Rheological characterization of the ripening of Port Salut Argentino cheese

VERDINI, RA; RUBIOLO, AC

Valencia, España

Congreso; III Congreso Iberoamericano de Ingeniería de Alimentos; 2001

Texture is one of the important characteristics that determines the nature and the quality of a cheese. In the study of food texture there is a great interest in the analysis of the relation between texture and structure. The objective of our work was to measure texture changes during the ripening of Port Salut Argentino cheese using stress-relaxation curves and to associate rheological parameters with factors that affect the rate and the extent of proteolysis, especially moisture and salt content. Three blocks of cheese were sampled at different ripening time: 1, 6, 13 and 27 days. Cubic pieces of 25 x 25 mm were obtained from two different cheese zones: central zone (25 mm from the center and 25 mm from the surface) and outer zone (80 mm from the center and 5 mm from the surface). Protein, moisture and salt content were determined. Specimens were compressed by a Universal Testing Machine with a 5-kg load cell. Relaxation curves were recorded for 8 minutes. Compression ratios of 40% and 60% were used and crosshead speed was 10 mm min-1. Relaxation curves were normalized and the average regression coefficient of the fitted curves was 0.99. The slope of the fitted curve, which is related to the asymptotic residual force, was significantly lower in the outer zone than in the central zone at 60% of compression. The lowest values were at 27 days of ripening which outlined that ripened cheeses exhibited less solid properties than fresh cheeses in both outer and central zones. Rheological and physicochemical analysis allowed the characterization of cheese ripening.