Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)


Dairy Science


A major concern in the cottage cheese industry is the inefficient use of the available milk proteins. Currently, the methods of cottage cheese manufacture convert an average of only 74.9% of the milk proteins into cottage cheese, while the remainder are removed in the by-product whey (43, 56). As protein is the main determinant of both the yield and nutritional value of cottage cheese, if 25% of the available protein is lost to the whey, then potential cottage cheese yield and nutrition have been lost as well. The proteins lost in the whey are mainly -lactalbumin and β-lactoglobulin, which remain soluble during the conditions of cottage cheese manufacture and thus do not become part of the curd (38, 39). Although these proteins have the highest known nutritional value (21, 22, 45, 60, 71), they can be an added expense rather than a benefit to the dairy industry. The proteins as whey solids must either be processed further, disposed of, or both. Processing whey is expensive and difficult because cottage cheese whey is both dilute, 94% water, and highly acid, pH 4.6, (3, 9, 39, 65). Concurrently, the products produced by processing cottage cheese whey such as animal feeds, dried or concentrated products, and fermentation products have a limited and competitive market and are not highly profitable (39, 51). However, disposal is a less attractive and more expensive alternative because whey has a high biochemical oxygen demand (BOD) making it 3 major pollutant requiring high levels of microbial action for treatment (3, 10). Public response to whey as a pollutant has forced the passing of statutes forbidding the disposal of untreated whey into lakes, streams, and rivers. Concurrently, whey disposal in sewage systems has become increasingly expensive (3, 9, 39). The whey protein, as part of the whey, thus present a temperamental enigma and overshadowing dilema to the cottage cheese industry: being the most nutritious proteins known, they remain virtually too unprofitable to process, but too expensive to throw away. Recovery of some of the proteins dissolved in the whey is possible by the use of polyelectrolytes that will precipitate the whey proteins, allowing them to be recovered by centrifugation (25, 28, 33, 34). The substances reported to provide the largest recovery are carboxymethyl cellulose (CMC) and several phosphate compounds such as sodium hexametaphosphate (SHMP). If the procedures for recovering proteins from the whey using polyelectrolytes could be combined with the procedures for manufacturing cottage cheese, then the finished product would include the whey proteins, providing higher yields and nutritional value. The objective of this study was to explore the possibility that polyelectrolytes may increase the yield of cottage cheese by removing proteins from the whey and adding them to the curd. The chosen additives were screened, and then the yields and composition of cottage cheese made by a widely accepted culture procedure (70) were compared with the yield and composition of cottage cheese made from milk containing 0.05 or 0.2 sodium hexamctaphosphatc.

Library of Congress Subject Headings

Cottage cheese
Milk proteins


Includes bibliographical references (pages 56-61)



Number of Pages



South Dakota State University

Included in

Dairy Science Commons