| Apricot of xinjiang has good quality of high solids content,but the phenomenon of poor quality and bad health is quite common in dried apricot production. In order to solve these problems, thin layer drying experiments of apricot in low temperature were carried out on rotation design. The drying characteristic and the drying model of apricot were studied. In this paper the maim aspects were investigated as follows:In the period of second fast growth, the changes of soluble solids and organic acids content were studied in saimaiti and suokeyaleke. The experiments showed that the soluble solids increased gradually with the fruit maturing and the organic acids reduced during the period. The solid-acid ratio increased significantly.Based on the test bed, thin layer drying experiments of apricot in low temperature were carried out on rotation design. The drying characteristic and the drying model of apricot were studied based on temperature, velocity of drying medium and maturity. And three thin lay mathematical drying models were compared to their coefficients of determination. The results indicated that Wang-Singh model could satisfactorily describe the change regulation of moisture ratio during the drying process of apricot. The values of effective diffusion coefficient increased with the temperature in the range of 30-40℃and velocity of 1-2.2m/s,but reduced with soluble solids content increasing. In the test, temperature has no influence on color, velocity has a little influence only on L*, but maturity has notable influence on L*, a* and b*.Dried apricots made by traditional drying, low temperature drying and sun-roasting drying were compared. The results indicated that apricots made by traditional drying had a better color but poor internal organization. This is the result of excessive sulphuring and high drying strength. Compared low temperature drying to sun-roasting drying with low residual sulfur, low temperature drying was better in color and organizational structure. |
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