Effect of proteolysis index on texture of dry-cured ham.

Abstract

The objective of this study was to determine the effect of proteolysis index on the relationship between water content and hardness in the interior of dry-cured hams. To obtain different degrees of proteolysis 18 hams from two pH groups (high: of 6.2 until 6.8 and low: of 5.5 until 5.7) and three added NaCl levels (2, 5 and 8%) were used. The pH was measured in semimembranosus muscle at 24 h postmortem (pHSM24). The biceps femoris muscle was excised from dry-cured hams at the end of the process. Thereafter nine samples were shaped into parallelepipeds of 4×2×2 cm and dried to different levels of moisture content covering the range from 30.6 to 58.2%. The rest of the muscle was ground and vacuum packed until its subsequent physicochemical analysis. At the end of drying period, a Texture Profile analysis was carried out to determine textural parameters of the samples. The hardness of biceps femoris muscle of dry-cured hams diminished when the IP was increased. The cohesiveness diminished with the proteolysis index, the differences in cohesiveness by effect of proteolysis index were more important at high moisture contents similar to those existing inside of dry-cured ham during the ageing. The reduction of added NaCl level in the production of dry-cured ham, especially in hams with low pHSM24, causes a higher proteolysis index in the final product. Dry-cured hams samples with higher proteolysis index present lower hardness and higher cohesiveness, and could produce an unwanted pasty and / or soft texture (In Spanish).