Lipid composition of the intramuscular fat of beef from Spanish cattle breeds stored under modified atmosphere.

The lipid composition of intramuscular fat from 30 young bulls of 5 Spanish cattle breeds (Asturiana de los Valles, Morucha, Parda Alpina, Pirenaica and Retinta) was studied. Steaks from each shortloin were packaged in 60% O(2), 30% CO(2) and 10% N(2) and aged for 0, 5, 10 and 15 days. Lipid classes obtained by thin layer chromatography and total fatty acids obtained by gas chromatography were evaluated. Meat from Asturiana de los Valles had high PL and C contents, and low TG contents that reflected its low intramuscular percentage content. This breed showed high FFA content that likely originated from lipolysis of PL. The main breed effect was due to the low intramuscular fat content observed in the Asturiana de los Valles. After 5 days, FFA decreased because they were probably transformed into other compounds. The Morucha breed may have a genetic predisposition for depositing MUFA, and the high MUFA and C14:0 values observed in the Morucha breed were likely due to its high intramuscular fat percentage. Regarding fatty acid composition, no "days of storage" effect was observed for any of the studied fatty acids, except for C18:3ω6 that increased during the first 5 days of storage in Asturiana de los Valles. Concerning the fatty acid composition, Asturiana de los Valles had the highest PUFA/SFA ratio, while Parda Alpina and Morucha possessed low ω6/ω3 ratios but high C22:6ω3 contents. Finally, the presence of C22:6ω3 and 15-CH(3)-C16:0 may be related to higher intramuscular fat contents.