Study on the difference of muscle fiber types and quality in different parts of Xinjiang brown cattle

In order to study the type and quality of muscle fiber in different parts of Xinjiang brown cattle,muscle fiber and quality characteristics of beef cuts of Xinjiang brown cattle such as supraspinatus(SU),infraspinatus(IF),triceps brachii(TB),psoas major(PM),longissimus dorsi(LD),semitendinosus(ST),semimembranosus(SM)and biceps femoris(BF)were determined,and the correlation between beef quality and muscle fiber properties was studied by correlation analysis. The results showed that PM,LD and BF had the highest muscle fiber ratio of type Ⅰ,type ⅡA and type ⅡB fibers respectively. The diameter order was type ⅡB>ⅡA>Ⅰ. The diameters of the type Ⅰ,type ⅡA and type ⅡB fiber of PM were smaller than other parts. SU had lower b^* value,IF had lower WBSF,cooking loss. TB had higher WBSF,PM had lower Warner-Bratzler shear force(WBSF),hardness,gumminess,and pH value,and had higher cohesiveness and pressing loss. LD had lower chewiness,resilience and springiness. ST had lower pressing loss,cohesiveness and resilience,and had higher L^* value. SM had lower L^* value and chewiness,BF had higher springiness,cohesiveness and chewiness. Muscle fiber area and diameter of type Ⅰ,ⅡA and ⅡB fibers were positive correlated to WBSF,hardness and cooking loss(p<0.05). Muscle fiber area and diameter of type Ⅰ,ⅡA and ⅡB fibers were negative correlated to pressing loss(p<0.01).The muscle fiber ratio of type Ⅰ was negative correlated to hardness and WBSF(p<0.05). The muscle fiber ratio of type ⅡB was positive correlated to WBSF(p<0.05). The results showed that the muscle parts significantly affected the quality of beef,especially tenderness. Therefore,increasing the proportion of type I fiber,reducing the proportion of type ⅡB fiber would be beneficial to improve the beef tenderness.