Effect of Meat Cooking on Physicochemical State and in Vitro Digestibility of Myofibrillar Proteins
Résumé
The effect of meat cooking was measured on myofibrillar proteins from bovine M. Rectus abdominis.
The heating treatment involved two temperatures (100 °C during 5, 15, 30, and 45 min and 270 °C
during 1 min). Protein oxidation induced by cooking was evaluated by the level of carbonyl and free
thiol groups. Structural modifications of proteins were assessed by the measurement of their surface
hydrophobicity and by their aggregation state. With the aim of evaluating the impact of heat treatment
on the digestive process, myofibrillar proteins were then exposed to proteases of the digestive tract
(pepsin, trypsin, and R-chymotrypsin) in conditions of pH and temperature that simulate stomach
and duodenal digestion. Meat cooking affected myofibrillar protein susceptibility to proteases, with
increased or decreased rates, depending on the nature of the protease and the time/temperature
parameters. Results showed a direct and quantitative relationship between protein carbonylation (p
< 0.01) and aggregation (p < 0.05) induced by cooking and proteolytic susceptibility to pepsin.
However, no such correlations have been observed with trypsin and R-chymotrypsin.