Evolution of lean meat tenderness stimulated by coordinated variation of water status, protein structure and tissue histology during cooking of braised pork.

[Display omitted] • Shifts of α-helix to β-sheet decreased the water-holding capacity of lean meat. • The occurrence of heat-induced protein oxidation toughened the lean meat. • Immobilized water was responsible for the softness of lean meat. • The rupture of perimysium structure enhanced the tenderness of lean meat. Tenderness of lean meat in braised pork is of great importance to the consumer palatability and acceptance. The influence of water status, protein structure and histological changes on lean meat tenderness during cooking was investigated. Results indicated that lean meat began to tenderize mainly after 20 min-cooking. In the early period of cooking, the decrease of total sulfhydryl content caused the protein oxidative cross-linking, leading to the gradual unfolding of the protein structure, thus resulting in a decrease of T 22 and an increase of centrifugal loss, which decreased the tenderness of lean meat. However, after cooking for 20 min, the β-sheet decreased and random coil increased, thus generating conversion between P 21 and P 22. The rupture of perimysium structure was observed. Changes in protein structure, water status, and tissue histology could facilitate the initiation and development of lean meat tenderness. [ABSTRACT FROM AUTHOR]