In vitro protein digestibility of pork products is affected by the method of processing.

Processing contributes to different flavors and textures of pork products. However, processing methods have also showed a great impact on meat nutrition. In this study, protein digestibility and digested products were compared among four kinds of processed pork products (cooked pork, emulsion-type sausage, dry-cured pork and stewed pork). Cooked samples were homogenized and digested by pepsin and trypsin. The digestibility of meat proteins was evaluated by particle size measurement, SDS-PAGE, and LC-MS/MS. Emulsion-type sausage had the highest digestibility and the lowest particle size (P<0.05), while stewed pork showed the opposite results (P<0.05). Band profiling on SDS-PAGE gels were significantly different before and after digestion, and between pork products as well. LC-MS/MS analysis revealed that stewed pork samples had the greatest number of 750-3500Da Mw peptides in digested products, while emulsion-type sausage had the smallest number of peptides between 750 and 3500Da. Long-time salting and drying, and long-time and high-temperature cooking may induce pork proteins to being less susceptible to pepsin digestion.