Characterization of beef semimembranosus and adductor muscles from US and Mexican origin.

The purpose of this study was to compare the chemical composition and sensory characteristics of two beef muscles (semimembranosus, SM and adductor, AD) from the inside round of Mexican and US origins. Inside rounds were obtained from 20 Mexican bull carcasses, representing beef of Mexican origin. Forty-vacuum packaged USDA Choice and Select inside rounds were purchased from a local trader, representing US beef. Muscles were analyzed for chemical composition, Warner-Bratzler shear force (WBSF), cooking loss percentage, instrumental color, textural profile, and consumer acceptability. Muscles imported from the US contained more intramuscular fat, had higher cooking loss percentages, lower shear force values, and higher consumer ratings for overall desirability than Mexican counterparts (P<0.05). Choice and Select beef samples had similar WBSF values (P>0.05). Consumers found differences in juiciness and tenderness ratings between the two muscles, with the SM being tougher and less juicy than the AD (P<0.05).