Damaged Grain Categories And Quality Evaluation After Boring Pest In Wheat Grain

Sitophilus zeamais Motschulsky, Sitophilus oryzae （Linnaeus） and Rhyzoperthadominica （Fabricius） are three main kinds of boring pests in stored grain. In order to studydamaged grain categories of the wheat infected by three boring pests, thus some quantity ofmixed wheat stored in Henan province for three years were taken as a test sample, whichwere to be infected fastly by each kind of borers of different densities for different periods oftime under suitable temperature and humidity conditions. Determine the different parts of thedecay and decay the extent of damage as the standard of damaged grain categories, test andmeasure the quality indicator changes, further study crude starch content changes and thecharacteristics gelatinization property of whole wheat flou、the evolution of the–SH and–S-S-content and the secondary structure in the gluten protein, and finds out the correlationthreshold, the result shows:（1） As the lesser grain borers’ population increases and the infection time prolongs,theimpurity rate and insect damage increased,they fastly increased on40d; there is no differentof infected part by Sitophilus oryzae （linnaeus） and Sitophilus zeamais Motschulsky in earlierstage, the number of embryo part is much better than the endosperm part in later stage; thenumber of embryo part is much higher than the endosperm part by infected by Fabricius inlater stage,but there shows contrary result in60d.（2） The boring pests infect and change the path of moisture content in wheat,thedifferent speed of moisture content in the different infected part is no distinction,there is nosignificant difference（P<0.05） of different part infected by Rhyzopertha dominica （Fabricius）and Sitophilus zeamais Motschulsky in different storge time, there is significant difference （P<0.05） of different part infected by zeamais Motschulsky in different storge time;the value ofthousand seed weight、crude protein、water absorption of gluten、Sedimentation value、fallingnumber and gluten index、MDA is on different, the value of dry and wet gluten、gluten indexand POD has change rule,that can be as different decay positions index（3） The moisture content of Categories declined with extent of infection declined,thedecline of Sitophilus oryzae （linnaeus） and Sitophilus zeamais Motschulsky is better thanRhyzopertha dominica （Fabricius）;there is a linear correlation degree of decay with thousandseed weight of wheat infected by Rhyzopertha dominica （Fabricius）, there is Logarithmic relationship of decay with thousand seed weight of wheat infected by Sitophilus oryzae（linnaeus） and Sitophilus zeamais Motschulsky; crude protein、gluten index、falling numberand POD are decline; when the extent of infection is50%～75%,dry and wet gluten、waterabsorption of gluten are decline; Sedimentation value and MDA are increrse.（4） As the lesser grain borers’ population increases and the infection time prolongs,Crude starch content is fluctuation down trend,The decrease of Sitophilus oryzae （linnaeus） isbetter than Sitophilus zeamais Motschulsky and Rhyzopertha dominica （Fabricius）;gelatinization temperature is no change rule, and the coefficient of variation is great; peakviscosity、holding viscosity and final viscosity declined,their coefficient of variation aregetting greater; Sitophilus oryzae （linnaeus） has better effect for breakdown and setback thatare decline,but Sitophilus zeamais Motschulsky and Rhyzopertha dominica （Fabricius） haveno effect for breakdown and setback.（5） As the infection time prolongs,-SH contents in gluten protein increased, their peakvalue are5.58μmol·g^-1、5.48μmol·g^-1and5.73μmol·g^-1at60d; their peak value minimumvalue are5.58μmol·g^-1、7.03μmol·g^-1and7.51μmol·g^-1.Influence for the order are Sitophilusoryzae （linnaeus）,Sitophilus zeamais Motschulsky and Rhyzopertha dominica （Fabricius）;Though the secondary structure of gluten protein has a trace changes, in error range,there isno effect of the secondary structure of gluten protein of wheat infected by the there mainboring pests.