低温挤出-多酶协同降解脱胚玉米中淀粉的机理

    Mechanism of starch degradation of corn grist degermed by extruded at low-temperature and multienzyme synergistic degradation

    • 摘要: 为了改变目前挤出酶解谷物淀粉仅添加一种酶制剂(α-淀粉酶),只能降解淀粉的α-1,4糖苷键,不能降解支链淀粉的α-1,6糖苷键,限制淀粉转化成葡萄糖的收率进一步提高的现状,该文应用低温(≤80 ℃)挤出-多酶(α-淀粉酶、糖化酶、普鲁兰酶)协同降解技术,制备挤出过程中物料的石蜡显微制片,观察脱胚玉米经低温挤出-多酶协同降解处理后,细胞壁、细胞中的淀粉颗粒和蛋白质颗粒的分布状况以及淀粉含量、糊化度、可溶性糖含量的变化。结果表明:在挤出过程中,淀粉发生糊化和降解,表观淀粉质量分数减少,从81.50%减少到74.40%,可溶性糖质量分数增加,从1.07%增加到2.26%,挤出过程中加入酶制剂后这种变化更加明显。添加单一α-淀粉酶表观淀粉质量分数从79.72%减少到69.16%,可溶性糖质量分数从6.54%增加到7.90%。添加α-淀粉酶和糖化酶表观淀粉质量分数从81.42%减少到72.45%,可溶性糖质量分数从11.65%增加到14.71%。添加α-淀粉酶和普鲁兰酶表观淀粉质量分数从81.31%减少到70.31%,可溶性糖质量分数从6.74%增加到8.29%。添加α-淀粉酶、糖化酶、普鲁兰酶3种酶时淀粉质量分数从81.06%减少到69.05%,可溶性糖质量分数从11.25%增加到16.35%。因此,3种酶(α-淀粉酶、糖化酶、普鲁兰酶)协同作用对淀粉降解以及可溶性糖含量的增加作用效果最好。显微切片的分析结果表明:添加3种酶制剂(α-淀粉酶+糖化酶+普鲁兰酶)的切片,细胞结构中淀粉颗粒被降解破坏的程度大于添加1种(耐高温α-淀粉酶)、2种(α-淀粉酶+糖化酶,或者α-淀粉酶+普鲁兰酶)酶制剂的细胞结构中淀粉颗粒被降解破坏的程度。低温挤出-多酶协同降解后,脱胚玉米挤出物的总淀粉含量降低、可溶性糖含量增加,糊化度增加。试验表明:添加3种酶制剂协同降解脱胚玉米中淀粉的作用效果优于添加1种酶制剂或2种酶制剂的淀粉降解效果,为进一步提高淀粉转化成葡萄糖的收率提供科学依据。

       

      Abstract: In order to improve the conversion rate of starch to glucose, an enzyme (α-amylase) was added to amylopectin by changing the α-1,6-glycoside bond in amylopectin by extrusion enzymatic hydrolysis technology, and the microstructure of paraffin section was introduced. Low temperature (≤80 ℃) extrusion, multi-enzyme (α-amylase, glucoamylase, pullulanase) synergistic degumming preparation. The distribution of protein granules and starch granules and the main physicochemical indexes of starch degradation in cells were observed. The results showed that starch content decreased from 81.50% to 74.40% and soluble sugar content increased from 1.07% to 2.26% during extrusion. The change of enzymatic extrusion process was more obvious. By adding α-amylase, starch content decreased from 79.72% to 69.16%, soluble sugar content increased from 6.54% to 7.90%. By adding α-amylase and glucoamylase, the starch content decreased from 81.42% to 72.45%, and the soluble sugar content increased from 11.65% to 14.71%. By adding α-amylase and pullulanase, starch content decreased from 81.31% to 70.31%, soluble sugar content increased from 6.74% to 8.29%. By adding α-amylase, glucoamylase and pullulanase, the starch content decreased from 81.06% to 69.05%, and the soluble sugar content increased from 11.25% to 16.35%. The results of microsection showed that the degradation degree of starch granules in the three enzymes was better than that of one (α-amylase) or two enzymes (α-amylase, glucoamylase or α-amylase, pullulanase). The results showed that starch content decreased, soluble sugar content increased and gelatinization degree increased in degummed maize by low temperature enzymatic extrusion. At the same time, the effect of adding three enzymes (α-amylase, glucoamylase and pullulanase) on starch degradation was better than adding one enzyme (α-amylase) or two enzymes (α-amylase, glucose- amylase or α-amylase, pullulanase). These results provide useful data for improving starch utilization.

       

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