PA milk cheese showed a more important hydrolysis (P-0.05) of as1-casein than RA milk cheese at the first stages of ripening
(15 days), while PR milk cheese had a level between those seen in PA and RA milk cheeses. Degradation of b-casein was more
important (P-0.05) in PA and PR than in RA milk cheeses at 15 days of ripening. However, from thereon b-casein in PR and
RA milk cheeses was hydrolyzed at essentially similar rates, but at lower rates (P-0.05) than in PA milk cheeses. Pressure
treatment could induce proteolysis of b-casein in a way, which is different from that produced by heat treatment. There was an
increase in 4.6-soluble nitrogen (WSN) and in trichloroacetic acid (TCASN) throughout ripening in cheeses, but higher contents
(P-0.05) in PA and PR milk cheeses at the end of ripening were observed. PR milk cheeses contained considerably higher
content (P-0.05) of free amino acids than RA or PA milk cheeses. In general, heat and pressure treatments had no significant
effect on the levels of hydrophobic and hydrophilic peptides.
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