Marinating beefsteak with soy sauce and broccoli (Brassica oleracea var. italica) juice and its effects on physicochemical and qualitative characteristics of meat during aging

Protease activity of various fruits and vegetables has been studied by previous researchers. Broccoli is one of the most abundant and affordable vegetables which is intrested by consumers and researchers due to its pleasant flavor and nutritional attributes e.g. anticancer and antioxidant compounds, such as sulforaphane, indole-3-carbinol and selenium. This study was conducted to investigate the effect of broccoli juice and soy sauce on physicochemical and textural characteristics of beefsteak with the aim of tenderizating and reducing aging time.

Meat samples were separated from the beef (Round Steak) muscle. The steak samples were cut into cubic pieces (10 cm3) with a weight of approximately 1 kg and free of fat. The marinade composition consisted of 2.6% (W/V) broccoli juice (Protease activity: 12.3 u/g) and 25% (W/V) soy sauce were prepared in three treatments compared to control and were injected into the superficial and deep segments. The samples were analysed at 1, 3, 24 and 48 hours storage in refrigerator (4 ° C ).

According to the results of analysis of variance, the tenderization parameters of all treatments were significantly higher than control (p<0.05). The value of tender parameters composed of myofibrillar fragmentation index, myofibrillar protein solubility, insoluble collagen and shear force were better in treatment containing broccoli + soy sauce than others. Also, scanning electron microscopy results of the treatment containing broccoli juice + soy sauce confirmed this finding. The highest and lowest mean value of drip loss were observed in soy sauce (1.97%) and broccoli juice (1.72%), respectively. In the present study, the rate of cooking loss decreased from 1 h to 48 h in all treatments. During tenderization period, the shear fore mean value of all treatments showed a significant decrease due to enzymatic activity and the progress of the meat aging process. The minimum shear force mean value were recorded in broccoli + soy sauce (128.5N), broccoli juice (151.1N), soy sauce (166.8N) and control (187.5N) respectively during cold storage. Based on our findings, the combination of broccoli juice and soy sauce can be used as an effective marinade in improving beefsteak tenderness.

The result of this study showed that, broccoli juice may have proteolytic components that are effective in myofibrillar proteins degredation. The proteolytic activity of these enzymes was higher at low pH. Therefore, the higher myofibrillar proteins degredation as well as their solubility were obtained in treatment containing broccoli + soy sauce.