Influence of the processing conditions of Iberian ham on proteolysis during ripening

Non-protein nitrogen and its fractions (peptides, amino acids and volatile basic nitrogen) were determined in biceps femoris and semimembranosus muscles of two homogeneous groups of Iberian dry-cured ham in different stages of maturation, and ripened in two different factories under different environmental conditions. A progressive increase in non-protein nitrogen was observed during ripening in all groups, being especially intense during the drying stage, when the temperature was the highest during maturation. During the first stages of processing, the proportion of peptides and free amino acids remained similar while free amino acids increased more markedly from the drying stage, representing the largest fraction at the end of the process. Volatile basic nitrogen was the least abundant fraction of non-protein nitrogen during ripening. Hams kept at higher temperature during longer periods, and with lower salt content, produced larger amounts of all three fractions of non-protein nitrogen in fully ripened dry-cured Iberian ham.