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Gagan Deep

Document Type

Thesis - University Access Only

Award Date

2012

Degree Name

Master of Science (MS)

Department / School

Dairy Science

First Advisor

Dr. Ashraf Hassan

Second Advisor

Dr. Lloyd Metzger

Keywords

whey protein concentrate, exopolysaccharide, functionality

Abstract

The objectives of this research were to produce whey protein concentrate (WPC) with modified functionality using exopolysaccharides (BPS) producing cultures and utilize modified WPC to replace egg whites in cake. Two different BPS-producing cultures, Lactococcus lactis ssp. cremoris (JFR) and Streptococcus thermophilus (DP), producing BPS 1 and BPS2 respectively, were used in this study. One BPS-nonproducing commercial cheese culture (DYS 850) was used as control. Whey powder was utilized in this study to eliminate variations from fresh whey. Cultures grown overnight in reconstituted WPC (10 % w/w) were added directly or after overnight cooling (cooled BPS), at 2 % to reconstituted whey (6 % w/w). This gave a level of BPS similar to that found in whey from cheese made with BPS-producing cultures. Whey was then HTST pasteurized at 75 °C for 35 sec and ultrafiltered five times. Ultrafiltered whey (retentate) was spray dried at inlet and outlet air temperatures of 200 °C and 90 °C respectively to obtain WPC. In general the protein solubility of all WPC was higher at pH 7 than at pH 3. Whey protein concentrate containing BPS2 without cooling, WPC containing cooled BPS 1 and WPC containing cooled BPS2 exhibited higher protein solubility (p < 0. 05) as compared to WPC containing no EPS. Also, WPC containing EPS showed lower protein denaturation (p < 0. 05) than that with no E~S. Emulsifying ability of WPC containing EPS was higher (p < 0. 05) than that in control. Addition of EPS to WPC significantly enhanced (p < 0. 05) its· gelling ability. Foam overrun and hydrophobicity of WPC were not affected by addition of EPS. Different types of EPS used in this study modified WPC functionality to varying extents. Functionality of the WPC powders produced was tested in cake making. Control cakes were prepared using egg white powder. Specific gravity ahd viscosity of cake batter did not change when one third of the egg whites powder was replaced with WPC containing EPS. Higher levels of replacement with WPC deteriorated cake batter quality. In conclusion, data obtained from this study shows that EPS modifies WPC functionality. The extent of modification depends upon the type of EPS. Cooling of the fermentate containing EPS prior to its addition to whey further improved the functional properties of the resulting WPC. Further studies will be directed towards understanding the effect of EPS structure and their interaction with whey protein on WPC functionality.

Library of Congress Subject Headings

Whey
Whey products
Microbial exopolysaccharides

Description

Includes bibliographical references (pages 41-53)

Format

application/pdf

Number of Pages

75

Publisher

South Dakota State University

Rights

In Copyright - Non-Commercial Use Permitted
http://rightsstatements.org/vocab/InC-NC/1.0/

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