共查询到17条相似文献,搜索用时 218 毫秒
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羟丙基马铃薯淀粉合成工艺及性能研究 总被引:9,自引:3,他引:9
本文以马铃薯淀粉为原料,环氧丙烷为醚化剂,氢氧化钠为催化剂对低取代度羟丙基淀粉的制备工艺进行了研究。考察了环氧丙烷用量、氢氧化钠用量、反应时间、反应温度对羟丙基淀粉取代度的影响。实验结果表明,提高环氧丙烷用量、氢氧化钠用量、反应时间和反应温度可提高羟丙基淀粉取代度,硫酸钠用量对羟丙基淀粉取代度有影响。采用分光光度法测定了羟丙基淀粉取代度。 相似文献
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以糯玉米淀粉为原料,环氧丙烷为醚化剂,在碱性条件下对羟丙基淀粉的制备工艺及其性质进行了研究.考察了醚化剂、膨胀抑制剂、pH、反应温度、反应时间对羟丙基淀粉取代度和反应效率的影响.实验结果表明,随着pH的增大,羟丙基淀粉的取代度和反应效率都增大;提高反应温度,羟丙基淀粉的取代度和反应效率都增加;增加环氧丙烷的用量,羟丙基淀粉的取代度随之增加,但反应效率呈下降的趋势;延长反应时间,淀粉的取代度和反应效率都呈上升趋势;增加硫酸钠的用量,羟丙基淀粉的取代度和反应效率都先增大,当硫酸钠用量超过12g时,随着硫酸钠用量的增加取代度和反应效率都降低.并且确定出最佳的反应条件:淀粉用量为100g时,pH为11.5,膨胀抑制剂12g,环氧丙烷10mL,反应温度50℃,反应时间20h.随着羟丙基糯玉米淀粉取代度的增加,其冻融稳定性、透明度、耐酸性、黏度热稳定性都增加. 相似文献
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采用相转移催化法制备了羧甲基壳聚糖,考察了催化剂种类、催化剂使用量、反应温度、反应时间和溶剂中水醇比对羧甲基壳聚糖取代度(DS)和溶解性的影响。得到最佳反应条件为:以6% 的苄基三乙基氯化铵(TEBA)作催化剂,反应温度55℃,反应时间4h,溶剂中水醇比1:4(V/V),羧甲基壳聚糖的取代度(DS)和溶解率分别达到1.147 和98.87%。并采用傅立叶红外光谱法及X 光电子能谱分析法对产物结构进行了表征,结果表明壳聚糖羧甲基化反应主要是发生在C6 位上的- OH 基团上。 相似文献
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壳聚糖羧甲基化条件的优化 总被引:7,自引:0,他引:7
对壳聚糖的羧甲基化条件进行了优化。通过单主正交试验,考察了氯乙酸用量、碱化时间、反应温度对产品羧甲基取代度、外观等理化指标的影响,得出羧甲基化的最佳条件为:碱化时间2.5h,羧甲基化反应时间4h,反应温度40℃,4M氯乙酸用理70ml,制备的羧甲基壳聚糖呈白色粉末,羧甲基取代度达0.898,水溶性较壳聚糖有较大改善。 相似文献
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以木薯淀粉为原料,环氧丙烷为醚化剂,硫酸钠为淀粉膨胀抑制剂,采用湿法工艺制备木薯羟丙基淀粉,以产品摩尔取代度(MS)为评价指标,通过单因素试验分别探讨了环氧丙烷用量、硫酸钠用量、反应pH值、反应温度、反应时间等对羟丙基醚化反应的影响,在此基础上应用正交试验确定了木薯羟丙基淀粉制备的最佳工艺条件。试验结果显示:(1)随环氧丙烷用量的增大,取代度逐渐升高,反应效率逐渐降低;(2)适当提高反应pH和反应温度有利于取代度的提高,但反应pH值超过11.5和反应温度超过45℃,会导致淀粉的局部糊化,不利于醚化反应的进程。制备木薯羟丙基淀粉的最佳工艺条件为:淀粉乳浓度40%,环氧丙烷添加量10%(对干基),硫酸钠添加量12%(对干基),反应pH值11.5,反应温度40℃,反应时间22 h。所得木薯羟丙基淀粉的取代度为0.143。 相似文献
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超声波作用对玉米淀粉羟丙基化的影响 总被引:2,自引:0,他引:2
超声波技术是一种常用的物理加工处理方法,目前将超声波技术用于淀粉改性成为新型变性淀粉的研究热点。本文以玉米淀粉为原料,考察了超声功率、超声时间、淀粉浓度、环氧丙烷用量对其羟丙基化的影响。结果表明:在超声波的作用下,随着超声功率的增加、超声时间的增长、环氧丙烷用量的增加、淀粉浓度的增加,玉米淀粉羟丙基化的取代度呈现先增大后减小的趋势。通过正交实验获得了制备羟丙基玉米淀粉的最优工艺条件为:超声功率600W、超声时间20min、淀粉浓度35%、环氧丙烷用量4.8%,在该条件下于50℃反应4h制备的羟丙基玉米淀粉的取代度为0.4。 相似文献
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羟丙基糯玉米淀粉合成工艺及性能研究 总被引:3,自引:2,他引:3
本文以糯玉米淀粉为原料,以环氧丙烷为醚化剂、氢氧化钠为催化剂、硫酸钠为抑制膨胀剂,对糯玉米羟丙基淀粉合成工艺及其性能进行了研究,探讨了糯玉米淀粉乳浓度、环氧丙烷用量、反应时间、反应温度、氢氧化钠用量及硫酸钠用量对糯玉米羟丙基淀粉取代度和反应效率的影响。实验结果表明,增加环氧丙烷用量、延长反应时间,可使羟丙基淀粉取代度增加。对糯玉米羟丙基淀粉的冻融稳定性、透明度及粘度进行研究表明,随着羟丙基糯玉米淀粉取代度的增加,其冻融稳定性和透明度增加,但粘度却降低。 相似文献
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Lixia Wang Xianghua Liu Jingzhen Wang 《International Journal of Food Properties》2017,20(6):1239-1250
Modified yam starch and dual-modified yam starch were produced with propylene oxide, sodium trimetaphosphate and sodium tripolyphosphate. Gelatinization temperature and final viscosity of native yam starch were 79.2 ± 0.4°C and 5702 ± 3 cP. Results showed that the molar substitution and degree of substitution were increased with the volume fraction of propylene oxide from 6–12%, the highest of molar substitution and degree of substitution were 0.0445 ± 0.0003 and 0.0065 ± 0.0006, the final viscosity and setback of dual-modified yam starch were also similar. However, the gelatinization parameters showed an inverse trend. Starch modified with a mixture of sodium trimetaphosphate and sodium tripolyphosphate had higher phosphorus content and increased viscosity compared to starch modified with sodium trimetaphosphate. The peak viscosity of starch modified with propylene oxide was higher than that of native yam starch and the highest was HP12. The granular surface of modified yam starch and dual-modified yam starch appeared significantly embossed and indented, while. Modified yam starch film treated with 12% propylene oxide showed a more homogeneous fractured surface. The tensile strength and elongation at break (E) of starch films were affected by crosslinking reagents and propylene oxide, respectively. The best transparence and E were demonstrated in starch film that was modified with 12% propylene oxide. However, the best tensile strength was demonstrated in starch film that was modified with 8% propylene oxide, sodium trimetaphosphate, and sodium tripolyphosphate. The final viscosity of HP6C1 and HP6C2 was 27 ± 7 and 45 ± 9 cP, which was too low to form film. 相似文献
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Carboxymethyl chitosan is a chitosan derivative of the most intensively investigated due to its water solubility in wider pH range compared with the parent compound, thus extended its use in various applications. In this review, different preparation conditions, which resulting in the N‐ and O‐carboxylated chitosan, diverse degree of substitution and water solubility are recapitulated. Five important features of carboxymethyl chitosan from recent studies, which are moisture absorption–retention, anti‐microbial properties, antioxidant capacities, delivery system and emulsion stabilization, have been centred and emphasized for cosmetic utilization. Additionally, cytotoxicity information has been inclusively incorporated to ensure its safety in application. 相似文献