Off-campus South Dakota State University users: To download campus access theses, please use the following link to log into our proxy server with your South Dakota State University ID and password.

Non-South Dakota State University users: Please talk to your librarian about requesting this thesis through interlibrary loan.

Document Type

Dissertation - University Access Only

Award Date


Degree Name

Doctor of Philosophy (PhD)


Dairy Science

First Advisor

Lloyd Ernst Metzger


Functional ingredients from naturally occurring food biopolymers are a trend catching up amongst food and beverage developers. This is driven by the demand of consumers for clean label ingredient listings on products. The clean label trend is extending into the yogurt market (acid gel) with consumers demanding hydrocolloids, stabilizers or thickeners are purged from ingredient listings. Substituting hydrocolloids in food systems especially yogurts could mean compromising on rheological properties and water holding capacities. However, structure functionality relationship of naturally occurring biopolymer caseins in milk can be exploited to overcome this foreseen loss of product characteristics. The objective of this research was to explore clean label processes that could potentially eliminate the use of hydrocolloids in acid milk gels. Partially demineralized proteins from CO2 treated milk protein concentrate was used to substitute partly proteins in formulations of acid gels. There was a significant increase in the G' (p (p<0.05) of acid gels with a rise in partially demineralized protein substitution. Additionally, the fundamental mechanism of kosmotropic agents like lactose in improving water holding capacity (WHC) and G' of acid gels was elucidated. The acid gelation properties of MPC dispersions containing increased concentration of lactose were modified by influencing thermodynamically driven hydrophobic interactions of the caseins. MPC35 dispersions standardized to 11.2 % (w/w) lactose had the highest G' and WHC values and MPC90 dispersions not adjusted for lactose had the lowest G' and WHC values. In yet another study, ionic strength and Ca2+ activities of dispersions were varied using UF and its influence on the acid gelation properties of high protein acid gels were investigated. Protein interactions were manipulated in these dispersions, and a system was developed where the excessive buildup of viscosity was avoided. In another study, partially demineralized proteins were used to fortify milk in the manufacture of Greek style yogurts. In conjunction with the process of hydrodynamic cavitation (HC), Greek-style yogurts with improved WHC and flow profiles, acidity levels and microstructure similar to strained commercial Greek yogurts were produced. Overall the findings of the study offered clean label solutions for the manufacture of acid milk gels.

Library of Congress Subject Headings

Dairy products--Labeling


Includes bibliographical references (pages 168-171)



Number of Pages



South Dakota State University


In Copyright - Educational Use Permitted