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Document Type

Thesis - University Access Only

Award Date

2015

Degree Name

Master of Science (MS)

Department / School

Dairy Science

First Advisor

Hasmukh A. Patel

Keywords

skim milk concentrates, viscosity, preheat treatment, pH, whey protein, heat stability, hydrogen peroxide

Abstract

The research findings presented in this thesis are grouped into two major sections. The first part of this thesis is focused on understanding the role of milk protein interactions in tailoring the viscosity of skim milk concentrate (SMC), while the second part is focused on understanding the role of protein interaction in heat stability of whey proteins. The objective of the part 1 (chapter 3) was to control the increase in viscosity of concentrated skim milk with a total solids (TS) >50% by understanding the role of protein interactions and mechanisms of viscosity increase as affected by preheating temperature (80°C and 90°C), pH of milk at preheating as well as pH of milk before concentration (6.5 and 6.7). There were two major findings (i) lower amount of whey protein denaturation and their interactions with casein in the milk preheated at 80°C compared to 90°C and (ii) lower voluminosity of the casein micelle in the skim milk adjusted at pH 6.5 before concentration compared to pH 6.7 yielded SMC with lower viscosity. These lower viscosity values were independent of pH at preheating (6.5 and 6.7), indicating that the difference in the amount of denatured serum proteins in SMC did not play significant role in the viscosity of SMC. The main objective of part 2 (chapter 4) was to understand the role of protein interactions in improving the heat-stability of concentrated solution of whey protein isolate (WPI). The specific role of hydrogen peroxide (H2O2) process in reducing denaturation, aggregation and gelation as well as improving the heat stability of whey proteins was studied. The results displayed that the hydrogen peroxide can alter the pathways related to intermolecular disulfide interactions of whey protein denaturation, aggregation and gelation, which can play a significant role in improving the heat-stability of WPI solutions.

Library of Congress Subject Headings

Milk proteins Skim milk Milk -- Analysis Viscosity Whey

Description

Includes bibliographical references

Format

application/pdf

Number of Pages

137

Publisher

South Dakota State University

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Rights Statement

In Copyright