| The konjac is perennial herb, belongs to the Araceae.It is mainly distributed in some countries and regions of the tropical and subtropical Asia and Africa.Asian countries cultivated it more generally.Konjac’s nutrition is very rich in starch containing35%,3%protein, as well as a variety of vitamins and minerals of potassium, phosphorus, selenium and other elements.And besides, the content of mannan reaches to45%or more.it also has low-calorie, low-fat and high-fiber characteristics.Although the konjac industry started late in China, the konjac industry has great development prospects. As people know the value of konjac, there is a growing number of scientists and technicians research konjac.According to the statistics of the konjac Association of the Horticultural Society, The konjac flour worldwide production in2007is about19,000tons.China produces about12,000tons, accounting for63.2%of the total production.China has become the largest country of konjac flour production in the world.But after the collection of konjac, it has high moisture content.In addition, the areas of Sichuan and Chongqing has humid climate, it is not suitable for long-term storage.So it is often moldy because of it can not be timely dried.So we eat a small amount of fresh, most of them must dried in short term.The traditional dried in the sun drying methods can not meet the growing scale production and the rapid development of export trade.so research konjac mechanized drying, is of great significance to improve drying speed, ensure the quality of drying and reduce the rotten loss.In this paper, a more comprehensive system of konjac flaky of thermostatic hot air drying temperature and drying experimental research, obtained the following conclusions:through a comprehensive test method, through analyzing experimental data,(1) Temperature relative to the thickness and velocity, greater influence on Konjac patches of water loss rate of konjac flaky; temperature drying curves, control the temperature of50℃(120min)---70℃drying time was more than70℃(120min)---50℃drying time is short, but the thickness has some influence on the drying time.(2) Based on the test data analysis, found the drying characteristic curve of Page model can well describe the konjac flaky of constant and variable temperature, significant regression is very high, the measured values and the values of the error is very small, very high fitting degree. Proved to be reasonable Page model as the mathematical model of konjak slice drying.(3) In the constant temperature drying conditions, compared with the BP neural network and Page model, BP neural network model is not only includes temperature, wind velocity, thickness, time of four parameters, and the fitting precision is better than the Page model, BP neural network is the best mathematical model under isothermal conditions of konjak dry.(4) According to the comprehensive score of hot-air drying conditions, find out the factor level and effect of the combined optimal, temperature, wind speed, thickness, according to the comprehensive score results, the temperature50---70℃, wind speed0.75m/s, thickness5mm as the best experimental combinations.(5) Moisture sorption isotherms of konjac flaky show, konjac effect of temperature on the equilibrium moisture content is not too big, therefore, main factors determining the storage properties of konjac flaky is relative temperature air.(6) Peleg model of konjac flaky wet isotherm fitting effect than the other models, the average relative error of moisture absorption model is5.66%... |
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