Effect of frozen storage on Port Salut Argentino cheese proteolysis. Analysis of the pH 4.6 water-soluble fraction

VERDINI, RA; ZORRILLA, SE; RUBIOLO, AC

Valparaíso, Chile

Congreso; IV Congreso Iberoamericano de Ingeniería de Alimentos; 2003

Instituto Chileno de Ingeniería para Alimentos y Universidad Técnica Federico Santa María

Port Salut Argentino is a soft cheese ripened at 5°C for approximately 30 days. Interest in expanding the commercialization of Port Salut Argentino cheese has led to the use of frozen storage as a preservation technique. However, frozen storage is thought to affect cheese structure and proteolysis and consequently, cheese flavor and texture. Casein hydrolysis into peptides and free amino acids is one of the more important changes that occur during cheese ripening. Therefore, the analysis of the evolution of peptides during ripening is useful to understand the effect of frozen storage on cheese proteolysis. The objective of this work was to determine the effect of frozen storage on the peptide profile that characterizes Port Salut Argentino cheese proteolysis. Chromatographic profiles of the pH 4.6 water-soluble fractions were monitored in control cheeses and in cheeses stored frozen at –22 °C for 30 days and then ripened at 5 °C considering different ripening times (1, 6, 13, 27, and 56 days) and at two sampling zones (central and external). Cheeses that underwent frozen storage revealed significant differences in the evolution of hydrophilic and low MW peptides but no significant differences in the evolution of hydrophobic and high MW peptides during cheese ripening. Some hydrophilic peptides were hydrolysed more rapidly from 6 to 13 ripening days in cheeses that underwent frozen storage, while other hydrophilic peptides, like fragment as1-CN (f1-23), were hydrolysed more rapidly from 13 to 56 ripening days. Therefore, frozen storage may be affecting the activity of bacterial proteases and peptidases, which are responsible of the hydrolysis of small peptides.