The Exploitation Of A Novel Long-Chain Low-Calorie Functional Lipids

A new kind of low-calorie structured lipid, very long-chain triacylglycerols, was interesterified with glycerol and rice bran wax (RBW) using Novozyme435as biocatalyst. First, the fatty acids of RBW were analyzed by GC-MS. The result shows that RBW was mainly composed of C14～C30fatty acids, including95%even carbon number fatty acids, among which C22and C24fatty acids were the major ones (72.59%). RBW also contains unsaturated fatty acid, oleic acid.The effects of reaction temperature, reaction time, enzyme dosage, substrate molar ratio on the content of structured lipids were explored in this study. Response surface methodology (RSM) was used to optimize the reaction conditions. Thin layer chromatography (TLC) was used for qualitative and quantitative analysis of newly synthesized lipids and column chromatography was used to separate and purify the glyceride. The melting characteristics and fatty acid species of purified glyceride were anlyzed by differential scanning calorimetry (DSC) and GC-MS, respectively.The highest content of SL-TAG was obtained when glycerol and RBW at a ratio of2:1reacted at65℃for36h with an enzyme amount of5.62%. Under the best conditions, the actual content of SL-TAG was up to79.80%, very close to the predicted value. The newly synthesized SL-TAG showed melting point range of30～68.8℃. It contained C14, C16, C18:1, C18, C20, C21, C22, C23, C24, C26fatty acids, with C16being the predominant one (26.62%). C22ranked second with contents of22.51%. The optimal conditions for SL-DAG were as follows:reaction temperature was60℃, the substrate molar ratio of glycerol and RBW was3:1,enzyme amount was4.08%, reaction time was22.42h. The content of SL-DAG was44.09%under the best conditions. It contained C16, C18:1, C18, C20, C22, C23, C25, C26fatty acids with C22being the major one (52.89%) and its melting point range was41～79.8℃. The maximum amount of SL-MAG was55.49%and it was achieved when glycerol and RBW at a ratio of6.68:1reacted for6h at60℃with an enzyme amount of8.23%. The SL-MAG, whose melting point range was32～76.6℃, contained C14, C16, C18:1, C18, C20, C21, C22, C23, C25, C26, C28, C30fatty acids, the content of C22was the largest (53.25%).