辛酸结构大豆磷脂酶法改性工艺优化Process optimization of enzymatic modification of octanoic acid-structured soybean phospholipids

Abstract

为了改善天然磷脂的理化性质以及拓宽其应用范围，以辛酸和大豆磷脂为底物，采用酶法对大豆磷脂进行改性。筛选了改性大豆磷脂的脂肪酶，考察了反应温度、反应时间、脂肪酶用量、底物质量比对辛酸结构大豆磷脂改性工艺的影响，在此基础上，采用正交试验优化大豆磷脂的酶法改性工艺条件，并考察了脂肪酶的重复利用性。结果表明：Novozym 435脂肪酶的催化效果优于Lipozyme RM IM和Lipozyme TL IM；大豆磷脂酶法改性的最优条件为反应温度55 ℃、Novozym 435用量25%、底物质量比（辛酸与大豆磷脂质量比）7∶ 1、反应时间36 h，在此条件下辛酸结合率可达（78.79±0.81）%；Novozym 435经过4次重复利用后，辛酸结合率仍能达到（63.67±150）%。综上，Novozym 435可作为催化磷脂改性的优选脂肪酶。In order to improve the physicochemical properties of natural phospholipids as well as to expand their applications, soybean phospholipids were modified by an enzymatic method using octanoic acid and soybean phospholipids as substrates. Lipases for modifying soybean phospholipids were screened, and the effects of reaction temperature, reaction time, lipase dosage and substrate mass ratio on the modification process of octanoic acid-structured soybean phospholipids were investigated. On this basis, orthogonal tests were used to optimize the process conditions of the enzyme-catalyzed modification of soybean phospholipids, and the reusability of the lipases was determined. The results showed that the catalytic effect of Novozym 435 was stronger than that of Lipozyme RM IM and Lipozyme TL IM. The optimal conditions for the enzyme-catalyzed modification of soybean phospholipids were reaction temperature 55 ℃, Novozym 435 dosage 25%, mass ratio of octanoic acid to soybean phospholipids 7∶ 1, and reaction time 36 h. The octanoic acid binding rate was (78.79±0.81)% under the optimal conditions, and the octanoic acid binding rate still reached (63.67±1.50)% after four times of reuse of Novozym 435. In conclusion, Novozym 435 can be used as a preferred lipase to catalyze the modification of phospholipids.

Keywords

• 大豆磷脂；脂肪酶；脂肪酸；酶法改性；结构磷脂
• soybean phospholipids; lipase; fatty acid; enzymatic modification; structured phospholipids