挤压膨化对金针菇-发芽糙米复配粉的消化特性及挥发性物质的影响

【目的】通过研究金针菇-发芽糙米复配粉的淀粉、蛋白质和挥发性物质在挤压前后的变化,探讨挤压膨化工艺对金针菇-发芽糙米复配粉的消化特性和风味的改善影响,为膨化产品的消化特性及风味分析提供参考。【方法】将金针菇-发芽糙米复配粉原料进行挤压膨化加工,利用扫描电镜、聚丙烯酰胺凝胶电泳、红外光谱以及体外消化等方法对淀粉和蛋白质的颗粒微观结构、蛋白质分子量和二级结构、淀粉和蛋白质的消化率等进行分析,探讨挤压膨化对金针菇-发芽糙米膨化产品消化特性的影响,并通过气相色谱-质谱联用法对风味成分进行对比分析。【结果】金针菇-发芽糙米复配粉原料经挤压膨化后,产品中淀粉颗粒由典型的大米颗粒外貌变为无规则形状,淀粉含量降低8.26%,还原糖和可溶性糖含量分别上升了1.35倍和18.45%,淀粉体外消化率提高30.68%。而金针菇-发芽糙米膨化产品中蛋白质颗粒也由膨化前的棱角圆滑的多面体型变为无规则形状,蛋白质含量降低1.00%,蛋白质体外消化率提高25.57%。金针菇-发芽糙米复配粉挤压膨化前,蛋白质分子量主要分布在50、36、33、22、19和13 kD左右,经过挤压膨化后,蛋白质分子量50 k D左右的谱带消失,而分子量36 k D以下的蛋白质谱带没有明显变化。金针菇-发芽糙米膨化前后及发芽糙米膨化产品蛋白质光谱整体相似,但在1 645 cm~(-1)和1 544 cm~(-1)处的吸收峰强度差别较大。与膨化前物料相比,金针菇-发芽糙米膨化产品中醛类、醇类、吡嗪类分别增加了18.93%、44.17%、77.64%,酮类物质增加了1.56倍。发芽糙米原料中含量较高的醛类和醇类物质经过挤压加工后均呈现降低趋势,而在金针菇-发芽糙米复配粉原料中这些物质经挤压加工后均表现出升高趋势,说明添加金针菇对膨化产品风味有增强作用。【结论】挤压膨化可提高金针菇-发芽糙米膨化产品的消化特性,并且添加金针菇能够丰富和增强膨化产品的风味。

Effect of Extrusion on Digestion Properties and Volatile Compounds in Germinated Brown Rice Compounded of Flammulina velutipes Flour

【Objective】The objective of this study was to investigate the effect of extrusion process on digestion properties and volatile compounds in germinated brown rice compounded of Flammulina velutipes flour through the changes of starch, protein and volatile compounds, thus providing references for the analysis of extrudant digestion properties and flavor.【Method】 In order to study the effects of extrusion on digestion properties and flavor compounds, germinated brown rice compounded of Flammulina velutipes was extruded to investigate the particle microstructure of starch and protein, the protein molecular weight and protein secondary structure, the digestibility of starch and protein, and the volatile compounds using scanning electron microscope, SDS-PAGE electrophoresis, infraredspectroscopy, in vitro digestion method and gas chromatography-mass spectrography.【Result】The results showed that the granule shapes of extruded starch and protein were changed into irregular shape compared with the un-extruded compounded powder. Moreover, the starch content and protein content in germinated brown rice compounded of F. velutipes extrudant decreased by 8.26% and 1.00%, respectively. However, the reduced sugar content, the soluble sugar content, in vitro starch digestibility and in vitro protein digestibility increased by 1.35 times, 18.45%, 30.68% and 25.57%, respectively. The protein molecular weight mainly distributed in 50, 36, 33, 22, 19 and 13 kD in un-extruded compounded powder. However, the 50 kD molecular weight disappeared and the 36 kD molecular weight had no change in germinated brown rice compounded of F. velutipes extrudant. The infraredspectraof protein in extruded were similar to that of un-extruded powder, but the absorption peak intensity had significant difference between 1 645 and 1 544 cm^-1. The contents of aldehydes, alcohols, pyrazines and ketones compounds in germinated brown rice compounded of F. velutipes extrudant were increased by 18.93%, 44.17%, 77.64% and 1.56 times, respectively. The aldehydes and alcohols compounds in extruded products of germinated brown rice showed a decline trend compared with un-extruded germinated brown rice. However, the increasing trend to that of the extruded products of germinated brown rice compounded of F. velutipes was exhibited, indicating the flavor enhancement of F. velutipes.【Conclusion】Extrusion technology could improve the digestion characteristics of germinated brown rice compounded of F. velutipes extrudant. Meanwhile, the mixture of F. velutipes could enhance the flavor of the product.