Study On The Purification Of Konjac Glucomannan And Its Application In Rice

Konjac resources are rich in our country, but the purity of konjac powder is generally low, nature is instable, more time to dissolve completely, easily polluted by bacteria, with its viscosity decreased in a short time, it is only used in food as addiction. At present, we are all focus on the study of structure, property and general chemical modification of the structure, study on the healthy foods and functional foods are few. So it is important to improve the purity and stability of konjac flour, enlarge shelf life and develop the health food.By using konjac powder as raw material, the research studies ultrasonic wave-microwave joint auxiliary ethanol precipitation purified konjac glucomannan and optimize the conditions, purify the konjac flour, prepare the liquid, further test its stability to acid and alkali and the function of falling blood as well as sterilization processing at the same time and study its shelf-life and its application in rice. The following results:(1) Purify konjac glucomannan by using ultrasonic wave-microwave joint auxiliary ethanol precipitation, make sure the effect of every factor to the purification by single factor experiment, choose the influential factors such as liquid ratio,ultrasonic time,ultrasonic power,microwave time. With the purification of konjac glucomannan as the response value, using response surface experiments to optimize the process conditions, get the best process conditions as follows: material liquid ratio 1:100, ultrasonic time 52 min, ultrasonic power 175 W, microwave time 18 s, under this condition, the purity of konjac glucomannan is 97.59%.(2) Choosing liquidity、transparency and viscosity of liquid konjac glucomannan as indictors, easily transported and easily dissolved as principle, we get the best condition when its concentration is 2.5%.(3) By measuring the viscosity change of liquid konjac glucomannan under the different p H conditions, it is concluded that when the p H3~9, the viscosity changed little; when the p H is less than 3 and more than 11, the viscosity changed greatly. It is concluded that the liquid konjac glucomannan is stability to acid and alkali when p H3~9.(4) Respectively establish injury animal model of insulin, insulin resistance sugar/lipid metabolic disturbance model and normal animal model and also determinate the animals, blood sugar, glucose tolerance and the serum total cholesterol, triglycerides, insulin levels a month later. The results of insulin damage animal model show that liquid konjac glucama-nnan can relieve diabetes, but as the illness is aggravating, the function reduced; Results of insulin resistance of sugar/lipid metabolic disturbance model show that liquid konjac glucomannan can enhance the animals’ tolerance to sugar and has the effect of hypolipidemic.(5) Choose three factors such as microwave time、microwave power and initial temperature to design experiment. Get the best conditions through the analysis: microwave time 4min, microwave power 360 W, initial time 40℃, under the conditions, liquid konjac glucomannan can achieve aseptic condition.(6) With Origin software fitting liquid konjac glucomannan viscosity changes under different temperature using zero model and 1st model, by comparing the value of R2, 1st model is more accurate; Combine with Arrhenius equation, achieve the relationship between temperature and the change of liquid konjac glucomannan viscosity, fit regression straight line, draw the corresponding parameters, set up shelf-life prediction model and predict the accuracy of evaluation.(7) By Using rice texture parameters and sensory as index, select five factors to do single factor experiment such as soaking rice proportion of water, soaking time, soaking temperature, cooking water proportion and cooking time, the optimum cooking condition as follow: rice water ratio 1:1.2, soaking time 40 min, soaking temperature 20℃, cooking rice water ratio 1:1.2, cooking time 40 min. Under the condition, the texture parameters are best and the sensory score is highest.(8) In terms of studying the effects of different adding ways and different adding quantity of liquid konjac glucomannan to rice quality and structure characteristic, it is concluded that when added as liquid and the adding amount was 8%, texture parameter changed little on the storage process. Under the condition, konjac glucomannan can relieve the speed of rice aging, and the content of resistant starch reached highest, the function to justify blood sugar is the most significant.