蒸汽爆破预处理的苦荞麸皮不溶性膳食纤维理化特性及结构研究

Study on physicochemical properties and structure of insoluble dietary fiber from Tartary buckwheat bran pretreated by steam explosion

以苦荞麸皮为原料,引入蒸汽爆破技术对其进行预处理,研究不同强度汽爆预处理苦荞麸皮的水不溶性膳食纤维(insoluble dietary fiber from Tartary buckwheat bran pretreated by steam explosion,SE-IDF)理化特性及结构变化。结果表明,与未汽爆处理相比,SE-IDF的持水力、持油力和膨胀力显著降低(P<0.05),其中在汽爆强度低于1.2 MPa,90 s时下降较慢;而SE-IDF的α-淀粉酶活性抑制能力、葡萄糖吸收能力和体外发酵能力显著提高(P<0.05),且随汽爆强度的增加呈先增强后减弱的趋势,整体在1.2 MPa,90 s条件时达到最优;在该汽爆条件下,差示扫描量热分析表明SE-IDF峰值温度提高了9.26℃,热稳定性增强;傅里叶红外光谱显示SE-IDF羟基等官能团位置发生了小范围红移,推测纤维素、半纤维素和木质素成分可能发生部分降解;扫描电镜观察显示SE-IDF表面明显破裂疏松,尺寸减小,相对表面积增大。表明汽爆处理可以改善苦荞麸皮水不溶性膳食纤维的理化特性和结构,且较优条件为1.2 MPa,90 s,可为苦荞麸皮水不溶性膳食纤维的开发利用及保健食品的开发提供理论参考。

The steam explosion technology was introduced to pretreat the Tartary buckwheat bran,and the physicochemical properties and structural changes of insoluble dietary fiber pretreated with different steam explosion intensity(SE-IDF)were studied.The results showed that the water holding capacity,oil holding capacity and swelling capacity of SE-IDF were significantly lower than those of the non-explosion treatment(P<0.05),and the decrease was slower when the explosion strength was lower than 1.2 MPa and 90 s.However,the inhibition capacity ofα-amylase activity,glucose absorption capacity and in vitro fermentation capacity of SE-IDF were significantly increased(P<0.05).And with the increase of steam explosion intensity,it showed a trend of increasing first and then decreasing,and the optimum condition was found at 1.2 MPa and 90 s.Under this condition,thermodynamic parameters suggested that the peak temperature of SE-IDF was increased by 9.26℃,and the thermal stability was enhanced.Infrared spectrum showed that the position of hydroxyl group and other functional groups of SE-IDF had a small red shift,which suggested that the cellulose,hemicellulose and lignin components might be partially degraded.Furthermore,the SEM observation showed that the surface of SE-IDF was obviously broken and loose,the particle size was decreased and the relative surface area was increased.Therefore,steam explosion could effectively improve the physicochemical properties and structure of Tartary buckwheat bran IDF under the optimal condition of 1.2 MPa and 90 s.This study provided a theoretical reference for the development and utilization of Tartary buckwheat bran IDF and the development of health food.