The Influence Of The Thin Layer Drying Of The Potato Quality

Nowadays, potato is an important food and crop in China and at the same time its demand of quantity is very large. Because of the short time of dormancy, the effects of surrounding environment and other elements, potato is easy to become putrid, moldy,shrinking, frostbitten and droopy after harvest, also fresh potato has high demand for surrounding environment. Too low temperature is easily cause frostbite while too high temperature is easy to make potato droopy. The humidity demand is also high, because too high or too low humidity, potato will mildew or shrink. which plays an important role in dehydrated food manufacturing and food processing is used widely in crop and vegetable preservation. To a great extent, drying controls the quality of final products. It is applied to all kinds of products from grain to finished products,raw materials to final products. Thin layer drying is an effective preservation method to decrease loss and control microbe and insects after harvest potato. However, drying is widely used in dehydrating vegetables and fruits, not massively devoting to the research of potato drying.We should ensure potato preserved easily and its good quality.⑴This paper will emphasize the influence of potato quality from thin layer drying. The drying machine is the thin layer dryer which is made up of fan, control cabinet and drying table. Different temperature, wind speed and the size of drying particles are three main elements which affect the total starch content, free starch content.⑵First of all according to GB5009.9-2008, this paper measured full starch in the above three main elements. In the process, then using the water in the temperature of 65.5 and preheating with the water in the temperature of 60, measure the free starch in above three main elements according to the international standard GB5009.9-2008.⑶At last the process measured reducing sugar under the same circumstances with electrochemical method. Different temperature, wind speed and the size of drying particles are three main elements which affect the total starch content, free starch content and reducing sugar. Use these data to determine the quality of processed potatoes after drying.Experimental results show that measured at different temperatures and dried potato samples was 50 ℃, 60 ℃, 70 ℃, 80 ℃, 90 ℃, the different wind speeds of 0.5m / s, 1.0m / s, 1.5m / s, 2.5m / s, 3.5m / s, different particle sizes of 10 mm × 10 mm × 5mm, 10 mm × 10 mm × 10 mm, 10 mm × 10 mm × 15 mm full starch, consisting of starches, sugar. The results show that at a temperature of 70 ℃, wind speed of 1.0m / s, a particle size in the processing quality 10 mm × 10 mm × 10 mm potato is the most appropriate. Full-starch, free starch, reducing sugar content of 80.43%, 18.93%, 0.1288%. So in the process of drying the thin layer of potato processing quality is still influential, and can ensure that the content of intact starch, and the impact of reducing sugar is non-linear, so the nutritional value of potatoes preserved. After drying to control mildew, frostbite, and so some of the damage can be stored for long periods, they did not lose their nutritional value.