Preparation And Properties Of High-viscosity Carboxymethyl Etherified And Octenyl Succinate Esterified Starch

This research was aimed at preparing high-viscosity carboxymethyl etherified octenyl succinate binary dual-modified starch with emulsification and thickening function.The optimal conditions for the preparation of carboxymethyl were studied,and starches from different plant sources were studied.In this study,carboxymethyl starch was used as a raw material to react with octenyl succinic acid anhydride to prepare carboxymethyl and octenyl succinic acid dualmodified starch,and the properties and applications of it were systematically studied.The specific content is as follows:The optimal preparation conditions of carboxymethyl starch as raw material of carboxymethyl and octenyl succinic acid binary dual-modified starch were studied.Carboxymethyl starch prepared under the condition of acid-base molar ratio 1:1.5 was more suitable as the raw material for preparing high-viscosity dual-modified starch;carboxymethyl starch prepared under the condition of acid-base molar ratio 1:1.5 and the amount of monochloroacetic acid 35% The product had the highest viscosity after reacting with OSA;FTIR analysis shows that single carboxymethyl starch,octenyl succinic acid starch and dualmodified starch were successfully prepared;SEM picture analysis showed that the acid-base molar ratio was 1:1.5 The carboxymethyl starch obtained under the condition of good integrity,acid and alkali did not cause obvious corrosion to the starch granules,and the morphology was close to the original starch;XRD analysis showed that the relative crystallinity of the carboxymethyl starch obtained under the condition of the acid-base molar ratio of 1:1.5decreased less;Viscosity analysis showed that the carboxymethyl starch prepared under the acid-base molar ratio of 1:1.5 had the same trend of viscosity change as the carboxymethyl starch prepared under the acid-base molar ratio of 1:2,and the maximum viscosity was obtained at the degree of substitution of 0.23.The properties of carboxymethyl and octenyl succinic acid binary dual-modified starch prepared from different plant-derived starches were studied.After dual-modification of starches from different plant sources,the viscosity had been significantly increased.The maximum viscosity of waxy corn was 102,500 m Pa·s;SEM observed the different changes of the four starches after treatment.The starch with intact granules had relatively higher viscosity;XRD observed that the relative crystallinity of the four native starches decreased after carboxymethylation treatment,and the relative crystallinity increased after the octenyl succinate dual modification;after the binary dual modification,the starch emulsification and emulsification stability were improved.Potato starch and waxy corn starch had the best emulsification performance after dual modification;the dual-modified starch had excellent anticoagulation properties,and the starch paste solution did not appear delamination after being placed for ten days phenomenon.The optimal preparation process of carboxymethyl and octenyl succinic acid binary dualmodified starch was studied.In the single-factor experiment,the highest single-factor viscosity conditions were as follows: the volume fraction of the reaction solvent ethanol is 95%,the reaction temperature was 25°C,the reaction p H was 6.5,the amount of OSA was 30%,and the reaction time was 5 h;the preparation was optimized by orthogonal experiment.The optimal process conditions of high-viscosity carboxymethyl and octenyl succinic acid binary dualmodified starch were: reaction temperature 30?,reaction p H was 7.0,OSA dosage 35% and reaction time 5 h,and finally composite modified starch was obtained.The viscosity was 83,200 m Pa·s,which effectively optimizes the process conditions.The properties and application of carboxymethyl and octenyl succinic acid dual-modified starch with high viscosity and emulsifying and thickening function were studied.Dual-modified starch was fully dissolved in cold water,the dissolution time was short,the dissolution was uniform,the paste viscosity was large;SEM showed that the starch particles with the highest viscosity prepared were complete,the surface was smooth,and there was no collapse and corrosion,and the starch particles were well protected under this reaction condition.The XRD pattern showed that the dual-modified starch produced sub-microcrystals,which had higher diffraction peak strength and relative crystallinity than carboxymethyl starch.The test of anticoagulant property showed that the anticoagulant property of the dual-modified starch prepared by the optimal process conditions was better than that of the original starch.The salt resistance test showed that the dual-modified starch had poor salt resistance and was not suitable for high concentration salt solution.The emulsification tests showed that the emulsification properties of carboxymethyl starch and dual-modified starch were both improved compared with the original starch.The emulsification properties of dual-modified starch prepared by the optimal process conditions were not improved compared with carboxymethyl starch.The thermogravimetric analysis showed that the thermal stability of the original starch became worse after modification.In the consistency test,the dual-modified starch with 6%concentration had a good consistency of 10.9 cm.The putty made from compound modified starch has good paste shape and no fluidity,and can be formed well.The paste is thick and can be used in combination with liquid paraffin wax,so it is suitable for the application of putty additive.