Maize Drying Quality Index Selection And Evaluation Methods Establishment

In an attempt to establish a scientific and reasonable method of quality evaluation ofmaize drying, the laws of drying maize quality changes by the hot air and vacuum dryingwere studied, and quality characteristics of maize drying index were selected by theprincipal component analysis and linear regression method, the main conclusions weresummarized as follows:Maize drying under vacuum drying showed essentially accelerated, transient phase ofconstant speed and deceleration. At the same drying temperature, the higher the initialmoisture content, the longer drying time to safe water required, and the average drying rateincreased. Different drying methods should be taken to different mathematical equations tofit the model. Page equation model with the experimental data were fitted better, and thismodel would be applied to vacuum drying, and provide the theoretical foundation andtechnical basis for the optimization of the drying program.With the drying temperature increasing, the maize crack rate was increased by hot airand vacuum drying, and the crack rate was beyond50%when the hot air temperature washigher than80℃, while the crack rate of the vacuum drying was below48%, and the crackrate of the natural drying the lowest was8%. Stress cracks first generated on the side of themaize crown, gradually developed into a short crack, and finally developed into a longcrack. It was mainly single split-based when the maize drying time was short, with thedrying time increasing, double cracks and multiple cracks were increased. Crack number ofdevelopment processes from single to double and then multiple. Vertical cracks were themain cracks, rarely appeared the transverse cracks.With the drying temperature increasing, the starch yield decreased. At the samedrying temperature, the starch yield of the vacuum drying was higher than that of hot air.Starch yield was linearly related with bulk density, PSI, germination rate, POD activity andnegative correlation with the crack rate and conductivity. Crack rate, bulk density,conductivity, and starch content were selected through linear regression method.Z=+0.26X₁-0.25X₂+0.26X₄-0.26X₆model would basically reflect the quality of corndrying, and this method using multiple quality indicators could reflect the general qualityof corn drying, and more accurately showed the changes in the drying process of maize. Using the regression method, a regression equation was obtained:Y=-0.021X₆+0.003X₁-0.005X₂+0.018X₄+5.309.With the drying temperature increasing, the crack rate was increased and maizemoisture, test weight, germination rate, skin ratio were reduced. The dry-milling yieldswere positively correlated with moisture, test weight, germination rate, PSI and werenegatively correlated with the crack rate and skin ratio. The crack rate, germination rate,PSI and dry-milling yields were obtained through principal component analysis.F=α₁×Z₁+α₂×Z₂model would reflect the quality of maize drying. And the regressionequation was Y=0.070X₃-0.127X₄+0.018X₅+62.224.