Preparation And Properties Of Octenyl Succinic Anhydride Modified Waxy Wheat Starch

This thesis studied preparation of Octenyl succinic anhydride (OSA) modified starches from raw material waxy wheat starch in aqueous slurry system. Some properties of the OSA starch were also investigated in this thesis, including the viscosity, clarity, retrogradation, freeze-thawing stability of the starch paste, and emulsification property of the OSA starch. Then the effect of the OSA starch on the cracking rate of deep-frozen dumpling peel was investigated in this thesis.At first, study the effect of different reaction conditions on the degree of substitution (DS) of the OSA starch, such as the concentration of starch slurry, pH range, reaction temperature, reaction time. On the base of single factor analysis result, response surface analysis was done with design expert software and the optimistic condition of synthesizing was obtained. The optimistic condition of synthesizing was that: the concentration of starch slurry 31.3%, pH 8.6, reaction time 3h, reaction temperature 30.6℃. At this condition, the degree of substitution (DS) is 0.0144.Secondly, research the structure of the OSA starch. FT-IR spectroscopy verified that native starch reacted with OSA and the ester carbonyl is in the OSA starch. X-ray analysis showed that the OSA starch occurred mainly in amorphous molecular areas and still maintained the same crystalline pattern as native starch. DSC analysis revealed that though the OSA starch maintained the same crystalline pattern as native starch, the starch granule swelled at a certain extent and the compact degree of crystalline pattern descended, so SSOS gelatinize more easily. Synchrotron radiation X-ray diffraction analysis showed that the main crystal-lattice tactic of SSOS didn't change in reaction and this aggregate structure had responsiveness to chemical reaction.After, investigate the properties of the OSA starch. The results showed that the OSA starch paste had higher peak viscosities, HPV and CPV than native waxy wheat starch. Moreover, the degree of substitution(DS) is increased, the PV, HPV and CPV of OSA starch paste increased, but the peak time decreased; Comparing with native waxy wheat starch, the paste clarity, retrogradation and freeze-thaw stability of OSA starch had enhanced, and more, as the DS was getting higher, the paste clarity, retrogradation and freeze-thaw stability of OSA starch was better; The paste clarity and retrogradation of OSA starch greatly decreased by the presence of sodium chloride, but only increased slightly in the presence of sucrose; Emulsification property of the OSA starch increased with DS increasing.At last, work over the effect of the OSA starch on the cracking rate of deep-frozen dumpling peel. When the degree of substitution of the OSA starch increased, the cracking rate of deep-frozen dumpling peel decreased. Moreover, the cracking rate of deep-frozen dumpling peel decreased with the addition of the same DS starch increasing.