Effect of Traditional and Dry Package Ageing on Physicochemical Properties and Protein Digestibility of Pork Longissimus Thoracis Muscle

The aim of the study was to evaluate the effect of traditional (unpacked) and dry package ageing on quality characteristics, proteolysis and protein digestibility of pork loins aged for 28 days. Changes in pH and weight loss as a function of ageing were more pronounced in traditionally aged loin in comparison to that aged in a bag. Both traditional and bag ageing induced the enzymatic protein degradation process. However, higher amounts of protein degradation products were observed for in bag aged samples compared to traditionally aged samples. The effect of ageing on protein digestibility was evaluated using a simulated in vitro oral-gastrointestinal digestion model. A significant (P < 0.05) impact of ageing was observed and the protein digestibility of the samples showed an increasing trend with ageing time. This was reflected in the results of peptide concentration and free amino acids which showed a significantly increasing trend (P < 0.05) with increased ageing time. A higher degree of protein hydrolysis and higher concentration of peptides were observed for most of the in bag aged samples compared to traditionally aged samples. These results indicate the superiority of in bag ageing in terms of protein digestibility.