无籽刺梨渣可溶性膳食纤维硫酸酯化改性及性质分析

以无籽刺梨渣可溶性膳食纤维(Rosa sterilis Soluble Dietary Fiber,RSDF)为原料,取代度为评价指标,对RSDF进行硫酸酯化改性(氨基磺酸-N,N二甲基甲酰胺法),制取硫酸酯化无籽刺梨渣可溶性膳食纤维(Sulfated Soluble Dietary Fiber,SSDF)。探究料液比(g/mL)、氨基磺酸比(g/g)、反应时间(min)以及反应温度(℃)对取代度影响,并进行4因素3水平正交试验,获取最佳酯化工艺,最后采用红外光谱与差示扫描量热对比分析RSDF与SSDF差异。结果表明,硫酸酯化最佳条件为料液比1:80 g/mL、氨基磺酸比1:4 g/g、反应时间195 min和反应温度80℃,此条件下SSDF的取代度为1.84±0.19。红外光谱表明经硫酸酯化改性后SSDF在1254 cm^-1与893 cm^-1处出现了硫酸酯化物的特征峰,表明硫酸酯化成功。差示扫描量热分析表明经改性后SSDF的熔融温度为140℃,热稳定性略低于RSDF。

Sulfation Modification and Properties Analysis of Soluble Dietary Fiber from Rosa sterilis Pomace

In this paper, the Rosa sterilis soluble dietary fiber (RSDF) was used as raw material. The degree of substitution was used as the evaluation index, the RSDF was modified by sulfate esterification (Sulfamic acid-N,N-dimethylformamide method) and prepared sulfated soluble dietary fiber (SSDF). The influence of RSDF and N,N-dimethylformamide solid-liquid ratio (g/mL), RSDF and sulfamic acid ratio (g/g), reaction time (min) and reaction temperature (℃) on the degree of substitution were investigated, and three levels of the four single factors were selected for orthogonal test to obtain the best esterification process. Finally, the difference between RSDF and SSDF was analyzed by infrared spectroscopy and differential scanning calorimetry. The results showed that the optimal conditions were solid-liquid ratio of 1:80 g/mL, sulfamic acid ratio of 1:4 g/g, reaction time of 195 min and reaction temperature of 80 ℃. Under these conditions, the substitution degree of SSDF was 1.84±0.19. Infrared spectrum showed that the characteristic peak of SSDF at 1254 cm?1 and 893 cm?1 appeared after the sulfated modification, indicated that the sulfated was successful. Differential scanning calorimetry analysis showed that the melting temperature of SSDF was 140 ℃ and its thermal stability was slightly lower than RSDF.