Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Dairy and Food Science

First Advisor

Lloyd E Metzger


Cheddar cheese is a commodity and a top-selling cheese in the United States. Enhanced flavors of cheddar cheese requires aging, which will allow proteolysis increase. Proteolysis is the most complex process that happens in cheese manufacturing and can be difficult to control because of environmental factors and compositional characteristics. The ripening process, which is the most timely and costly procedure in cheese manufacturing, can also be unpredictable when aspects, such as cheese composition, are changed. The coagulant is responsible for the first stage in proteolysis, which will produce large peptides. Small peptides are subsequentially produced during the second stage by starter bacteria and non-starter lactic acid bacteria. Cheddar cheese was analyzed for composition and amount of proteolysis in this study. Analytical methods were used to determine composition including fat, moisture, salt, and protein. The level of proteolysis in the cheese was analyzed by the Kjeldahl fractionation method, and two different fractions were examined: soluble N percent of TN at pH 4.6, soluble N in 12% TCA as a percent of TN. Small peptides increased over time, using TCA separation, and large and small peptides increased over time, using pH 4.6 separation. Samples that only had a greater amount of fat had slower proteolysis. Over the length of the study the expected composition of Cheddar cheese had a slower rate of proteolysis for TCA-soluble N as a % of TN, compared to Cheddar cheese that had higher low S/M, low salt and low pH. Cheese samples with a greater amount of fat and lower amount of moisture had an increased amount of TCA-soluble N as a % of TN. Samples that had a greater amount of fat, lower moisture and a pH below 5.06 or above 5.15 had the most amount of primary and secondary proteolysis. Process cheese is affected by its ingredients and the natural cheese. A correlation from the current study was as proteolysis increased, the apparent viscosity and hardness decreased. The meltability increased when the proteolysis increased. Compositional factors of the natural cheese that contributed to the functionality of the PC were pH, S/M and ash minus salt.

Library of Congress Subject Headings

Cheddar cheese -- Composition.
Process cheese.

Number of Pages



South Dakota State University



Rights Statement

In Copyright