Influence Of Tempering On Quality Characteristics Of Medium Wheat And Microbe Activity

In this study, to explore the influence of tempering time, water addition and temperingtemperature on quality characteristic of medium wheat and microbe activity, fiverepresentative medium wheat materials were selected in the whole country. The indexes toevaluate the properties of milling were flour yield, ash content, protein content, damage starchcontent, falling number, pink color, gluten quality, opaque characteristics and tensileproperties. Meanwhile, the influence of brine tempering on part of quality characteristic ofmedium wheat and microbe activity were explored.The results showed that: the tempering time had a complex influence to wheat qualitycharacteristic, the experimental results were different as wheat varieties. Along with thetempering moisture and temperature increased, the flour yield, ash content and protein contentdecreased with different degree.Tempering moisture had a positive correlation to falling number, pink color, gluten index,gluten moisture absorption, development time, stability time, the value, tensile area, tensileresistance, maximum tensile resistance and tensile rate. And the tempering moisture had anegative correlation to gluten content, water absorption, degree of softening, degree ofextension. As wheat varieties, the indexes had significant, extremely significant or nosignificant correlation to tempering moisture. For most of the medium wheat materials, whenthe tempering moisture exceeds17.5%, the flour quality would decrease.Tempering temperature had a positive correlation to falling number, pink color, glutenindex, development time, stability time, the value, tensile area, tensile resistance, maximumtensile resistance and tensile rate. And the tempering temperature had a negative correlation togluten content, water absorption, degree of softening, degree of extension. As wheat varieties,the indexes had significant, extremely significant or no significant correlation to temperingtemperature.The flour yield, ash content, damage starch content and gluten index increased of allwheat on the condition of brine tempering. And the change of gluten content and glutenmoisture absorption were complex as the wheat material varieties. From1%to5%, with theincreasing of concentration of salt water, the ash content and gluten index increasedsignificantly. And the change of flour yield, damage starch content, gluten content and gluten moisture absorption were complex as the wheat materials varieties.From12h-24h, with the increasing of tempering time, microbe activity increasedsignificantly of all wheat materials. From5℃-35℃, with the increasing of temperingtemperature, microbe activity increased continued, and after35℃the microbial activitydecreased significantly. Along with the increasing of tempering moisture, microbe activityincreased significantly. Brine tempering could reduce the microbe activity terribly. When thetempering time was12h, tempering water was12.5%and tempering temperature was5℃, themicrobe activity was in a minimum level on the surface of medium wheat.