碱提方法对小麦麸皮阿拉伯木聚糖结构及面团特性的影响

Effect of Arabinoxylan Extracted by Different Methods on the Dough Thermo-Mechanical and Rheological Properties

通过采用氢氧化钠和饱和氢氧化钡溶液提取小麦麸皮中的阿拉伯木聚糖,比较所得碱提阿拉伯木聚糖(Alkline extracted arabinoxylans,AEAXs)的得率、纯度、侧链取代度和单糖组成以及相对分子质量之间的差异,探讨不同提取方法对AEAXs结构的影响及不同结构和添加量AEAXs对面团热机械学特性和流变学特性的作用。结果发现,采用氢氧化钠(含0.88%过氧化氢)所制备AEAXs纯度较高,侧链阿拉伯糖基取代度较低,而饱和氢氧化钡所得AEAXs纯度最高,侧链阿拉伯糖基取代度和相对分子质量也较大。面团热机械学特性测定结果表明,所有AEAXs的添加均会显著提高面团吸水率、降低面团回生值,且降低面团形成时间和稳定时间,而采用氢氧化钠(含0.88%过氧化氢)所制备AEAXs其添加对面团稳定时间负面影响最小。当添加量从2%升高至3%时,效果更明显。流变学试验结果发现,3%氢氧化钠(含过氧化氢)所得AEAXs的加入可以增加面团黏性模量G",而其他提取剂所得AEAXs则会降低小麦面团的G’和G"。

This study was aimed to compare the yield rate, purity, substituted ratio of side chain, monosaccha- ride composition and difference of relative molecular mass of alkaline extracted arabinoxylans （AEAXs） extracted from wheat bran by different sodium hydroxide and barium hydroxide solutions, and explore the effect of these AEAXs on the thermo -mechanical and rheological properties of wheat dough. The results showed that AEAXs prepared by sodium hydroxide （containing 0.88% hydrogen peroxide） had higher purity and low substituted ratio of side chain arabinoxylan, while AEAXs prepared by barium hydroxide had high purity and high substituted ratio of side chain arabinoxylan and relative molecular mass. The thermal mechanical properties determination of wheat dough showed that the presence of AEAXs increased water absorption and decreased the dough setback value, which also decreased dough development and stability. And the addition of AEAX extracted by sodium hydroxide （0.88% hydrogen peroxide） produced the least negative effect on dough stability. When the addition was increased from 2% to 3%, a significant effect showed. The rheological re- sults showed that with the addition of AEAXs prepared by 3% sodium hydroxide （0.88% hydrogen peroxide） increased the dough viscosity modulus, while other AEAXs would decrease G＇ and G＂ of wheat dough.