Study On Hot Air Drying And Storage Packaging Method To Quality Changing Of Seedless Grapes

Seedless grapes are characteristic of Xinjiang, loved by million of people. Seedless grapes are the most common way of processing grapes, but there are many problems in the production process, such as poor health conditions, easy browning, long drying time, a significant impact on the quality of products, taste of raisins. In order to solve these problems, this paper illustrates drying characteristics, drying kinetics and storage during hot air drying process of Thompson seedless grape. There is mainly for the following discussion:1. After air drying the physicochemical index of Seedless grapes was analyzed, the dry end of raisins was moisture content below 15 %; the total acid content in 0.9 %-1.1 %; the content of ascorbic acid in 1.90-2.05 mg/100 G-DW, total phenolic content between 0.04-0.06 mg/g- DW; browning degree between 0.3-0.45 A420, and in the dry in the process of Thompson seedless grape, grape, ascorbic acid in titratable acid, total phenol content decreased, and the degree of browning increased2. Through study on the drying characteristics of hot air drying of seedless grape, found that drying Thompson Seedless Grape drying; drying time at the temperature of 45 ℃ under the condition of the shortest, the moisture content is below 15 %, the time required for 104 h, but the temperature of 40 ℃ dried raisins, browning degree minimum, maintain good quality.3. The temperature conditions were 30, 35, 40, 45 ℃ of seedless grapes for drying, temperature and drying rate, the effective diffusion coefficient showed positive correlation, and the diffusion coefficients were 1.3E-11, 1.6E-11, 2.3E-11, 2.8E-11 m2/s.4. The study on the drying characteristics of seedless grape test showed, respectively the drying process on the 30, 35, 40, 45 ℃ temperature conditions for model fitting, by fitting 6 kinds of drying model, found that the drying process under different temperature conditions are suitable for the two order polynomial Wang-Singh model, according to the Arrhenius formula under the condition of Thompson Seedless Grape hot-air drying drying activation energy of 22.16 kJ/mol.5. We Study under different storage conditions by raisins change the quality of different packaging methods. The raisins 150 days of storage test, the results showed that: in 25 ℃, 11.3 % and 35 ℃, 75.3 % of the two storage conditions, the best quality, raisins and nitrogen vacuum packaging packaging.