Synthesis And Properties Of Sucrose Palmitic Acid Polyester

Sucrose fatty acid polyester has good application prospects in food,cosmetics and other fields because of its special molecular structure and physical and chemical properties.In this paper,sucrose palmitic acid polyester(SPE)was synthesized by solvent and solvent-free method.In order to solve the compatibility problem of reactants,sucrose palmitic acid low ester(SE)was first synthesized,and residual sugar and colored impurities in SE were removed to avoid the caramelization of sucrose.Then highly esterified product was synthesized by using SE as acyl acceptor,and its properties were investigated.The main works are listed as follows:SE was synthesized by solvent method at low temperature.By single factor experiments,the optimal synthetic conditions were determined as follows:molar ratio of ester to sugar of3:1,a catalyst(potassium carbonate)amount of 4%,a solvent amount of 6 V/m(a ratio of solvent volume to sucrose mass),temperature of 95�C,pressure of 25 KPa and a time of 9 h.The crude product was purified by thermal extraction,and analyzed by IR,~1H NMR,TLC and HPLC-ELSD.The yield of SE was 93.52%,the average esterification degree was 2.54,and the content of low esters was 80.97%.SPE was synthesized under solvent-free conditions using SE as acyl acceptor.The reaction process was monitored by hydroxyl value.By single factor experiments,the optimal synthetic conditions were determined as follows:a material ratio(the molar ratio of sucrose palmitic acid low ester to methyl palmitate)of 7:1,a catalyst(potassium carbonate)amount of 3%,temperature of 125�C and a time of 6 h.The product was waxy solid with a color of white to milky white,the yield was 70.28%and average esterification degree was 5.94 under these conditions.The analysis of IR,~1H NMR,TLC,ESI-MS,MALDI-MOF-MS and HPLC-ELSD showed that the content of lower esters was 8.18%,and with polyesters as main components in the product.The solubility and emulsifying properties of SPE were investigated.SPE has good solubility in oil and is an excellent water-in-oil emulsifier.The emulsifying ability of SPE was better than commercial emulsifiers of Span series,and the water content in stable emulsion can reach up to 75%.