Triglyceride specificity of<i>Candida cylindracea</i> lipase: Effect of docosahexaenoic acid on resistance of triglyceride to lipase

Abstract

Abstract Tuna oil was hydrolyzed with Candida cylindracea lipase. After 70% hydrolysis of the oil, the docosahexaenoic acid (DHA) content in the glyceride mixture [a mixture of TG (triglyceride), DG (diglyceride) and MG (monoglyceride)] was twice that of the original oil. DHA‐rich TG and DG were observed, but DHA‐rich MG was absent. C. cylin‐dracea lipase seemed to have a “triglyceride specificity,” and it favors TG without DHA over TG containing DHA. In accordance with this hypothesis, TG containing a mixture of oleic acid (OA) and DHA was synthesized and then hydrolyzed with C. cylindracea lipase. TGs in the hydrolysis product were fractionated and analyzed quantitatively by high‐performance liquid chromatography. Four kinds of TGs were obtained. TG with three molecules of OA was hydrolyzed most easily. Increasing the DHA content of TG resulted in less hydrolysis of TG. The results suggested that C. cylindracea lipase had a TG specificity for the whole structure of TG in preference to the individual ester bonds; OA coexisting with DHA in TG was resistant to C. cylindracea lipase due to the TG structure.