挤压膨化紫薯粉对小麦面团糊化特性和热机械学特性的影响

Effect of Extruded Purple Sweet Potato Flour on the Pasting and Thermomechanical Properties of Wheat Dough

挤压膨化技术是一种高温、短时的加工方法,可以改变紫薯粉的特性,从而提高复合面团的品质。因此,本实验对紫薯粉进行挤压膨化,对比研究挤压膨化紫薯粉和紫薯生粉对小麦面团水分分布、糊化特性及热机械学特性的影响。结果发现,与紫薯生粉相比,挤压膨化紫薯粉显著缩短了横向弛豫时间T21(P<0.05),表明挤压膨化能够使水分与淀粉或面筋蛋白紧密结合;此外,与小麦粉相比,添加紫薯粉显著降低了面团的峰值黏度、谷值黏度、终点黏度、崩解值和回生值(P<0.05),尤其是挤压膨化紫薯粉。热机械学特性结果表明挤压膨化紫薯粉能够显著提高面团的吸水率、酶解速率和蒸煮稳定性(P<0.05),缩短面团形成时间,降低回生值和峰值扭矩(P<0.05)。挤压膨化紫薯粉的添加不仅可以提高面制品的出品率,也有助于延缓面团的老化,延长保质期。本研究为挤压膨化紫薯粉在面制品中的应用提供了一定的理论依据。

Extrusion cooking is a high-temperature and short-time food processing technology, which can change the characteristics of purple sweet potato flour, thus improving the quality of composite dough with wheat and purple sweet potato flours. Therefore, the effects of adding extruded purple sweet potato flour(EPSP) versus non-extruded purple sweet potato flour(NEPSP) on water distribution, gelatinization and thermomechanical properties of wheat dough were investigated in this study. Results revealed that compared with NEPSP, EPSP significantly reduced the transverse relaxation time T21(P < 0.05), indicating that EPSP could promote tight binding of water to starch or gluten. Moreover, compared with wheat flour, addition of purple sweet potato flour especially EPSP substantially decreased the peak viscosity, trough viscosity, final viscosity, setback value and breakdown value of dough(P < 0.05). The thermomechanical properties demonstrated that EPSP increased the water absorption, enzymatic hydrolysis rate and cooking stability(P < 0.05), and decreased development time, setback value and peak torque(P < 0.05). These results indicated that EPSP addition could not only increase the yield of dough, but also delay the aging of dough and extend the shelf life of the final product. This study provides a theoretical basis for the application of EPSP in wheat products.