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

•Processing methods affect protein bioavailability of pork products.•High-temperature and long-time cooked stewed pork were less digested by pepsin.•Particle size could be associated with susceptibility to digestive enzyme and digestibility.

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- 3500 Da Mw peptides in digested products, while emulsion-type sausage had the smallest number of peptides between 750 and 3500 Da. Long-time salting and drying, and long-time and high-temperature cooking may induce pork proteins to being less susceptible to pepsin digestion.

Graphical abstractDownload high-res image (67KB)Download full-size image