Preparation And Purification Of Xylo-oligosaccharides From Tobacco Straw

Cellulose substances are closely related to human life and are widely used in energy and food.Cellulose substances mainly include three parts: cellulose,hemicellulose,and lignin.The ratio of the three is about 4:3:3.Xylan is the main substance that constitutes hemicellulose and is abundant and renewable.Cellulose substances in the human body cannot be directly digested and absorbed by the intestine,can increase people’s satiety,and have good moisture retention,can absorb a large amount of water,easily combined with high calorific substances such as fat in the body,Stimulate intestinal peristalsis,play a role in good fat loss and prevent constipation.Xylo-oligosaccharide is a common functional oligosaccharide with remarkable health care function.It can promote the proliferation of beneficial bacteria in the intestine and has good water absorption and moisturizing properties.It is good for gastrointestinal health and laxative,and it also has improved.Immunity,prevention of cancer,stone,lower blood pressure,blood sugar,cholesterol,prevention of dental caries,oral protection,promotion of calcium absorption and other biological effects,sweet,good heat resistance,can be used as a food additive,to meet obese patients and "three The requirements of special groups such as high populations have received extensive attention at home and abroad.The huge yield of tobacco straw in China and the rich content of hemicellulose in the straw can be used as a raw material for the preparation of xylooligosaccharides.This measure has significant economic and ecological benefits.For this purpose,the laboratory has begun research on the preparation of xylo-oligosaccharides from tobacco stalks.The research includes the extraction of xylan and the preparation and purification of xylo-oligosaccharides.The main findings are as follows:1)The pretreatment method of tobacco straw is 60°C water soak 6 h,and then dry standby;2)By using the sulfuric acid and potassium dichromate oxidation method andhydrochloric acid hydrolysis combined with DNS method,the mass fraction of cellulose,hemicellulose,and lignin in the tobacco straw was determined to be 42.72%by the Klason method and the ultraviolet spectrophotometer method.20.17%,22.14%.The optimum conditions for determination of tobacco straw hemicellulose were determined: 80% calcium nitrate volume 8 mL,boiling time 3 min,hydrochloric acid concentration 4 mol/L,boiling water bath time 45 min;3)This study tried to use alkali extraction of xylan from tobacco straw and enzymatic hydrolysis to prepare xylo-oligosaccharides,optimize the extraction conditions of xylan and xylo-oligosaccharides,and extract the xylan conditions: 24%(W/V)NaOH and 1%(W/V)NaBH4 lye,solid to liquid ratio 1:8(W/V),alkaline hydrolysis time 3 h,alkaline hydrolysis temperature 70 ℃,3x ethanol volume The amount of xylan was about 24% when the amount of alcohols and 0.2 times the volume of acetic acid were used for neutralization.The conditions for preparing xylo-oligosaccharides were as follows: 8mL xylan solution(20mg/mL),10 mL xylanase solution(0.6%,4.1U/mL),the solution system pH is 5.50,the enzyme hydrolysis time is 5h,the enzymatic hydrolysis temperature is 40 ℃;4)After elution of xylo-xylose liquid with different volumes of cation resin,considering the total sugar extraction rate and the area of ??the buffer,we conclude that when the desalting is performed with six volumes of cationic resin,the effect is relatively good and the yield is high.Up to 30.32%;When activated carbon is used as the stationary phase for elution,30% ethanol is used as eluent to obtain relatively separated xylose and xylobiose.