Preparation Of Erythritol Ester And Study On Its Oil Gel Properties

Structured vegetable oil and its application technology have become one of the research hot spots in recent years.The formed structured vegetable oil gel can fundamentally reduce the content of trans fat and saturated fat in food,with strength and plasticity like solid fat,and become a healthy fat that can replace the traditional application of solid fat.The study of new gel factors has become an important part in the study of structured vegetable oil.In this study,erythritol and octanoic acid were used as raw materials to synthesize a new fatty acid sugar ester-erythritol dioctanoate and its gel properties were studied.The physical and chemical properties,microstructure and gel mechanism of the structured vegetable oil gel and emulsion gel were analyzed and characterized.The main contents are as follows:(1)Preparation,purification,identification and process parameter optimization of erythritol dioctanoate.First,select the preparation parameters,and determine that sodium bisulfate monohydrate is the most suitable catalyst,and cyclohexane is the best water-carrying agent.Solvent extraction and silica gel column chromatography were used to separate and purify the products.And by HPLC,FT-IR,NMR detection and analysis showed that the isolated and purified product is erythritol dioctanoate.Through single factor and response surface method to optimize the process parameters,the best conditions are obtained: reaction temperature 92.46 ?,acid-alcohol molar ratio 3.06:1,catalyst amount 11.06%,reaction time 21.6 h,under this condition the product yield can reach 90.8753%.(2)Performance analysis of structured vegetable oil gel prepared from erythritol dioctanoate.Soybean oil,sunflower seed oil,linseed oil and camellia oil were selected to prepare gel oil.The gel properties of erythritol dioctanoate were measured from the aspects of minimum gel concentration,complete gel time and oil holding.The microstructure of the gel oil was analyzed by polarized light microscope,XRD and FTIR,so as to explore the influence of the microstructure on the macroscopic properties,such as structural properties,rheological properties and oxidation stability.The results showed that the minimum gel concentration of erythritol dioctanoate was stable at 4-5%.The complete gelation time was related to the type of vegetable oil and gel concentration.The gel concentration was positively correlated with the gel oil holding rate.Erythritol dioctanoate forms acicular crystals in the gel oil and appears polycrystalline type,in which there is a six square crystal system of subcrystalline cell structure.FTIR detected that the main force to maintain the gel structure was not hydrogen bond.The gel system constructed by this microstructure improves the hardness and viscosity of the gel oil,slows down oxidation and resists external pressure.(3)The emulsion gel formed by erythritol dioctanoate and palmitic acid and its properties.A camellia oil emulsion gel system was prepared using erythritol dioctanoate and palmitic acid as mixed gel.The optimum ratio of oil to water to form the stable structure of emulsion gel is 5:1.According to the polarizing microscope,fluorescence microscope and DSC detection results,the two kinds of crystals in the emulsion gel formed a network structure which maintained the stability of the emulsion gel.Moreover,the palmitic acid changed the crystal morphology and reduced the enthalpy of the whole system.The rheological test results show that the emulsion gel can resist the interference of external forces and maintain the stability of the structure.