The Drying Characteristic Of Chinese Chestnut And Its Effects On Quality Of Dry Products

The drying was an important unit operation of Chinese chestnut process. The material was Chinese chestnut that was especial production in china. The character of drying, structure of issue, composition of nutrition were studied by different drying methods, which were fired drying, vacuum drying and microwave drying. Some regularity was found in Chinese chestnut drying.The result showed that the appearance of dehydration character in Chinese chestnut was mainly the descend rate of drying in process of fired drying, vacuum drying and microwave drying. The process of drying was control by the diffusion of inside of Chinese chestnut. The drying dynamics model of fired drying and microwave drying was tally with the Page equation. The drying dynamic model of vacuum drying was tally with the model of monomial spread. The different thickness of section has the same trend by different methods. But the affection has obviously different in rate of drying. The thinner section, the rate of drying was the faster.The electron microscope scanning showed that the different drying methods affect structure of issue and appearance of amylum pellet in Chinese chestnut.The browning degrees of Chinese chestnut have different by different drying methods. The vacuum drying was the best method in three methods. The 60℃ is the best in vacuum drying. For fired drying of section, it was the best parameter of technology that was 80℃ and 0.7cm of section. For waving drying, it reduced browning degree of Chinese chestnut, which was lower power, and thinner of section.The contents of lysine in Chinese chestnut have obviously different by different drying methods. The vacuum drying affects lysine content the same fired drying. They haven't change the content of lysine. But, the microwave drying obviously reduced the lysine content of Chinese chestnut.The content of amylum in Chinese chestnut have obviously different by different methods. The content of amylum by the vacuum drying and fired drying was obviously higher than that of the microwave drying. The content of amylum which it was 0.1cm of section and 70℃ was highest by fired drying. The content of amylum has not different by different power of microwave drying, and the content of amylum in 0.7cm section is better than others.The content of flavones and polysaccharides in Chinese chestnut have different by different methods. The content of flavones by vacuum drying was higher than others. The content of polysaccharides by microwave was distinctlyhigher than others.The density of materials, entrance of temperature and exit of temperature in air were important in many factors, which influenced the process of technology in spray drying. The standard regression model was found, it is about the compose of density of materials, the entrance of temperature and the exit of temperature. The molded indicated that the entrance of temperature obviously affected the rate of power of Chinese chestnut, the next was density of materials, and the last one was the exit of temperature. The best compose of factors in the experiment is 11.58% the density of materials, 121.8°C entrance of temperature and 80.8°C exit of temperature.