| The medium-long carbon chain structure lipid has attracted the attention of many researchers at home and abroad in recent years because it can provide essential fatty acids and quickly function as an organism.In this paper,natural eucalyptus seed oil rich in medium-chain fatty acids was used as raw material,and the structural lipids rich in linoleic acid and linolenic acid were synthesized by immobilized lipase-catalyzed transesterification technology and suitable conditions.The research contents and results are as follows:1.Screen out the best immobilized lipase Lipozyme TL IM,and use the single factor experiment to target the STG yield as the index,the four factors affecting the transesterification efficiency(substrate molar ratio(Cinnamomum camphora seed kernel oil: Soybean oil: linseed oil),enzyme amount(percentage of substrate),reaction time,and reaction temperature were determined.On the basis of single factor experiment,the response factor method was used to optimize the four influencing factors to achieve the maximum lipase-catalyzed transesterification efficiency.The optimal transesterification conditions were as follows: the substrate molar ratio was(Cinnamomum camphora seed kernel oil: soybean oil + Flaxseed oil)1.6:1(where soybean oil: linseed oil = 1:1),the amount of enzyme added is 6.3%,the reaction time is 3.7h,the reaction temperature is 46 ° C,and it is repeated under the optimal experimental conditions.A sub-verified parallel experiment yielded an average yield of the target product STG of 50.06 ± 0.57%.The repeated stability experiments of lipase were carried out under the optimal experimental conditions.The results showed that Lipozyme TL IM maintained high catalytic efficiency after repeated 10 times,which provided a basis for its industrial application.2.After the secondary molecular distillation technique,the free fatty acids in the transesterification products and the non-target products of ECN<34 and ECN=34 were substantially removed,and the yield of structural lipids was increased to 63.41%.The triglyceride configuration and content are CLC/CLnLn/CLnLa(6.07%),COC/CPC(3.33%),LaLnLa/CLnL(23.87%),LnLnLn(0.59%),CLL(2.21%),LaLLa/LaLnL(18.65%),LaLnO/LaLM(8.69%).The fatty acid composition of eucalyptus seed oil and purified structural lipid was compared.The results showed that the saturated fatty acid content of structural lipid was 37.21±0.85%,the unsaturated fatty acid content was 62.79±0.21%,and the medium carbon chain fatty acid content was 29.55±0.14.%,long carbon chain fatty acid content is 70.45 ± 0.34%,and the structural lipid s glycerol skeleton sn-2 is mainly composed of oleic acid(14.54 ± 0.53%),linoleic acid(32.31 ± 0.87%),linolenic acid(24.55 ± 0.93%)composition,while sn-1,3 position of tannic acid(23.43 ± 0.36%),lauric acid(21.42 ± 0.42%)content is higher.Studies have shown that the long carbon chain fatty acids at the sn-2 position of the triglyceride glycerol skeleton can be rapidly digested and absorbed in the body,so retaining linolenic acid and linoleic acid at the sn-2 position is good for health,and sn-1,3 The medium carbon chain fatty acids provide fast energy and reduce fat accumulation in the body.3.The physical and chemical properties of structural lipids were tested by relevant national standards.The results showed that they all met the national national standards for edible vegetable oil safety(GB 19641-2015).The solid fat content of the structural lipid was examined,and the results showed that the solid fat content of the structural lipid was significantly reduced relative to the eucalyptus seed oil and the content was substantially zero.The melting crystallization characteristics of structural lipids showed that the peak melting peak and peak crystallization peak of the structural lipids of eucalyptus seed oil decreased,and were significantly lower than human body temperature(37?). |
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