Preparation Of High Viscosity Carboxymethyl Starch And It’s Application In Instant Rice Porridge

This paper is divided into three parts: First, with corn starch as raw material, preparehigh viscosity carboxymethyl starch via etherification of chloroactic acid; Second, study thetechnology conditions of the preparation of instant rice porridge aim at the difficulties such asthe rehydration of instant rice porridge; Third, to achieve a better palatability, mainly researchthe application of high viscosity carboxymethyl in instant rice porridge to improve somecharacteristics of instant rice perridge.The high viscosity carboxymethyl starch was prepared with the method of addingsodium hydroxide by twice steps in alcohol-water media.The effect of reactiontemperature,reaction time,the amount of sodium hydroxide,the concentration ofalcohol,liquor/starch ratio,the amount of monochloroacetic acid,etc were studied.Based onaforementioned analysis,the highest viscosity of substitution was found by Design-Expert thatat the time of basification the molar ratio of the sodium hydroxide to AGU of0.44,the molarratio of the monochloroacetic acid to AGU1.10,at the time of aether the molar ratio of thesodium hydroxide to AGU of0.20,the reaction temperature at60℃, the etherification time of3.0h, liquor/starch ratio of3.0, the concentration of alcohol was85%.The carboxymethylstarch with the viscosity of25974mp.s was obtained.The carboxymethyl starch was analysedby infrared absorption,X-ray diffraction and SEM.The portion of starch hydroxy groups weresubstituted after etherification by analysis.The components and characteristics of raw rice were analysed and the quality evaluationsystem for convenient rice porridge was established. The essential technological process ofpreparation convenient rice porridge is washing the raw rice;the first immersion;the firstcooking;the second immersion; the second cooking;discrete;microwave drying and otherproceses. Distilled monoglycerides, trehalose, sodium tripolyphosphate, sucrose ester andother additives are selected in the first immersion to study the influence on the rate ofrehydration with different content. The orthogonal experiment were made and the optimaladditions were: Monoglycerides0.3%, trehalose0.2%, sodium tripolyphosphate0.25%andsucrose ester0.2%. In these conditions, The rehydration of convenient rice porridge showedthe best performance. The neutral protease and cellulase other additives are selected in thesecond immersion. to conduct enzyme liquid immersion. The orthogonal experiment weremade and the optimal conditions were: protease4000U/100g rice, cellulase200U/100g rice,the addition of the water is1.4times the quality of rice at constant temperature50℃ with30min. Finally a complete program to prepare convenient rice porridge of betterrehydration was obtained.On the basis of the first two parts,the influence of different additions of high viscositycarboxymethyl starch on the characteristics of convenient rice porridge were studied.The timeof immersion,the addition of CMS when drying and rehydration after drying were selected tosrudy the influence on qualities of convenient rice porridge.The method of specific additionwas determined after qualities evaluating.At the same time, the rehydrated photo analysis andscanning electron microscopy observation of the microstructure of convenient rice porridgewere conducted.