Quantitative study of the relationships among proteolysis, lipid oxidation, structure and texture throughout the dry-cured ham process

Abstract

Temperature, salt and water contents are key processing factors in dry-cured ham production. They affect how proteolysis, lipid oxidation, structure and texture evolve, and thus determine the sensory properties and final quality of dry-cured ham. The aim of this study was to quantify the interrelationships and the time course of (i) proteolysis, (ii) lipid oxidation, (iii) five textural parameters: hardness, fragility, cohesiveness, springiness and adhesiveness and (iv) four structural parameters: fibre numbers, extracellular spaces, cross section area, and connective tissue area, during the dry-cured ham process. Applying multiple polynomial regression enabled us to build phenomenological models relating proteolysis, salt and water contents to certain textural and structural parameters investigated. A linear relationship between lipid oxidation and proteolysis was also established. All of these models and relationships, once combined with salt penetration, water migration and heat transfer models, can be used to dynamically simulate all of these phenomena throughout dry-cured ham manufacturing.

Manufacture of dry-cured ham: a review. Part 1. Biochemical changes during the technological process

“…Ruiz-Ramirez et al [16] showed that proteolysis index (degree of proteolysis) which is calculated as the percentage of nonprotein nitrogen divided by total nitrogen was 25 and 18 %, respectively, for Biceps femoris and Semimembranosus muscle (10 months of manufacturing). Similar results were obtained by Buscailhon et al, Flores et al and Harkouss et al [47][48][49].…”

“…Skrlep et al [80] also found for "Kraski prsut" dry-cured ham that a lower pH of the raw meat (from 5.51 to 5.63) had a positive effect on proteolysis compared to higher pH (from 5.80 to 6.18). This occurred due to the increased cathepsin activity at lower pH, which affects the extent of proteolysis [16,49,81,82]. Morales et al [77] also showed that proteolysis index decreased from 19.3 to 16.7 % when the salt concentration increased from 1 to 4 %.…”

“…Since proteins constitute as much as 80 % of the meat dry weight, the proteolytic reactions during manufacturing are important for the properties and the quality of dry-cured ham [49]. Muscle tissues contain a high number of various enzymes which contribute to the ripening process.…”

“…Between the stages from fresh meat to the final dry-cured ham, there is a loss of enzyme activity due to denaturation or degradation of the enzymes. The enzyme activity also decreases due to the decreasing water activity during the drying-ripening, as soon as water evaporates and the salt concentration increases [16,22,49,76,77].…”

“…The first step of the protein hydrolysis is caused by cathepsins B, L, H, and D, calpains, peptidases, and cytosolic enzymes, which degrade the muscle proteins to polypeptides [49,78,79].…”