Date of Award:

6-21-2012

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Nutrition, Dietetics, and Food Sciences

Advisor/Chair:

Donald J McMahon

Abstract

The rate and extent of syneresis (whey expulsion) strongly affects cheese composition and quality. During salting, curd syneresis is influenced by the combined effect of both osmotic pressure and protein hydration. Our objective is to examine how cheese composition and whey expulsion are influenced by dry salting curd at various intervals, levels, applications, and potassium chloride (KCl) substitution, or change in calcium or sodium level in test solution (i.e., whey-brine). Four sets of unsalted fresh Cheddar curds were salted with different methods, with at least 3 replicates of each set on separate days. Set A was salted with 30 g/kg NaCl over 3 applications, either 5 or 10 min apart. Set B was salted with 30, 25, and 20 g/kg NaCl over 3 applications 5 min apart. Set C was salted with 20 g/kg NaCl using 1, 2, or 3 applications. Set D received salt consisting of a 2:1 molar ratio of NaCl and KCl over 3 applications 5 min apart. Whey was collected every 5 or 10 min until 30 or 40 min after the start of salting and subsequently pressed for 3 h. Using 10-min intervals delayed whey syneresis but after pressing there was no significant influence on final cheese composition. Decreasing salt levels significantly reduced the amount of whey expelled prior to pressing and resulted in cheeses with higher moisture and slightly lower pH. Adding salt over different applications did not significantly affect cheese composition. Partial substitution with KCl did not affect the amount of whey expelled or cheese moisture composition. Salted milled Cheddar cheese curd was immersed at 22°C for 6 or 18 h in test solution, with the addition of 1, 5, 10, or 20 g/L calcium, and 15 g/L salt. After immersion, curd weight change, moisture, pH, sodium, serum calcium and total calcium levels were measured. When calcium levels in solution increased, curd moisture, pH, and weight gain decreased while serum and total calcium levels increased significantly. Similarly, unsalted milled Cheddar cheese curds were immersed at 22°C for 6 h in test solution with 30, 60, 90, or 120 g/L salt in addition to 6 g/L calcium. The salt level in solution was inversely proportional with weight change, moisture, and salt level of curd.

Comments

This work made publicly available electronically on July 30, 2012.

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