15 months storage using vanilla protein shakes and peach flavored beverages with WPC80 and fruit flavored clear acidified beverages with WPI. Agglomerated powders displayed higher bulk volume and dispersibility than their non-agglomerated counterparts. Solubility, bulk volume, dispersibility, moisture and color did not significantly change with storage time. Higher intensities of lipid oxidation flavors (cardboard, raisin/brothy, cucumber, and fatty) were noted in agglomerated powders compared to control powders (p<0.05). Sensory results were confirmed by volatile analysis results which showed increased formation of aldehydes and ketones in agglomerated products compared to control powders (p<0.05). Acceptance tests with protein beverages revealed few differences in consumer acceptance between agglomerated and non-agglomerated whey proteins or between fresh versus stored whey proteins although trained panelists documented consistent differences. Agglomeration or agglomeration with lecithin decreased the storage stability of whey proteins. These results indicate that the optimum shelf life at 21C for non-agglomerated powders is between 12-15 months and 8-10 months for agglomerated powders.
Date: 2007-10-25
Degree: MS
Discipline: Food Science
URI: http://www.lib.ncsu.edu/resolver/1840.16/1610


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