Release of Volatile Branched-Chain and Other Fatty Acids from Ruminant Milk Fats by Various Lipases

Abstract

Bovine, ovine, and caprine milk fats were treated with pregastric lipases (kid goat, calf, and lamb), microbial lipases (Candida cylindracea, C. cylindracea AY30, Aspergillus niger APF12, Rhizopus arrhizus, Penicillium roqueforti R10, and Mucor zavanicus Map 10), porcine pancreatic lipase, or milk lipase. All three pregastric lipases preferentially hydrolyzed volatile branched-chain and short n-chain fatty acids from each milk fat. Pregastric lipases also released a relatively low proportion of C₁₀ from bovine milk fats but a high proportion of C₁₀ from caprine milk fat. Milk lipase released very low concentrations of butanoic acid and did not release 4-methyloctanoic acid in significant amounts except from caprine milk fat. Ovine milk fat yielded a substantially greater concentration of butanoic acid than did bovine or caprine milk fats when it was hydrolyzed by porcine pancreatic lipase. Candida cylindracea lipase yielded high amounts of volatile n-chain fatty acids nonselectively and only small quantities of volatile branched-chain fatty acids. High amounts of the medium-chain branched fatty acids were produced by kid goat, P. roqueforti, A. niger, and R. arrhizus lipases.