Candida Sp.99-125Lipase-catalyzed Synthesis Of Human Milk Fat Substitutes

Human milk is important to baby food that provide comprehensivenutrition for infant growth and development needing. At present,according to the study of the structural characteristics of human milksweet ester synthesis of human milk fat substitutes has become a hot spot.Preparation of human milk fat substitutes still exist many problems,such as: the expensive lipase catalyst,the complex enzymatic processtechnology,the higher costs of product separation. In this paper,thetechnology that three palmitic acid glyceride (PPP) and oleic acid (O) asraw material, Candida sp.99-125lipase as the catalyst for synthesis ofhuman milk fat substitutes (1,3-oleic acid2-Palm triglyceride OPO)was studied and optimized.The results showed that Candida sp.99-125can be used as biologicalcatalysts of human milk fat substitutes.The catalytic mechanism ofCandida sp.99-125lipase is that oleic acid have transesterification with Sn-1palmitic acid of PPP,then have transesterification with Sn-3palmiticacid of PPP.In this process,the Sn-2palmitic acid does not participate inthe reaction.After the optimization of reaction conditions,it was foundthat the best amount of lipase is25%of the quality of PPP,and the OPOconversion rate of41.24%after3h the reaction at the reactiontemperature was43℃.With the comparison of the character of Candida sp.99-125lipasebefore and after single batch reaction, the reuse of Candida sp.99-125lipase can be achieved by addition of the amount of lipase after a singlebatch reaction. The results showed that:by adding50%of the usage ofthe lipase used in the initial reaction, it was possible to keep the averageresponse rate being stable and the OPO conversion rate can bemaintained at around40%,after rejoin the substrate reaction48hours.It was found that the fed substrate PPP method can improve theconversion rate of the product OPO,by optimized the adding method ofsubstrate PPP.After reacting4h, the maximum response of the substratePPP was87.4%and the OPO conversion rate approached50.7%,byadding PPP4times and each time adding PPP as12.5%of the total massof oleic acid.