L-Arginine and L-lysine can weaken the intermolecular interactions of main myofibrillar proteins: the roles in improving the tenderness of pork Longissimus lumborum muscle

This work aims at investigating the mechanisms underlying the effects of L-arginine and L-lysine on the ten-derness of pork Longissimus lumborum muscle. The results indicated that on day 7, L-arginine and L-lysine were able to decrease the shear force from 71.47 to 27.59 or 32.53 N, but raise the myofibrillar fragmentation index from 70.93 to 88.2 or 92.4, compared to the control. Additionally, L-arginine inhibited the degradation of desmin, troponin-T and titin; while L-lysine inhibited the degradation of desmin, troponin-T, titin and nebulin. (L)-Arginine, especially (L)-lysine alleviated the Z-disc damage, while accelerated the M-line dam-age. (L)-Arginine and L-lysine promoted the extraction of myosin, titin and some unidentified proteins, decreased ionic bonds but increased hydrophobic interactions. The results suggest that the weakening of the intermolecular interactions between main myofibrillar proteins by (L)-arginine or (L)-lysine may play crucial roles in improving meat tenderness. The finding may broaden the way to tenderise meat.