Studies On Biochemical Characteristics Of Cassava Starch And Sugarcane Xylan

Glucan(with six-carbon, e.g. starch) and xylan(with five-carbon), the most important carbohydrate for bioenergy, are the material basis for survival and closely related to production and living of human beings on earth. With the development of science and technology, the applications of glucan and xylan should be extended to higher level by detecting. Cassava starch and sugar cane xylan were chosen as testing material and their properties were studied.Amylose and amylopectin were prepared by recrystallization with n-butanol and homemade cassava starch. Their qualitative and quantitative measurement was observed by color reaction of starch-iodine reaction. There are significant differences in this testing. Purified amylose and amylopectin were enzyme hydrolyzed by extracted wheat starch enzyme. Moreover, the content values of 75%.96% and 66% for original starch, amylose and amylopectin were obtained by measuring the contents of reductive sugar.As seen from the values, the content of amylopectin is lower than other starch. Therefore, one can state that the content of starch was inversely proportional to the extent of branch, which can affect many of physical and chemical properties and provide the further classification and detection of each component of starch.The content of amylose in original starch was determined in the sample of mixed purified amylose and amylopectin at diffirent proportions. A standard curve of absorbtion values, y = 1.0128x + 0.0462(R~2 = 0.9994). was obtained at 620nm. As the standard curve, the quality of amylose is 0.181, which was agree with the one of amylose in cassava starch.Xylan, an amorphous polymer, the external shape of which was different in varied batch. Therefore, it can be screened by the methods of particle size screen, water sub-phase of natural sedimentation and sub-dissolution at different temperatures. The movement viscosity properties of xylan and glucan is contrast, which of xylan has a liner relationship with its concentration and is more lower than the one of original starch or amylose in the same concentration where the movement viscosity of tapioca was rising rapidly.The highest conversion rate of reducing sugar, the best condition of xylan(1mg) was hydrolyzed in acid, is obtained in the constant temperature water bath of 100℃and time 60min and the concentration of HC1 was 1M and 50mL was used.As the digestive test, the wheat starch enzyme would not digest any xylan.A strain of hydrolisis xylan was screened in the sewage of the sisal hemp factory. The best condition of enzymolysis xylan in producing protease culture medium as follows: the optimal centrifuge condition of preparation is rotation speed 6000r/min for 15min, temperature 60℃, pH value 6.0 and time 30min. As the result, the unitary enzyme can not degrade the xylan completely, the working together of more enzyme is needed. Amylose and amylopectin would be digested by the bacteria solution, especially for the amylose, whereas the stachyose was unaffected.