Study On Antioxidant Effect And Hot-Air Drying Condition Of Collichthys Niveatus

This thesis use Collichthys niveatus as raw material to build a mathematical model for the hot-air drying, research the effect of hot-air drying on fatty acid composition of Collichthys Niveatus. Then the effect of drying condition on Lipid oxidation was analyzed and the optimum drying process was obtained on the basis of Peroxide value, Acid value and TBARS value. Finally fat oxidation inhibition technology was studied. The main contents of this research are as follows:(1) Thin layer hot-air drying of Collichthys niveatus was investigated. The relationship of moisture ratio with drying time and temperature were analyzed. There is a correlation between moisture ratio and drying time or temperature. It points out that temperature is more significant than the drying time. The result shows that the model of Page is the most suitable model. That is MR=exp[-exp(-442.761+2.6917T-0.004113281294T2+0.0006893v)×t1.2051].It is proved to be effective.(2)The effect of hot-air drying time and temperature on the change of the fatty acid composition of Collichthys Niveatus was evaluated. Results show that higher temperature and longer drying time would decrease the quantity of polyunsaturated fatty acids. When the samples dry at72centigrade after9hours, the content of polyunsaturated fatty acids decline obviously, especially Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA), which fell by16.16%and8.68%. In the selected temperature range of the test,40centigrade and56centigrade can keep the nutritional value of Collichthys Niveatus woll.(3)The effect of drying condition on Lipid oxidation of Collichthys niveatus was analyzed. The results show that higher temperature can accelerate fat from oxidative rancidity. Peroxide value (POV), Acid value (AV) and Thiobarbituric acid (TBARS) value will change with temperature. However, POV has the drastic change. Wind speed also have certain influence to lipid oxidation. POV and TBARS value will change with wind speed and POV change more severe. But AV is basically unchanged. According to the results, determination of POV was better than AV and TBARS value during different hot-air drying processing, so choose POV is more easyily to control fat oxidation and ensure product quality. Results show that the optimum drying process are40centigrade temperature,2.5m/s wind speed and9hours drying time.(4) Fat oxidation inhibition technology was studied. Tert-Butylhydroquinone (TBHQ) and D-Isoascorbic acid Na salt are selected to be antioxidant. It is concluded that TBHQ can inhibit fat oxidation significantly and its antioxidation effects is superior to D-Isoascorbic acid Na salt. Citric acid and Vitamin c are selected to be synergist. The citric acid had synergistic effect, while Vitamin c don’t have. The complex antioxidant (TBHQ and D-Isoascorbic acid Na salt) is not better than TBHQ in antioxidation effect. The optimal number value of antioxidant are0.02%TBHQ+0.015%citric acid (synergist)...