Evaluation of green kiwifruit juice extract on physicochemical properties, antioxidant activity, and tenderness of beef M. semitendinosus with in vitro digestion.

This study focused on the physicochemical properties and tenderness of vacuum-packaged beef M. semitendinosus as affected by various dilution ratios (DRs, 1:4, 1:2, and 1:1) of green kiwifruit juice extract (GKJE) with phosphate buffer during storage at 4°C for 7 days. In addition, the formation of peptides with antioxidant activity for GKJE ability to hydrolyze proteins present in beef was evaluated at different steps of in vitro digestion. Beef with GKJE showed higher tenderness than control (CTL, beef with brine solution alone) during storage, and the increased DR increased tenderness as compared to lower DRs. The addition of GKJE increased protein digestibility during in vitro digestion. To increase the antioxidant activity in the body, GKJE having a DR of 1:2 and 1:1 should be applied to the beef muscle with effective antioxidant activity. These results suggest that DRs of phosphate buffer and kiwifruit juice of 1:1 and 1:2 have the potential to be used as a meat-tenderizing agent and could increase the digestibility of meat as well as the antioxidant capability of bioactive peptides. PRACTICAL APPLICATION: The dilution ratio of kiwi juice with phosphate buffer at 1:1 has the potential to be used as a meat-tenderizing agent during refrigerated storage and also increase the digestibility of beef.