Effect of brine composition and brining temperature on cheese physical properties in Ragusano cheese

摘要

Composition and physical properties of cheeses are influenced by temperature, salt, and calcium concentration of brine. This work aimed to examine conditions of brine under which the cheese matrix contracts or expands in absence of restrictions imposed by surface rind development during overnight block formation. Three experimental 4-kg blocks of Ragusano cheese were produced at 3 different stretching temperatures (70, 80, and 90℃) and cut into pieces weighing approximately 40 to 50 g. One piece from each was chemically analyzed at time 0. All other pieces were measured for weight and volume and placed in plastic bags containing 300 mL of different brine solutions (2% NaCl with 0.1% Ca; 10% NaCl with 0, 0.1, 0.2, or 0.4% Ca; 18% NaCl with 0.1% Ca; and 26% NaCl with 0.1% Ca) at 3 different temperatures (4, 12, and 20℃). After 24 h of brining, the cheeses were analyzed for weight, volume, chemical, and microstructural changes. Salt concentration in brine significantly influenced composition, weight, and volume of the cheeses after brining. Salt concentration was inversely related to cheese volume and weight. Changes in weight caused by altering the brining temperature were sufficient to reach statistical significance, and statistically significant volume changes were induced by brining temperature and its interaction with salt content. The highest volume increase (30%) occurred in the cheese stored in the 2% NaCl brine at the coldest temperature, whereas the greatest volume decrease was recorded in cheeses brined in the 26% NaCl brine. Composition was not affected by brining temperature. Calcium concentration did influence weight, volume, and composition, except on a fat-on-dry-basis. When cheeses were brined without added calcium, cheese volume and weight increased at all temperatures. At high calcium levels (0.4%), synere-sis occurred and volume decreased, especially at 20℃ (-16.5%). Microstructural investigation with porosity measurement confirmed weight and volume changes.