Study On Synthesis And Properties Of Sucrose Fatty Acid Ester From Palm Oil By Two-step Method

Sucrose fatty acid ester is a kind of safe,non-toxic,biodegradable green non-ionic surfactants,with high and stable hydrophilic emulsification ability,as well as antibacterial,anti-tumor and insecticidal activities,it can be used in high-end cosmetics,food emulsifiers,pharmaceutical preparations and so on.The southern coastal areas of China are rich in palm oil,with high saturated fatty acid content and high oil yield.Moreover,Guangxi is the largest province of sucrose industry in China.Therefore,using palm oil as raw material to synthesize and optimize sucrose fatty acid ester is of great significance to promote sucrose deep processing industry in Guangxi..In this paper,palm oil and ethanol were used as raw materials,using esterification method to prepare ethyl fatty acid ester,and then sucrose and synthetic ethyl fatty acid ester as raw material,at the same time introducing mechanical activation technology,and using solvent-free method to prepare sucrose fatty acid ester with low esterification degree,and optimize the process conditions.It was characterized by Fourier Transform infrared spectroscopy(FTIR)and thin layer chromatography(TLC).The physicochemical properties and practical applications of sucrose fatty acid ester were also investigated.The main research contents are as follows:(1)Ethyl ester of palm oil fatty acid was synthesized by transesterification reaction with palm oil and ethanol as raw materials under the action of catalyst sodium hydroxide.The physical and chemical indexes of raw palm oil were measured,and the average molar mass of palm oil was 828.31 g/mol.The results showed that the transesterification reaction of palm oil with ethanol was feasible.When the molar ratio of alcohol to oil was 7:1,the amount of catalyst was 0.8 wt.%(for palm oil),the reaction temperature was 75℃,and the reaction time was 75 min,the yield of palm oil fatty acid ethyl ester was 95.6%.FTIR analysis showed that the product of palm oil esterification was palm oil fatty acid ethyl ester.TLC analysis showed that the esterification reaction was sufficient and the conversion rate was high.(2)Using the ethyl fatty acid synthesized in the first step and mechanically activated sucrose as raw materials,adding potassium carbonate as catalyst,stearic acid as emulsifier,and sucrose fatty acid ester was synthesized by solvent-free method under vacuum condition.When the molar ratio of sucrose was 3:1,the amount of catalyst was 4.0wt.%,the amount of emulsifier was 10 wt.%,the reaction temperature was 140℃,and the reaction time was 5 h,the esterification degree of refined sucrose fatty acid ester was 1.25 and the yield was 82.0%.After 20 min of mechanical activation,sucrose particle size distribution was 95.07～198.0 nm,average particle size was 101.0 nm,and yield was increased by 92.3%.The results of FTIR and ~1H-NMR showed that the ester exchange reaction occurred between ethyl fatty acid and activated sucrose.TLC results showed that the content of monoester of self-made sucrose fatty acid ester was higher,and there was a small amount of diester.TGA results showed that sucrose fatty acid ester had better thermal stability.SEM results showed that sucrose fatty acid esters were layered.And its free sugar,acid value,ash and other indicators were up to the international standard.(3)The properties and application of sucrose fatty acid ester were analyzed.The HLB value of sucrose fatty acid ester(n=1.25)was 15.5.SE-7 has the best foaming performance,and SE-9 has the best foam stability and has good wettability.Hydrophilic sucrose fatty acid ester and lipophilic sucrose fatty acid ester had good solubility in polar solvent and non-polar solvent respectively.The sucrose fatty acid ester prepared from palm oil had good antibacterial effect,and staphylococcus aureus was stronger than escherichia coli.When the mass fraction was greater than the critical micelle concentration(CMC),the surface tension was almost unchanged.The matching between sucrose fatty acid ester and n-hexane was better than that of liquid paraffin.It can improve the foaming ability of pure milk and emulsification ability of coconut milk,and has excellent oxidation stability.