| Oats have the advantages of high protein and high dietary fiber,and their status in the diet is increasing day by day.However,due to the high lipase activity of oats,the fat oxidation will lead to rancidity and affect the shelf life.At the same time,the surface of oats contains more microbial,which will cause the oats to deteriorate.Therefore,this thesis used oats as research materials to study the effects of stir-frying heat treatment,low-temperature plasma,and gas chlorine dioxide on the physicochemical properties,and microbial of oats.The results of the study were as follows:(1)The effect of different stir-frying time on the physicochemical properties and shelf life of oat flour was studied.The results showed that compared with the control oat flour,stir-frying heat treatment(10 min,20 min,30 min)could significantly increase the extraction rate of oat flour.The lipase activity,the peak viscosity,final viscosity,enthalpy value,and crystallinity of stir-frying oat flour showed a decreasing trend,indicating that the gelatinization degree of oat flour increased.Stir-frying reduced the weight average molecular weight of ?-glucan in oat flour and increased the distribution range of ?-glucan molecular weight.During the accelerated storage period,the fatty acid value of the oat flour for different frying time(10 min,20 min,30 min)showed an upward trend during the storage period,and the fatty acid value of the control oatmeal changed faster.According to the Arrhenius kinetic model and statistical principles,it was predicted that the stir-frying oat flour for 30 min had the longer shelf life,and the shelf life at room temperature(25?)was 229 days.(2)The effect of low-temperature plasma treat(LTPT)on the physicochemical properties of oat grains microbial and oat flour was studied,and the results showed that low-temperature plasma treatment(5 min,10 min,15 min,20 min)could significantly reduce the number of microbial,but treatment for too long would inhibit seed germination,the germination rate of oat grains treated for 20 min was the lowest.The microstructure of the seed coat showd that low-temperature plasma could destroy the surface of the cortex and cracks appear.Low-temperature plasma treatment increased the L*value,water holding capacity and expansion force of oat flour.The characteristics of oat flour showed that low-temperature plasma treatment changed the gelatinization properties of oat flour,and reduced the peak viscosity,retrogradation value,indicating that the aging of oat flour was inhibited to a certain extent.The X-crystal diffraction and Fourier infrared results of oat flour showed that low-temperature plasma treatment had no effect on the crystal structure of oat starch and the secondary structure of protein.(3)The effect of gas chlorine dioxide on oat grains microbial and physicochemical properties was studied.The results showed that the gas chlorine dioxide treatment concentration of 0.25 mol/L,0.47 mol/L,and 0.69 mol/L had a significant inactivation effect on oat grains microbial.The microstructure showed that in the high-concentration treatment group,cracks appeared on the surface of oat starch,indicating that the gaseous chlorine dioxide oxidized the starch to a certain extent.Gas chlorine dioxide treatment could increase the solubility of oat starch.Gelatinization characteristics and thermodynamic results showed that gas chlorine dioxide reduced the viscosity and enthalpy value of starch,indicating that the starch after gaseous chlorine dioxide oxidation had stronger hydration and gelatinization ability.The gas chlorine dioxide oxidation treatment reduced the DD value and DO value of oat starch.The effects of three treatments on the physicochemical properties and microbial of oats showed that 30 minutes of stir-frying could extend the shelf life of oat flour and improve the properties of the dough;low-temperature plasma and gas chlorine dioxide technology could be used as new technologies to inactivate oat grains microbial is in pretreatment. |
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