Study On Chemical Modification And Moisturization Of Flue-cured Tobacco Polysaccharide

Polysaccharide is one of the important functional compositions from tobacco leaves,which has many biological activities and very wide application and development prospects.Therefore this study is to study the extraction of flue-cured tobacco leaves polysaccharides,the chemical modification of polysaccharides,and moisture retention of polysaccharides.The main research contents and results are as follows:1.In this study,taking flue cured tobacco leaves to extract tobacco leaf polysaccharide by ultrasonic assist,then investigating the effects of four single factors(ultrasonic power,solid-liquid ratio,ultrasonic temperature and ultrasonic time)on the extraction rate of polysaccharide,and using the orthogonal method to optimize the process conditions.The results showed that the optimal technological conditions were as follows: ultrasonic power 400 W,solid-liquid ratio 35:1,ultrasonic temperature 60 ? and the ultrasonic time 10 min.Under these conditions,the extraction rate of polysaccharide was 3.18%.2.Carboxymethyl tobacco polysaccharide was obtained as a product of the tobacco polysaccharide and chloroacetic acid in the sodium hydroxide solution.The effects of three single factors(reaction time,chloroacetic acid concentration and reaction temperature)on the degree of substitution of carboxymethyl polysaccharide were investigated,and the optimum conditions for the modification of polysaccharide were determined by response surface methodology(RSM).The results showed that the optimal conditions for the preparation of carboxymethyl polysaccharide from tobacco leaves were as follows: reaction time 3.8 h,concentration of chloroacetic acid 1.6mol/L and reaction temperature 50?.Under these conditions,the substitution degree of carboxymethyl tobacco polysaccharide was 0.814.3.Acetylated tobacco polysaccharide was obtained as a product of the tobacco polysaccharide and butanedioic anhydride.The effects of three single factors(reaction time,the ratio of polysaccharide to acetic anhydride and the reaction temperature)on the degree of substitution of acetylated polysaccharide were investigated,and the optimum conditions for the modification of polysaccharide were determined by response surface methodology(RSM).The results showed that the optimal conditions for the preparation of acetylated polysaccharide from tobacco leaves were as follows: reaction time 3.1 h,acetic anhydride: polysaccharide(mg:mg)43:1 and reaction temperature 50?.Under these conditions,the substitution degree of acetylated tobacco polysaccharide was 0.425.4.Phosphorylated tobacco polysaccharide was obtained as a product of the tobacco polysaccharide and phosphate.The effects of three single factors(reaction time,reaction temperature and p H value)on the content of polysaccharide phosphate were investigated,and the optimum conditions for the modification of polysaccharide were determined by response surface methodology(RSM).The results showed that the optimal conditions for the preparation of phosphorylated polysaccharide from tobacco leaves were as follows: reaction time 6.1 h,reaction temperature 95? and p H value 9.0.Under these conditions,the phosphate content of phosphorylated polysaccharide was 11.68%.5.Compared with propylene glycol and blank sample,the moisture retention property of four humectants(including tobacco polysaccharide,carboxymethyl tobacco polysaccharide,acetylated tobacco polysaccharide and phosphorylated tobacco polysaccharide)and their effects on maintaining the moisture content in cut tobacco were tested and contrasted.The results showed that the moisture retention capacities of tobacco polysaccharide,carboxymethyl tobacco polysaccharide and phosphorylated tobacco polysaccharide was slightly stronger and the moisture retention of acetylated tobacco polysaccharide was weaker than propylene glycol;the moisture retention of carboxymethyl tobacco polysaccharide was stronger than phosphorylated tobacco polysaccharide and that of tobacco polysaccharide was weaker among them.6.The pyrolysis of tobacco polysaccharide and carboxymethyl tobacco polysaccharide was carried out under the conditions of 300,600 and 900?,and the pyrolysis products were analyzed by gas chromatography mass spectrometry(GC/MS).The results show that there were great differences in the types and contents of the pyrolysis products of polysaccharide at different temperatures,and with the increase of temperature,the types of the pyrolysis products also increased.The products were mainly composed of furans,ketones,aldehydes and phenols.