| Synthesis of carboxymethyl starch stearate (CMSS), carboxymethyl starch laurate(CMSL) and carboxymethyl starch hexanoate(CMSH) was studied under microwaveirradiation in this paper, in which stearic acid, lauric acid and hexanoic acid was used asesterifying agents respectively, and carboxymethyl starch (CMS) as raw material, thenstructure and properties of carboxymethyl starch-fatty esters (CMSFE) was compared. At last,preliminary research on the application of CMSFE in Chicken paste was conducted.Firstly, the process condition of CMSFE synthesis by assistance of microwave irradiationwas explored.With stearic acid, lauric acid and hexanoic acid used as esterifying agentsrespectively, the optimum process conditions of CMSFE was determined according to thesingle factor experiments and orthogonal test. The optimum process conditions (according todry basis)of CMSS: CMS30g(dry basis), mass fraction of HCl0.121%, microwave power700W, water mass fraction26%, microwave time5min,ethanol content16mL/10gCMS,content of stearic acid3%, the DS of stearic acid in the obtained product was0.0120, with thereaction efficiency63.27%. The optimum process conditions (according to dry basis)ofCMSL and CMSH were the same with CMSS, in addition to the water mass fraction of wereall34%, and in the obtained CMSL and CMSH, the DS of fatty acid were0.0127and0.0088respectively, with the reaction efficiency47.24%and19.06%.Secondly, the structure of the hydrophobic CMS was studied. The structure of CMSLwasinvestigated by FTIR Spectrometer and NMR instrument, and the Infrared analysis indicatedthat, in the process of esterfying, protonation of CMS also happened, so that the peak ofcarbonyl of ester bond formed by esterfication was overlapped by the peak of protonatedcraboxymethyl groups, and the results of1H-NMR spectra suggested that long carbon chainwas present in the CMSL, which confirmed the success of esterification.Thirdly, the influence of the length of carbon chain on the properties of CMSFE wascompared. The thickening and emulsifying properties were mainly studied, and the resultsindicated that viscosity, G’, G’’ and thixotropy values of CMSFE all increased, the longer thecarbon chain, the greater the values. Emulsification and emulsion stability of CMSFE wereimproved greatly, the longer the carbon chain, the better the emulsifying property. In addition,surface activity, retrogradation and thermo-stability of CMSFE were studied, and the resultsproved that, compared to CMS, after modified, the surface tension of CMS were lower, andthe lowest CMC was CMSH, followed by CMSL and CMSS. Retrogradation decreased, thelonger the carbon chain,the lower the value, and thermo-stability improved.Lastly, the preliminary study on the application of CMSFE in chicken paste was carriedon, in which CMSFE was used as thickener and emulsifier. According to texture and rheological analysis, the homemade chicken paste, which was close to commercial product,can be prepared, when the mass fraction of CMSL was5%. In the process of storage, relevantindicators of homemade chicken paste made a smaller change, compared to commercialproducts, and the surface state was always thick and bright, which indicating that thehomemade chicken paste had storage stability to some extent.The fioating oil study showedthat the oil slick and stratification could be improved effectively, when CMSFE with longercarbon chain was added into the homemade chicken paste. |
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