Study On The Preparation Of Ester Modified Sweet Potato Starch And It's Physical And Chemical Properties

In this paper, firstly, the preparation of acetylation sweet potato starch (AC-BSPS) and octenyl succinate sweet potato starch (OSA-BSPS) were be studied. Secondly, comparpered some physical and chemical properties of this two esterification modified starch. Finally, on the basis of AC-BSPS, OSA-BSPS and the properties of modified starch. The double esterification of sweet potato starch (AC-OSA-BSPS) was prepared and its physical and chemical properties were studied. All of this was the objective that developing sweet potato processing industy and providing multiple esterification theory. The results are as follows:First, by using response surface experimental design method, studying the amount of acetic anhydride (A), pH(B), and reaction time (C) on the AC-BSPS's DSAC influencement, the mathematical regression model was DSAC= 4.26259+0.047525A+0.93373B+0.088844C-(4.51667E-003) AB+ (1.79167E-004) AC-0.010950 BC-(7.50000E-005) A2-0.050200 B2-(2.25000E-004) C2. Through optimization, the optimal conditions preparation of AC-BSPS obtained were:15% addition of acetic anhydride, the reaction pH was 8.0, reaction time 6h, prepared by the above conditions can be obetain DSAC expected value is 0.164 AC-BSPS. By use of response surface experiment design, analysis OSA dosage (X1), pH (X2), temperature (X3) and reaction time (X4) on the OSA-BSPS's DSosa influencement. The mathematical regression model was DSOSA= 0.027+ (7.358E-003) X1-(2.300E-003) X2-(6.500E-004) X3+ (1.542E-003) X4-(8.750E-004) X1X2-(4.000E-004) X1X3+(1.350E-003) X1X4+(3.750E-004) X2X3+(4.000E-004) X2X4-(1.250E-004) X3X4-(1.033E-004) X12-(7.666E-003) X22-(2.266E-003) X32-(2.003E-003) X42. By optimizing, the optimal OSA-BSPS preparation process for this:OSA dosage was 7%, pH value of 8.40, the temperature was 40℃and the reaction time was 10h. By the above reaction conditions, the DSOSA could be 0.0358.FT-IR analyse these starches. AC-BSPS on 1735.00cm-1 appears a significant carbonyl peak. OSA-BSPS on 1720.99 cm-1 peak was the ester carbonyl groups's exist and on 1578.18 cm-1 peak was the asymmetric stretching vibration of RCOO-. AC-OSA-BSPS's peak was at 1732.36cm-1 and 1578.31 cm-1. The 1732.36cm-1 was the carbonyl mainly caused by acetylation,1578.31 cm-1 esterification mainly caused by OSA. The analysis of AC-BSPS, OS A-BSPS, AC-OSA-BSPS's viscosity characteristics showed that:AC-BSPS peak viscosity increased with the DSAC increased, but when DSAC exceeds a certain range, the peak viscosity decreased, even lower than BSPS; OSA-BSPS relatively close to the peak viscosity of SPS, and increased with the DSOSA increased, but the tendency was not obvious; AC-OSA-BSPS peak viscosity is generally higher than BSPS, SPS, AC-BSPS, OSA-BSPS. When DSOSA varyed lessly, with the DSAC increased, the AC-OSA-BSPS show a peak viscosity increasing tendency. However, when the DSAC varyed lessly, with the DSOSA increases, the peak viscosity increased, but not obvious. In addition, Acetylation, OSA esterification and dual esterification were significantly reduced BSPS, SPS initial gelatinization temperature.Finally, three esterification starches's properties indicate that Acetylation increased light transmission at a limited role, when its DSAC over a certain range, the retrogradation even greater than the SPS and the BSPS, AC-BSPS the freeze-thaw stability better than SPS, BSPS, with DSAC increased, the freeze-thaw stability is better, but when its over a certain range, AC-BSPS will appear water gradually, AC-BSPS does not exist emulsification; OSA estertion can significantly increase the light transmission, there is almost no retrogradation phenomenon, OSA-BSPS almostly was not water between the selected time, can withstand freezing and thawing repeatly, emulsification increased with DSOSA enhanced; AC-OSA-BSPS's transmittance was higher than BSPS and SPS, between AC-BSPS and OSA-BSPS, AC-OSA-BSPS retrogradation weak, AC-OSA-BSPS's freeze-thaw stability was good. The preparation that lower acetican hydrideand the higher OSA, AC-OSA-BSPS have a certain amount of emulsifying properties.