Slip point of subcutaneous adipose tissue as an indicator of beef carcass quality
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We hypothesized that slip point of subcutaneous (s.c.) adipose tissue lipids would predict beef carcass quality. To address our hypothesis, 79 M. longissimus dorsi (LD) steaks from cattle of unknown background were used to provide information on slip points, percentage intramuscular lipid, fatty acid composition, and MUFA:SFA ratios. Overlying s.c. adipose tissue was separated from the muscle lean, which contained intramuscular (i.m.) adipose tissue. Lipids were extracted from s.c. adipose tissue and muscle lean by a modified chloroform:methanol procedure and subjected to various analyses. The hypothesis was tested by developing regression equations to determine which fatty acid variables were most useful in predicting carcass composition. There was a high correlation between s.c. MUFA:SFA ratio and s.c. slip points (P < 0.001) with an R2 of 0.557. Also, the MUFA:SFA fatty acid ratios of s.c. and i.m. adipose tissue were significantly correlated and an R2 of 0.440 was observed (P < 0.001) when regressed against each other. The current data set observed s.c. MUFA:SFA ratios (0.73) lower than previous studies, which suggests a population of young or unfinished cattle. This study demonstrated that it is possible to predict the intramuscular lipid (IML) MUFA:SFA ratio by measuring s.c. slip point (R2 of 0.097; P < 0.01). However, our hypothesis of predicting amount of marbling, hence quality grade, from the melting temperature of s.c. adipose tissue lipids proved incorrect (R2 = 0.001). Nonetheless, these data indicate that LD fatty acid composition can be estimated by measuring s.c. adipose tissue slip point.
Ward, Lindsay Paige (2008). Slip point of subcutaneous adipose tissue as an indicator of beef carcass quality. Master's thesis, Texas A&M University. Available electronically from