Preparation And Characterization Of Sucrose,glucose And Lactose Fatty Acid Esters

Sugar fatty acid esters?SE?have been regarded as excellent food emulsifiers,possessing good emulsifying,foaming,wetting,dispersion,viscosity control,age-preventing and other properties.They have been widely used in the food,medicine,cosmetics as well as pharmaceutical industries.Although several types of SE have been developed,the sucrose ester is the major commercially available and widely used one.However,the development of novel sugar esters,such as those derived from glucose and lactose,are highly recommended.Since the domestic SE products are not competitive in the international market,there is an urgent need to develop new preparation methods for high quality sucrose ester and exploit other novel sugar esters to compete with foreign manufacturers.This thesis mainly studied sucrose esters,glucose esters and lactose esters which main contents and results are as follows:?1?Firstly,quantitative method for the standard curves of sucrose palmate monoester and stearate monoester was established by HPLC-ELSD,using water-methanol as mobile phases,which of peak time are respectively 7 min and 17 min.Additionally,sucrose ester products with high-purtity monoesters were synthesized by conventional chemical method and were optimized for single factor of temperature,pressure,catalyst and reaction time.The result showed that,the sucrose esters product with 74.1%content of monoester was obtained by mixing sucrose and methyl stearate in N,N-dimethylformamide under 100°C and 10 k Pa catalyzed by 5 wt%K₂CO₃for 3hours and purified by extraction,the purity is comparable to commercial Mitsubishi sucrose ester S-1670.Further more,this purity can be improved to ca.91.3%by optimizing the reaction condictions,i.e.,in the presence of certain commercial sufactants?potassium stearate and sucrose esters,for example?.The new method developed herein is suitable for large-scale industrial production and thus is of commercial importance.?2?Seven 6-O-acylglucose esters were parepared by an immobilized lipase,Novozym 435 catalyzed enzymatic transesterification of glucose and seven fatty acid vinyl esters?from 6 to 18 carbons?.Their hydrophilic-lipophilic balance values,foaming ability and stability,emulsion stability index as well as in vitro cytotoxicity were evaluated.The result demonstrated that when the length of the alkyl side chain associated with the 6-O-acylglucose esters increased,then their HLB values decreased,while the stabilities of the derived emulsions increased.In order to maintain good foaming properties,alkyl side chains of at least 10 to 12 carbons in length are required.Most of glucose monoestrs described herein were shown to be nontoxic to the Hep G2,MCF-7,LNacp,SW549,and LO-2 cell lines,meaning they have the potential to be used as green,safe emulsifiers in the food industry.?3?A homologous series of 6?-O-acyllactose esters of varying alkyl chain length?from 6 to 18 carbons?were prepared by an immbolized lipase,Lipozyme TL IM and were evaluated for their surface-active properties,in virto antimicrobial activity as well as cytotoxicity.The structure-property profiles established in this work revealed that while the medium-chain esters?C12 and C14?displayed excellent emulsifying properties and moderate antimicrobial activities,being superior to commercial sucrose ester and tween,span emulsifiers,their longer chain congeners?C14,C16,C18?exhibited certain cytotoxicities to MCF-7,A549,H1229,HEPG2-DOX and AC16cells.Moreover,most of those lactose esters seem to persistant to heat,revealing they are suitable emulsifiers for heating process of food.