Document Type

Thesis - Open Access

Award Date

2020

Degree Name

Master of Science (MS)

Department / School

Dairy Science

First Advisor

Lloyd Metzger

Keywords

Cheese Model System, Low Temperature Browning, Parmesan

Abstract

In cold temperature storage, Parmesan cheese can develop an undesirable browning defect. Certain pyrazine compounds converted from methylglyoxal have been identified and associated with the brown pigmentations in Parmesan cheese samples. This study focused on creating a cheese model system to study variables that caused browning and variables that helped reduce or alleviate browning. The cheese making steps for the cheese model system were monitored by measuring pH and TA and the final composition for % fat, % moisture, % salt and pH. Additionally, the cooling curve was studied to ensure all wheels of cheese made were cooled similarly. Cheese made in the experiment were then used in a slurry as part of the cheese model system to test variables such as aging temperature, heat abuse, addition of NSLAB, addition of adjuncts, addition of galactose, addition of methylglyoxal and modified %salt and pH. This study identified variables that contributed to browning which included: aging temperature (55°F), addition of methylglyoxal, NSLAB addition, heat abuse and time. Increased browning was observed over time, the most after 3 months, at 55°F in the presence of methylglyoxal and heat abuse. These findings were verified by testing these variables at different ages using a colorimeter. The variables studied to understand how to reduce browning included addition of NSLAB (Lb. helveticus), addition of adjuncts (lb. plantarum and Lc. lactis diacetylactis) and modified environment of high %salt and low pH. The cheese model system had a % salt of 2.19 and a pH of 5.60 which was modified to 3.00% for high salt and 5.20 pH, all samples were aged at 55°F. Reduction of browning was achieved using both adjuncts and modified environments of high salt and low pH. The greatest reduction in browning was observed when Lb. helveticus and Lb. plantarum were added together as a treatment and had a small Delta E (color change) of 0.92. The adjunct, Lc. lactis diacetylactis also reduced browning, average Delta E of 1.89 in the presence of Lb. helveticus, high %salt and low pH. The most effective way to reduce browning was achieved using adjuncts and modified environments of high salt and low pH.

Library of Congress Subject Headings

Parmesan cheese -- Analysis.
Parmesan cheese -- Cooling.
Parmesan cheese -- Storage.

Format

application/pdf

Number of Pages

150

Publisher

South Dakota State University

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Rights Statement

In Copyright