Study On Processing Technology Of Hot Air And Microwave Puffing Drying Of Chinese Water Chestnut Slices

Chinese water chestnut is well-fed, and is favored by people. Nowadays, the production of Chinese water chestnut is still primary, the technology is relatively lagged, and the fresh Chinese water chestnut is cheaply sold and rotted. Developing Chinese water chestnut production industry can make the product market become big, upgrade the industry, get good society and economy benefits.Hot-air drying was one of the broadly used dehydration method. Hot-air drying characteristic and processing technology was investigated at first. Microwave technology as a newly high technology was developed rapidly in food engineering. In the production of Chinese water chestnut, the combination of hot-air and microwave was not reported inside and outside the county.This paper was emphasis on the processing course, method parameters chosen of hot-air drying and microwave puffing drying, in order to acquire the best processing method. Results showed:1. The critical temperature of hot-air drying of Chinese water chestnut is 65℃, critical time is 110℃-45min,100℃-60min,90℃-75min,80℃-120min,70℃-180min. On the condition of 60 -90℃constant temperature hot-air drying, the Chinese water chestnut slices have good redehydration property, the low the temperature, the better the redehydration property, the redehydration property is the best at 60℃,and the redehydration coefficient is 86.4%2. Using 0.2% citric acid solution as color-protector and subsection temperature-changing drying could prevent products from browning in drying course; in subsection temperature-changing drying, the water chestnuts are dried at 90℃for 75min at the first section, at 65℃for 3h at the second section, then get Chinese water chestnut slices, and it remains the flavor and color and luster of raw materials well.3. Through single factor and orthogonal experiments, the optimal technology parameter for microwave puffing was acquired. With the thickness of Chinese water chestnut slice 3 mm, it is moisture content 35% before puffing, microwave power 475 W, puffing time 14 S.4. Before the Chinese water chestnut was dried, marinated in the liquid of citric acid 0.01%., salt 1%, tomato powder 1%, then could get the slices with both of flavor and mouthfeel.