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Document Type

Thesis - University Access Only

Award Date

2001

Degree Name

Master of Science (MS)

Department / School

Dairy Science

First Advisor

Rajiv I. Dave

Abstract

Mozzarella cheeses were made from cows' milk standardized to 1.6% fat. There were two different types of starter cultures comprising only Streptococcus thermophilus. (SC) or a combination of Streptococcus thermophilus and Lactobaci/lus helveticus (MC). Rennet or Cryphonectria parasitica protease at two different levels (1 X and 6X) were used as the coagulating enzymes. MC cheeses had higher moisture and protein contents and lower fat content. Cheeses made with rennet showed a greater hydrolysis of αS- casein, whereas, cheeses made with sure curd showed a greater hydrolysis of β-casein. The extent of hydrolysis was found to be greater in MC cheeses at 6X level of coagulating enzyme. Maximum hydrolysis of αS- casein was ~70% in case of MC cheeses made with 6X rennet, but that of β-casein was -50% for MC cheeses made with 6X sure curd. Meltability of cheese as measured by modified Schreiber test showed significant differences for cheeses made with different type of cultures, and also for different types and level of coagulating enzymes. However, when the meltability was measured by Creep test, it was found that the differences were not significant between the types of coagulating enzyme. This indicated that, even if the cheeses soften to a similar extent, their flowability could be different. Meltability as measured by the Schreiber test was correlated best to the hydrolysis of β-casein, which was comparable with soluble nitrogen, but correlated least to αS -casein. Values of elastic modulus (G') and viscous modulus (G") decreased with the age of the cheese and the decrease was higher in MC cheeses compared to SC cheeses. MC cheeses had higher counts for both lactobacilli and streptococci. Higher number of starter bacteria in MC cheeses might also have contributed to their better meltability through bacterial channel similar to the fat-serum channels.

Library of Congress Subject Headings

Mozzarella cheese
Food -- Fat content

Description

Includes bibliographical references (pages 49-57)

Format

application/pdf

Number of Pages

100

Publisher

South Dakota State University

Rights

In Copyright - Non-Commercial Use Permitted
http://rightsstatements.org/vocab/InC-NC/1.0/

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