Quality Change Of Brown Rice After Boring Pest Infected

In order to explore the quality changes on brown rice,which was infected by Rhyzoperthadominica and Sitophilus oryzae, screen sensitivity index and establish the mathematical modelfor forecasting the quality changes on brown rice. Brown rice was taken as a test material,which were to be infected by Rhyzopertha dominica and Sitophilus oryzae, setting updifferent population density, every10d take1sample. Some index were determined such asgrain weight,the rice paddy rate, white rice yield, color, falling number, fatty acid value,peroxidase （POD） vitality, conductivity, malondialdehyde （MDA）, reducing sugar content,protein content, cooking characteristics and taste evaluation, et al. Meanwhile make thedifference and correlation analysis on the index, population density and violations time, andthen combining with change on the taste evaluation, screen the sensitivity of the index whichinfluce the quality of brown rice by the grey relational grade math analysis method. Then usemultiple regression to set up the mathematical model of the quality change of brown rice.Themain conclusions are as follows:（1） During the process of Rhyzopertha dominica and Sitophilus oryzae infect brown rice,the adult pest like epidermis with high lipid content and the nutritional embryo, which resultin brown rice not have aleurone layer and embryo, even present bumpy and no embryos；different parts of the infected brown rice, the falling number and POD decreased, fatty acidvalues, electrical conductivity, MDA are rise, and the decay of the embryo and endospermparts of decay difference is different.（2）After brown rice was infected by Rhyzopertha dominica and Sitophilus oryzae, as thethe extension of time,grain weight, milled rate, paddy rate, transparency decreased, L^*valueat first rising then to drop, the a^*value in the0d-30d no change, while30d fell rapidly, b^*value in the0d-30d have risen, after30d begin to decline,40d to lowest, then b^*value andrise again, the greater the population density, infringe upon the time to grow more, the greaterthe defense range; And blank sample no change.（3）After brown rice was infected by Rhyzopertha dominica and Sitophilus oryzae, duringa short time infection and population density, storage quality have small changes, but whentime is longer, the population density, falling number, fatty acid values have large changes, solead to the serious influence on storage quality of brown rice, of which100population densityhead/300g after30d sample quality after severe change happened; The quality indexes in the different infection time and different population density showed different differences.Therefore, We must kill pests within20d in order to void the quality brown rice be affected.（4）After brown rice was infected by Rhyzopertha dominica and Sitophilus oryzae, withthe increase of population density and infected time, the rice’s inflation rate and bibulous rateoverall rise, the value of rice water pH and taste evaluation falls, the total score rice havesignificantly reduced after60d,its taste evaluation are less than60points; rice water solidsand rice water iodine value firstly rise then fall, rice glue consistency firstly rise up after risingdown.（5） the mathematical model of brown rice infected by Rhyzopertha dominica has followas: Y=150.26+0.09X_FN-0.86X_FAV-1.20XEC, by Sitophilus oryzae:Y=209.79+0.13XFN-4.21X_EC. Through the validation state clearly the model is feasible.