小麦制粉过程前、中、后路粉品质及流变学特性差异分析

Analysis of the difference in quality and rheological properties of front,middle and rear road flour in wheat flour making process

出于对成本的考虑,目前国内外淀粉、谷朊粉一般利用后路粉进行生产,虽然后路粉制备的淀粉、谷朊粉产量高,但是质量较差。基于这种现状,利用粉质仪、拉伸仪及流变仪对3种小麦粉的前、中、后路粉的品质及流变特性进行了比较分析,探究各路粉之间存在的具体差异性。研究表明:各小麦粉由前路到后路,其灰分、蛋白质含量、干湿面筋含量、降落数值、糊化温度、吸水率、延伸度均逐渐升高;白度、面筋指数、峰值黏度、最低黏度、衰减值、最终黏度、回生值、峰值时间、拉伸阻力、最大拉伸阻力逐渐下降,均存在明显的差异性和规律性;后路粉面团形成时间长于前路粉,稳定时间、弱化度、粉质指数的变化没有一致的规律性;损伤淀粉、水溶物含量均呈先降低再升高的趋势,后路粉面团产气能力高、发酵稳定性高、持气性不佳,中路粉面团膨胀度最高、持气性最佳。对于后期具有针对性的系统粉配粉,工业生产小麦淀粉和谷朊粉品质的提高及原料面粉的选用提供了理论指导。

At present,starch and gluten protein is usually produced by rear road flour at home and abroad for the consideration of cost,although the yield is high,the quality is poor. Based on this status quo,this study compared and analyzed the quality and rheological properties of front,middle,and rear road flour in wheat flour making process by using farinograph,extensometer and rheometer,so as to explore the specific differences among the three basic powders. Among them,the farinograph can reflect the kneading resistance of the dough,and intuitively reflect the stability time and weakening degree of the dough. It can be used to evaluate the gluten strength of dough and determine the quality and application of wheat flour. The extensometer can directly reflect the stretching resistance and elongation of the dough. Therefore,it can be used to evaluate the elasticity of the dough and the strength of the protein in the dough. The rotary rheometer can provide the viscoelastic properties of the polymer network with different oscillation frequencies. Therefore,it can be used to reflect the elasticity and viscosity of dough and gluten. The rapid viscosity analyzer is an effective tool for analyzing the α-amylase activity and starch gelatinization characteristics of cereals and their products. It is beneficial for the industry to select specific flour mill streams mixing,so as to improve the quality of rear road flour. Previous studies have reported that ash content,protein content,dry gluten,wet gluten,falling value,gelatinization temperature,water absorption,and elongation of rear road flour in almost every wheat are higher than the front road flour. The whiteness,gluten index,peak viscosity,minimum viscosity,attenuation value,final viscosity,retrogradation value,peak time,stretching resistance,and maximum stretching resistance gradually decrease from the front to the rear flour,all of which showed obvious differences and regularities. The formation time of rear road flour dough is higher than that of front road flour,and there is no uniform regularity in the change of stability time,weakening degree and flour quality index. The content of damaged starch and water-soluble matter both decreased first and then increased. The rear road flour dough has high gas production capacity,high fermentation stability,and poor air retention. The middle flour dough has the highest expansion and the best air retention.Conclusion: There are same regular changes in the physicochemical properties of front,middle,and rear road flour during the same process of different wheat flour milling and rheological changes of the formed dough except for the stabilization time,weakening degree,and flour quality index. This study not only provides a reference for the system powder blending in the later stage,but also provides a theoretical guidance for improving the quality of starch and gluten protein produced by industry and the selection of raw flour.