Lipase-catalyzed Synthesis Of Maltose Fatty Acid Esters And The Study Of Its Emulsifying Property

In this article, enzymatic synthesis of maltose fatty acid ester was performed, and purification and detection methods had been studied. Its testing standards were developed, and properties of maltose fatty acid ester were determined. Then the application of it, as emulsifiers, was studied. And we determined the safety of maltose fatty acid ester toxicity level by acute toxicological tests.The highest yield (90%) was obtained when the reaction mixture consisted of t-butyl alcohol,30mmol/L of maltose, the molar ratio of myristic acid/maltose of5:1,6g/L enzyme at60℃for60h. Also in solvent of t-butyl alcohol, the molar ratio of stearic acid/maltose of5:1,8g/L enzyme60℃for72h, the highest yield (87%) was obtained for synthesis of stearoyl maltose.The method extraction choosing methyl ethyl ketone-salt solution was used to remove the maltose with the salt concentration of10%washing3times. Hexane was used to centrifuge (4000r/min forlOminm, twice) to remove fatty acid, the amount of which was1/2volume of reaction solution. After regular temperature drying, white or yellow sticky solid sugar esters could be obtained.The absorption band of the ester bond (1726cm-1) appeared after the analysis of IR, which proved that maltose esters were synthesized. The samples were analysized by LC-MS analysis. And the molecular weight of myristoyl maltose and stearoyl maltose analysis was obtained, further evidence of synthesis of maltose esters.Considering about chemical structure, maltose esters are basically the same to sucrose esters. So maltose ester was detemined based on detection of GB projects of sucrose ester, including7indexes such as:fatty acid residue, dimethylformamide, arsenic, heavy metals, free sugars, water, ash. Due to the characteristics of synthesis of emaltose ester, the determination of residual solvents was detected. Test results showed that the7indexes were all reach the standard of sucrose esters.Properties of maltose fatty acid ester were studied including:(1) HLB,(2) surface tension and critical micelle concentration,(3) emulsifying activity,(4) thermal properties,(5) antimicrobial activity,(6) SEM and AFM,(7) the microscopy of emulsion of sugar ester.The emulsifying property of maltose fatty acid ester was tested, selecting fat-rich walnut milk beverage stabilizing effect as controlled experiments. Finally we got the ratio of emulsion stabilizer:monoglyceride/maltose ester=1/2, addition amount of0.4%, xanthan gum0.05%, CMC-Na0.05%, sodium alginate0.1%.The acute toxicity test of maltose fatty acid ester:fed rats of both sexes under the dose15.3g/kg BW, and observed for14days, no obvious symptoms of poisoning and no death appeared. We could see that the MTD oral acute toxicity in rats was more than15.3g/kg bw. The maltose fatty acid ester was nontoxic substances based on acute toxicity rating.