Seasonal Changes in Protein Composition of Whey from Commercial Manufacture of Caprine and Ovine Specialty Cheeses

Abstract

Pooled whey from the production of one variety of ovine cheese and two varieties of caprine cheeses was studied for gross composition and individual whey protein composition over one production season. Individual proteins were quantified by sodium dodecyl sulfate-PAGE and digital imaging technology. The mean proportion of α-lactalbumin (LA) from caprine wheys from the manufacture of Chevre and Cheddar-type cheeses was higher than values previously reported for bovine whey from Cheddar cheese; proportions of serum albumin, immunoglobulin (Ig)G, and β-lactoglobulin (LG) were lower. Ovine whey from Manchego-type cheese showed a higher proportion of β-LG, about the same proportion of α-LA, and lower proportions of serum albumin and IgG than did the bovine whey. Relative amounts of a-LA decreased throughout the season, but β-LG rose in midlactation and then gradually decreased toward the end of lactation. Relative proportions of serum albumin remained fairly stable throughout the year, and IgG decreased.