Comparative Analysis of Quality of Raw Cut Steak in Different Parts

With the four different parts (plate tendon, sirloin beef the naked eye, and beef fillet) of raw cut steak as the research object, this paper made a comparative analysis of its conventional nutrients, volatile flavor substances, amino acids, the color L^* value, a^* value, b^* value, water retention, etc, investigated the differences of the different parts of the raw cut steak in nutrition characteristics, edible quality, and processing suitability. According to the results, among the conventional nutrients, the protein content of plate tendon was the highest, the fat content of sirloin beef was the highest, but with the lowest water content, while the fat content of beef fillet was the lowest but with the highest water content. A total of 100 kinds of volatile flavor substances had been detected in the four parts, and 50, 56, 48 and 40 kinds of volatile substances were detected in plate tendon, sirloin, naked eye and beef fillet, respectively. Among them, there were 9 kinds of volatile flavor substances shared by 4 parts of steak. Nonanal content ranked top in 4 parts of steak, which was one of the main flavor substances of raw cut steak. In the color difference, there were significant differences in L^*, a^* and b^* between beef fillet and the other three parts (P<0.05), with the lowest brightness and lighter color. The cooking loss rate of the four parts was small, without significant difference (P>0.05). Plate Tendon was suitable for cryopreservation because of its lowest thawing loss rate. Among the texture indexes, the hardness and chewiness of plate tendon were the highest, whereas the hardness and chewiness of naked eye were the lowest (P>0.05). The ratios of essential amino acid/total amino acid (EAA/TAA) to total amino acid (EAA/TAA) in 4 different parts of raw steak were 39.80%, 39.10%, 38.90% and 39.50%, respectively, which were all around 40%. The contents of glutamic acid, histidine and other umami amino acids in 4 different parts of raw cut steak were higher. Thus, the raw cut steak of four different parts belonged to high-quality protein.