Study On Enzymatic Synthesis Of Polyglycerol Fatty Acid Ester And Its Function

Polyglycerol fatty acid ester is a new type of emulsifier,which has been studied in recent years due to its great advantages,such as natural source,high safety,wide HLB range and good emulsifying stability,thus widely used in food,cosmetic,pharmaceutical and other industries.In this study,the physical and chemical properties of polyglycerol fatty acid esters were studied by using the fatty acids of different chain lengths.The application of the polyglycerol fatty acid esters in emulsion and drug delivery system was also discussed by using monoglyceride as positive control.The results are as follows:Firstly,in this study,sodium hydroxide was used to catalyze the dehydration of glycerol under high temperature.Single factor test and the orthogonal experiment were used to optimize the synthesis of polyglycerol,and the light brown polyglycerol product with a degree of polymerization of 3.61 and non-irritating odor was obtained under the optimum conditions.After the purification of the molecular distillation equipment,the purity of the final polyglycerol product can reach 86.33%,which is consist of 68.30% diglycerin,13.13% trimethylene glycerol,3.18% tetraglycerol.Secondly,immobilized lipozyme 435 was used to catalyze the synthesis of different chain fatty acid polyglycerides from rice bran oil,camphor seed oil and acetic acid in solvent-free system.Single factor test and the orthogonal experiment were used to optimize the synthesis process.Under the optimum reaction conditions,the average esterification rate of three raw materials was 69.37%,67.34% and 71.68% respectively,and the components of the polyglyceride product were identified by FTIR and HPLC / ESI / MS.Then,the self-made polyglycerol HLB values were calculated greater than 7 by Griffin proposed method,which identified as hydrophilic emulsifier.The emulsifying performance and foaming properties of self-made polyglyceride products were studied using the most widely used emulsifier monoglyceride as comparision.The results showed that the minimum additions of emulsifier in the stability,centrifugal stability and heat stability of the long carbon chain fatty acid polyglycerol ester emulsion were 0.1%,0.1% and 0.3% respectively,and the minimum additions of the medium carbon chain fatty acid polyglycerol ester emulsion were 0.3%,0.3%,0.3%.The short carbon chain fatty acid polyglyceryl ester and monoglyceride emulsion quite unstable,prone to oil droplets coalescence and oil-water separation phenomenon.When the amount of emulsifier was increased to 0.3%,the emulsion prepared from the polyglyceride synthesized by rice bran oil was the most stable and the particle size was only 16.8nm.The foaming and foaming stability of the emulsions prepared by the polyglycerides synthesized from camphor seed oil were the best,reaching 76.34% and 92.96% respectively.In the end,the curcumin was used as the research object,and the curcumin emulsion embedding system was prepared by the method of precursor injection.The effects of the amount of raw materials,the amount of stabilizer and the amount of curcumin on the entrapment efficiency of emulsion embedding system were investigated by single factor test.The results showed that the best additions of the above three factors were 20%,0.1g,7%,respectively.Under these conditions,the emulsion embedding system encapsulation efficiency of long,medium and short chain fatty acid polyglycerides and monoglycerides to 51.31%,43.01%,5.12%,58.96%,respectively.