小米挤压粉与小米生粉理化性质及营养品质的差异比较

Difference of Physicochemical Properties and Nutritional Quality between Raw and Extruded Foxtail Millet Flour

为了全面分析挤压膨化处理对小米粉品质特征的影响,本文系统比较了小米挤压粉与小米生粉理化性质及营养品质的差异,结果发现:小米挤压粉的密度极显著低于小米生粉(P<0.01),而粒径(P<0.01)和静止角(P<0.01)极显著高于小米生粉。挤压膨化后,小米挤压粉亮度(L*)减小、色泽(a*)变暗、肉眼可观察到色泽的差异。挤压膨化过程中产生较多阈值较低,风味贡献较大的醛类、呋喃类和吡嗪类挥发性风味物质,使得小米挤压粉的风味明显优于小米生粉。醛类,尤其是己醛(其相对质量分数高达34.58%),是小米挤压粉的主要风味贡献物质。与小米生粉相比,小米挤压粉的干基脂肪含量和直链淀粉含量分别减少28.92%和28.21%,但多不饱和脂肪酸含量增加21.08%,其中亚油酸增加19.92%、亚麻酸增加63.40%。据此推测,适量添加小米挤压粉将有利于增强小米制品的风味、改善成品口感、提高成品质量。

To investigate the effect of extrusion on the quality characteristics of foxtail millet flour,the differences of physicochemical properties and nutritional quality between raw and extruded foxtail millet flours were investigated systematically in the present study.The results showed that,the density of extruded flour(P<0.01)was extremly significantly lower than that of raw flour,while the particle size(P<0.01)and angle of repose(P<0.01)were extremly significantly higher than that of raw flour.The brightness(L*)of extruded foxtail millet flour decreased,and the color(a*)became darker and there was an obvious difference in color difference in color observed by the naked eye.Many low-threshold and high-contribution to flavor compounds,such as aldehydes,furans and pyrazines were produced during extrusion,which resulted in the flavor of extruded flour was better than that of raw flour.Aldehydes,especially hexanal(relative content was 34.58%)were the main flavor contributors of extruded foxtail millet flour.Compared with raw flour,the dry basis fat and amylose contents of extruded flour decreased by 28.92%and 28.21%,respectively.But the contents of polyunsaturated fatty acids increased by 21.08%,of which linoleic acid increased by 19.92%and linolenic acid increased by 63.40%.These results suggested that addation of extruded foxtail millet flour would enhance the flavor and taste,improve the texture and nutrition of foxtail millet-derived products.