本研究以燕麦作为发酵基质，采用酶预处理协同红曲霉后发酵技术，探索燕麦多糖含量、组成及生物活性的变化规律。研究表明，采用β-葡萄糖苷酶协同红曲霉发酵可以提高发酵燕麦的多糖含量至4.50%（W/W），是常规发酵组的1.21倍，是未发酵组的2.23倍。采用高效液相色谱测定发现发酵使燕麦多糖分子量增大，发酵前10~100 ku分子量多糖占92.12%，发酵后大于100 ku分子量多糖占83.91%，最高分子量达到2.57×103 ku；发酵后单糖组成发生显著变化，甘露糖和半乳糖比例明显上升，葡萄糖有所降低，鼠李糖没有检测到，单糖组分摩尔比例为甘露糖:葡萄糖:半乳糖:木糖:阿拉伯糖=2.50:6.81:4.14:1.09:2.13。发酵后红曲燕麦多糖的生物活性有所提高，清除羟自由基、ABTS+自由基的能力和抑制淀粉酶的能力均高于未发酵燕麦。研究可为燕麦深加工提供一条新途径。

In this work, the changing trends of the amount, composition and bioactivities of oat polysaccharides were investigated using oat as the fermentation substrate and through the combined use of enzymatic pretreatment and Monascus fermentation technology., Results revealed that the yield of polysaccharides reached to 4.50% (W/W) after β-glucosidase hydrolysis followed by Monascus fermentation, which was 1.21 times as high as that for the conventional fermentation group, and 2.23 times as high as that for the unfermented group. HPLC analysis revealed that the fermentation process led to increased molecular weights: 91.12% for molecules in the range of 10~100 ku before fermentation whilst 83.91% with molecular weights greater than 100 ku after fermentation, with the highest molecular weight up to 2.57×103 ku. The composition of monosaccharides changed significantly after fermentation, the proportions of mannose and galactose significantly increased, whilst the proportion of glucose decreased with rhamnose not detected. After fermentation, the oat polysaccharides were composed of mannose (Man), glucose (Glc), galactose (Gal), xylose (Xyl) and arabinose (Ara), at a molar ratio of 2.50 : 6.81: 4.14 : 1.09 : 2.13, and had improved bioactivities. The polysaccharides from fermented oats exhibited a higher hydroxyl radical scavenging activity, ABTS+ radical scavenging ability and a-amylase inhibitory activity, compared to those from unfermented oats. The results of this research present a new approach for deep processing of oats.

广东省省级科技计划项目（公益研究与能力建设专项）（2017B020207003）；广州市科技计划项目-产学研协同创新重大专项（201604046011）