Ham processing: effects of tumbling, cooking and high pressure on proteins

Meat is recognized as an important source of protein and amino acids. Before consumption, meat products are transformed, and processing modifies the protein characteristics and impacts their digestibility. The present study aims to evaluate the impact of physicochemical modifications (solubility, oxidation, and denaturation) on the degree of in vitro digestibility and the digestion rate of high-pressure-treated cooked ham during the different process steps (curing, cooking and high-pressure treatment). Samples were homogenized and digested by pepsin and then by trypsin. The curing step increased the degree of proteolysis and the digestion rate compared with those of raw meat. Brining and tumbling caused partial denaturation of the proteins, which provided digestive enzymes better access to their specific cleavage sites. Otherwise, the substantial denaturation and protein oxidation induced by the cooking step decreased the degree of digestibility and significantly increased the digestion rate of cooked ham. Finally, the high-pressure treatment decreased the digestibility of cooked ham and simultaneously increased its digestion rate. The denaturation and oxidation phenomena leading to protein aggregation thus masked the cleavage sites necessary for the digestive enzymes. Therefore, each step of the processing of high-pressure cooked ham had an impact on the protein digestion parameters: the curing step promoted the digestibility and proteolysis rate of pork protein, while cooking and high-pressure treatment reduced the digestibility and proteolysis rate of pork protein.