Factors Regulating Shreddability of Cheese

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Title: Factors Regulating Shreddability of Cheese
Author: Childs, Jessica Leigh
Advisors: E. Allen Foegeding, Committee Chair
Len Stefanski, Committee Member
Christopher Daubert, Committee Member
Abstract: Shredding cheese is a way to increase the functionality of the cheese by allowing it to melt more evenly and easily. A high quality shred would ideally be one that is uniformly cut with little variation from shred to shred. Some, but not all, factors affecting the shred quality are cheese composition, temperature at which cheese is shred, shredding equipment and properties of the cheese including rheological and adhesive properties. In this experiment, three sets of cheeses were evaluated to determine factors that affect shred quality. The first set of cheeses was made up of three commercial cheeses, Monterey Jack, mozzarella and process. The second set of cheeses, Experimental Cheese Set A, was made up of three mozzarella cheeses with varying levels of protein and fat and constant moisture content. The third set of cheese, Experimental Cheese Set B, was made up of four cheeses formulated to have varying levels of moisture and calcium. A shred distribution of long shreds, short shreds and fines was obtained by shredding blocks of cheese in a food processor under a constant load of 4 Kg. A probe tack test was used to directly measure adhesion of the cheese to a stainless steel surface. Adhesion is related to surface energy and rheological properties. Surface energy was determined by measuring the contact angle that is formed when liquids are dropped on the cheese surface. Once the contact angles were measured, the surface energy of the cheese was determined based upon equations derived from the Young equation. Rheological characterization was done by creep and recovery tests. Creep and recovery data allowed for calculating the maximum and initial compliance and retardation time. Tests for commercial cheeses were done at 4&deg;C, 12&deg;C and 20&deg;C. Tests for the second and third experiments were carried out on 2, 7, 14, 21 and 28 days after cheese processing and properties were measured at 7&deg;C. For the commercial cheeses, two defects in shredding were observed: production fines and adhesion to the blade. Mozzarella produced the most fines during shredding and had the highest maximum compliance, implying that the softest cheese produced the most fines during shredding. Monterey Jack and process cheeses had the greatest amount of cheese adhere to the blade as well as the highest tack energy. This indicated that a relationship exists between tack energy and amount cheeses adhered to the blade. In addition, the tack energy increased as the maximum compliance increased, implying that the softer cheese had a higher tack energy. For Experimental Cheese Set A, the defect observed in shredding was production of fines; there was very little adhesion to the blade. The cheese that produced the most fines was the cheese with the highest fat and lowest protein content. This cheese also had the highest compliance of the three cheeses tested. In addition, the softest cheese also had the highest tack energy of the three cheeses. The cheese that had the highest tack energy produced the most fines when shred. From this experiment, the softer cheeses (higher maximum compliance) had the greatest tack energy and the most fines produced during shredding. Cheeses in Experimental Cheese Set B also showed production of fines as the main defect during shredding. The cheese with the highest tack energy produced the most fines during shredding. The maximum compliance also showed to have an effect on the fines produced during shredding. Since the moisture content of these cheeses was controlled, it was possible to see that the moisture content had a significant effect (p<0.05) on the amount of fines produced during shredding. The higher moisture cheeses had more fines produced.
Date: 2004-09-22
Degree: MS
Discipline: Food Science
URI: http://www.lib.ncsu.edu/resolver/1840.16/890

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