Study On The Preparation And Properties Of Cross-linked And Cross-linked-Octenyl Succinic Anhydride Modified Starch Prepared With Different Materials

Starches were modified by cross-linking with sodium trimetaphosphate (STMP)/sodium tripolyphosphate(STPP) and esterification with octenyl succinic anhydride (OSA) in this paper. Six kinds of starches were chemically modified using single (cross-linking and esterification) and dual modification (cross-linking-esterification and esterification-cross-linking), with the objective to choose material and modified method. Resistant starch (RS) concentrations had been used as a selection criterion and cross-linked octenyl succinic anhydride potato modified starch (CLOSA-PS) was selected as object of study. Effects of the amount of cross-linking agent, cross-linked pH, reaction temperature and reaction time on the combined phosphorus content were studied. The optimal reaction conditions were determined. A series of modified starches with different degrees were prepared by changing the amount of cross-linking agent and esterification agent which was based on the optimal reaction conditions. Therefore the aim of this study was to analyse the properties of products with different degeneration.1. Through the research on these modified starches the results showed that:①The physicochemical properties of potato starch were better than those of native starch; The esterified samples had the better properties compare to cross-linking, cross-linking-esterification and esterification-cross-linking (the highly cross-linked starches were non-gelatinization starches); The esterified potato starches had the best properties in all of those modified starches②The native potato starch had the lowest RS content,whereas the cross-linked octenyl succinic anhydride potato modified starch (CLOSA-PS) had the highest RS concent of17.21%.2. Effects of the amount of cross-linking agent, cross-linked pH, reaction temperature and reaction time on the combined phosphorus content were studied. Response surface methodology was employed to optimize the process variables of the major factors. The regression equation of the combined phosphorus content is: the combined phosphorus content=0.11+0.017A+0.049B+0.042C+3.913E-003D+0.013AB+0.012AC-8.040E-004AD+0.016BC+1.237E-003BD+3.721E-003CD +2.952E-003A2+3.509E-003B2+6.469E-003C2-7.898E-003D2The order of factors which influenced on the combined phosphorus content was: reaction pH> temperature> the mount of cross-linking agent> time. The optimal reaction conditions were determined as follows:the amount of cross-linking agent16%, reaction time4.5h, cross-linked pH11.5and reaction temperature55℃. According to this condition, the combined phosphorus content was up to0.551%.3. Based on the researches of the different modify degrees, the results showed that:①In view of cross-linked potato modified starch (CL-PS), the combined phosphorus content increased with increase of the mount of cross-linking agent. When the mount of cross-linking agent was19%, the the bound phosphours was up to0.7%; The degree of substitution (DS) of the esterified samples increased as the mount of OSA rised.②The amount of total resistant starch increased with increasing the combined phosphorus content. The amount of total resistant starch was22%,while the mount of cross-linking agent was19%and the the bound phosphours was0.7%; In dual modified potato starches, the amount of total resistant starch improved with increasing DS. When the mount of OSA ranged from1%to9%, the CLOSA-PS showed an increase in RS from14%to29%.③Cross-linking reduced the transparency and the swelling power while increased retrogradation with increasing the combined phosphorus content. There were no significant differences in all of CL-PS on the emulsion stability; The CLOSA-PS had better physicochemical properties than CL-PS.