穗发芽小麦面团流变学特性动态研究初探

为研究穗发芽对小麦面团流变学特性的动态影响,对大田生产条件下的轻度穗发芽和正常的小麦品种龙麦26进行了面团不同醒发时间的拉伸仪(45、90、135min)和吹泡示功仪(28、45、90、135min)等全面的品质分析。结果表明:当小麦穗发芽程度较轻时,无法通过面粉蛋白、干面筋、湿面筋含量、面筋指数、沉降值、粉质参数和吹泡参数这些品质指标的数值大小来判断被测样品是否为穗发芽小麦或穗发芽的程度。拉伸数据表明穗发芽龙麦26面团最大拉伸阻力在90min时最高,变化趋势为先增加后减少,各阶段的最大阻力均明显低于一般年份龙麦26应有的数值。而正常龙麦26面团最大拉伸阻力在135min时最高,变化趋势为随着时间的增加逐渐变高,且各阶段的阻力明显高于穗发芽龙麦26。因此在没有测试降落值条件的情况下,可以通过拉伸参数及动态趋势来推测样品可能为穗发芽小麦及穗发芽程度。吹泡数据与拉伸数据的意义有很大差别。穗发芽和正常龙麦26面团的P值和W值变化趋势都是随着时间的增加逐渐变低。28min时穗发芽龙麦26的吹泡数据好于正常龙麦26,但90和135min则相反,原因是穗发芽龙麦26面团的下降程度较大。由此说明不同仪器间的品质指标均有着各自的特殊性,不能相互替代。

Preliminary Study on Dynamic Change of Dough Rheological Properties of Pre-harvest Sprouting Wheat

To study the effect of pre-harvest sprouting on dynamic changes of dough rheological properties,slight pre-harvest sprouting and normal wheat samples of Longmai 26 collected in production condition were employed to determine quality parameters including different proofing times Extensograph parameters(45,90,135 min)and different proofing times Alveograph parameters(28,45,90,135 min).The results showed that,wheat pre-harvest sprout or not as well as degree of sprouting couldn’t be determined by the value of quality parameters like flour protein content,dry and wet gluten,gluten index,sedimentation value,Farinogram parameters and Alveogram parameters,in case of slight sprout.Extensogram data showed the maximum resistance value of the pre-harvest sprouting grain of Longmai 26 was the highest at 90 min,and the dynamic trend was firstly going up and then going down.Compared to the normal Longmai 26,the maximum resistance values of sprouted wheat at each time points were obviously low.While the maximum resistance value of the no sprouting Longmai 26 gradually went high with the time and got the highest at 135 min,and the maximum resistance value of each stage was obviously higher than the pre-harvest sprouting Longmai 26.Therefore,when falling number determining facilities was not available,wheat pre-harvest sprouting and degree could be predicted by obviously decreased Extensogram parameters and their dynamic trends.Alveogram and Extensogram parameters meant difference significantly.P value and W value of Longmai 26 in Alveogram,no matter sprouting or not,were all gradually reduced with the time.At 28 min,the Alveogram data of the pre-harvest sprouting Longmai 26 was better than that of no sprouting,but at 90 and 135 min,the situation was just the reverse.The reason was that the dough quality of sprouted Longmai 26 decreased greatly with the increase of proofing times.The experimental data showed that each quality index from various equipments had special meanings and couldn’t be replaced each other.