Analysis of whey proteins during ripening of Afuega'l Pitu cheese by reversed phase HPLC

Evolution of the whey proteins fractions and proteolysis indices from 12 batches of the artisan cheese Afuega'l Pitu variety were studied by reversed phase high performance liquid chromatography (RP-HPLC) over the ripening period. The correlation coefficients between the whey protein contents and ripening time were very low, indicating that the whey protein content did not change as the cheese aged. However, soluble nitrogen content and the percentage of total nitrogen in the soluble form showed correlation coefficients higher than 0.9 with increasing ripening time. Analysis of variance showed significant differences (p < 0.05) between dairies for most of the variables with the exception of beta-lactoglobulin A and bovine serum albumin. These variables were also significantly different between the two manufacture zones. Conversely, no significant differences (p < 0.05) were observed between the two varieties of cheese, red and white, for whey protein content or for proteolysis indices.