Protein,Lipid And The Quality Change Rule Of Insect Damaged Wheat

Invisible infection after wheat harvest is serious,the major boring pests particularly important,such as maize weevil,Sitophilus zeamais Motschulsky,rice weevil,Sitophilus oryzae(Linnaeus).In this paper,we study the index of quality,protein,lipid and edible character while the boring pests developing in the wheat kernel.The results prove that:(1)When the moisture content of wheat is 13%,the inoculation conditions of maize weevil is 29.77?,73.79RH%,8000 one/kg,the inoculation conditions of rice weevil is 28.77 ?,78RH%,7844.76 one/kg,when the infection rate reach 85%.The average development period of maize weevil is 28.66 d,the average development period of rice weevil is 30.86 d.Under the condtion of 28± 1?,75±5%RH,the sampling time of maize weevil is 5d(egg stage),19d(Larval stage),26d(pupal stage),the sampling time of rice weevil is 6d(egg stage),21d(Larval stage),8d(pupal stage).Get samples of adult stage after adults no longer climb out.(2)The moisture content of the control sample keep balance after reach moisture equilibrium,while the moisture content of sample in four developmental stages increased at first and then decreased after the adult drilled.Compared with the control sample,the ash content,hardness index,falling numbe,thousand seed weight,volume weight of the sample all decreased.Flour yield lower than the control sample and the adult stage have a rebounded.The falling numbe tended to increase.50%sucrose,5%lactic acid,5%sodium carbonate,water SRC(solvent retention capacity)low in the egg stage compared to the adult stage,and than increased along with the growing of the pest.(3)The corrode of the Rice weevil and maize weevil led the structure of the wheat kernel serious changed,wheat gluten was broken,disulfide bond was damaged and cannot be formed,part of the gluten unable to form a smooth dough,and into flocculent.wheat gluten injury by the Rice weevil is relatively poor than the maize weevil.Microstructure of the wheat gluten have thorny material,and increase with growth of the pest.The network structure most uneven in the pupal stage,Gluten hole inside is more and more rough.Gluten water holding capacity have no significant difference compared with the control sample.compared with the control sample,the content of the albumin,globulin,gliadin rose,while the gluten content decreased.The content of the GMP rose along with growing of the pests,and reached the highest in pupal stage adult period,decline after the adult the drilled.The content of the-SH,S-S decline.The content of the ?-helix,?-Angle is lower than the control sample,rise after the adult the drilled.The content of the ?-fold,random curl is higher than the control sample,decline after the adult the drilled.Along with growing of the pests,The amino acid of the wheat kernel change in different degree,most of the amino acid content appeared inflection point in pupal stage.The essential amino acid content is highest in the pupal stage,and decline in the adult stage.(4)Rice weevil and maize weevil causes the decay of the fat content,and there is a slight rebound in the pupal stage.Fat continuous oxidation,fatty acid value increased.The excretion of the pest,such as uric acid and other substances result the increase of water-soluble acid value.fatty acid composition of the wheat change in different degrees,part of the fatty acid composition had different changes on the basis of different pest species.(5)Compare with the control sampel,flour yield is low,and rebound when adult drilled.There is a different degree of fission of the rheological behavior of the whole wheat flour,texture propertiestaste of the steamed bread and the evaluated value of the steamed bread.(5)The otherness of the indexes of the wheat are different.Part of the indexes have significant differences in Each developmental stage(6)The quality change of the steamed bread determine by the protein,fatty,excretion and body of the pests.The change of the proportion of each protein will have an effect on the quality of the steamed bread.The boring pest damaged the glutin structure,and become more serious along with the growing of the pest.The boring pest led the degeneration of the lipid,crude fat content decline and fatty acid value rose,features of the protein can't express,and accelerate the quality fission of the steamed bread.