酶法改性樟树籽仁油制备含ω-3多不饱和脂肪酸结构脂质及其理化性质与抗氧化活性

Preparation of structured lipid containingω-3 polyunsaturated fatty acids by enzymatic modification of Cinnamomum camphora seed kernel oil and its physicochemical properties and antioxidant activity

采用固定化脂肪酶Novozyme 435催化鱼油乙酯和樟树籽仁油(CCSKO)酯交换制备含ω-3多不饱和脂肪酸结构脂质。通过单因素试验对制备工艺条件进行优化,得到的最佳反应条件为:底物摩尔比1∶1,反应温度60℃,反应时间8 h,酶载量10%(以底物质量计)。在最佳反应条件下,含EPA/DHA结构脂质的含量为(24.34±0.33)%,且酶重复稳定性较好。放大制备试验后,采用150℃短程分子蒸馏纯化,产物中结构脂质含量达到(44.22±0.57)%,中碳链脂肪酸、长碳链脂肪酸含量比例约为3∶1,EPA含量为(11.91±0.44)%,DHA含量为(7.67±1.11)%。结构脂质的甘油三酯组成主要为CC-EPA((11.07±0.11)%)、CC-DHA((6.71±0.21)%)、CLa-EPA((7.78±0.51)%)和CLa-DHA((5.99±0.25)%)。制备的结构脂质的酸价(KOH)为(0.39±0.08)mg/g,皂化值(KOH)为(250.31±1.02)mg/g,碘值(I)为(54.87±0.86)g/100 g,过氧化值为(1.12±0.01)mmol/kg,均符合食用油脂制品国家标准。结构脂质清除DPPH自由基及ABTS自由基的IC50值分别为(13.92±0.18)mg/mL及(8.99±0.05)mg/mL,表明其具有较强的抗氧化能力。

Preparation of a new structured lipid(SL)containingω-3 polyunsaturated fatty acids through immobilized lipase Novozyme 435-catalyzed transesterification of Cinnamomum camphora seed kernel oil(CCSKO)and fish oil ethyl esters was investigated.The transesterification conditions were optimized using single factor experiment as follows:molar ratio of CCSKO to fish oil ethyl esters 1∶1,enzyme amount 10%(based on the mass of total substrates),reaction temperature 60℃and reaction time 8 h.Under the optimal reaction conditions,the content of SL containing EPA or DHA was(24.34±0.33)%,and the enzyme maintained good stability.After a scale-up trial,the crude product was purified by a short path molecular distillation at 150℃and the purity of SL was(44.22±0.57)%,the ratio of medium carbon chain fatty acids(MCFA)to long carbon chain fatty acids(LCFA)was 3∶1,and the contents of EPA and DHA were(11.91±0.44)%and(7.67±1.11)%,respectively.The triglyceride compositions of SL were mainly CC-EPA((11.07±0.11)%),CC-DHA((6.71±0.21)%),CLa-EPA((7.78±0.51)%)and CLa-DHA((5.99±0.25)%).The acid value,saponification value,iodine value and peroxide value of SL were(0.39±0.08)mgKOH/g,(250.31±1.02)mgKOH/g,(54.87±0.86)gI/100 g and(1.12±0.01)mmol/kg,which met the national standards for edible oil product.The IC50 values of SL for scavenging DPPH free radical and ABTS free radical were(13.92±0.18)mg/mL and(8.99±0.05)mg/mL,respectively,indicating that SL had good antioxidant capacity.