Combined treatment of lactic acid-ultrasound-papain on yak meat and its tenderization mechanism

Abstract

The combined effects of lactic acid-ultrasound-papain on yak meat tenderization were investigated, and its tenderization mechanism elucidated. The optimal condition for combined tenderization was obtained with 0.03% lactic acid, ultrasound for 30 mins, and 200 U/g of papain. When compared with the untreated yak meat, the cutting force and the cooking loss of the tenderized yak meat were decreased by 62.16% and 31.25%, respectively, while the myofibrillar fragmentation index increasing 4.3 times. After the combined tenderization, it was observed a loose arrangement of muscle with larger gaps and cavities. The random-coil content of myofibrillar protein increased to 48.3%, while α-helix decreased to 14.4%, indicating that the myofibrillar protein underwent some unfolding and stretching. These results demonstrated that this combined treatment improved the tenderization of yak meat by disrupting muscle integrity, increasing its water-holding capacity, denaturing myofibrillar protein, and changing its spatial structure. The combined process using lactic acid-ultrasound-papain showed some potential to improve meat texture.