Production Of Fructooligosaccharides By Immobilized Fructosyltransferase

Fructooligosaccharides(Fructooligosaccharides,FOS)is a kind of important functional oligosaccharides,with the proliferation of bifidobacterium,detoxification,clearing intestinal tract,enhance human immunity and improve lipid metabolism(reduce blood fat and cholesterol)and other physiological effects.has been favored by consumers.The human consumption of fructose,not by intestinal digestive enzyme digestion and absorption,can reach the small intestine by using intestinal bifidobacteria,produced metabolites beneficial to human body,such as short chain fatty acid,acetic acid,butyric acid,thereby regulating the human intestinal pH,inhibit harmful bacteria,bidirectional regulation on human intestinal microflora.At the same time,low fructose intake does not affect the body's blood sugar levels,heat is relatively low,and avoid obesity.As a prebiotic,low-poly fructose can be used in different food formulations.The mature process for the production of FOS is achieved by fermentation of the fructose transferase.In this paper,the immobilized fructosyltransferase production of FOS is studied,including free fructosyl transferase fermentation enzyme preparation,immobilized enzyme fructosyl transfer vector used in the preparation of immobilized fructosyltransferase selection and optimization of process parameters,many aspects of immobilized fructosyl transferase the enzyme reaction characteristics and excellent application in FOS production process.Based on the principle of adsorption and cross-linking,Aspergillus niger,which can produce the enzyme,was selected as the fermentation strain.After culture,a large number of mycelia were obtained.The purified enzyme was obtained by breaking the mill.Then,chitosan was added as the carrier,immobilized reagents,glutaraldehyde and calcium chloride solution,crosslinked 8-16 h,washed,dried and shaped,and finally mature immobilized fructose transferase was obtained.Using batch reaction method,adding 5%immobilized fructose transferase to the sucrose solution of 50%-55%in the reaction tank,controlling the reaction pH 5.0-7.0,the temperature 48-55 °C,and reacting 8-16 h,the qualified FOS product can be obtained.At the end of the reaction,the reaction solution is separated by standard sieve,and the immobilized enzyme can be used for the next batch of material production.The enzyme fermentation process optimization:fructosyltransferase fermentation with Aspergillus niger strains,the best carbon source of fermentation medium for sugar,the best nitrogen source was soybean powder and corn syrup.The optimum fermentation conditions were inoculum size 5%,fermentation time 18h,fermentation temperature 30 °C,fermentation pH 6.0,liquid loading volume 12%,and rotational speed 150 r/min.The optimized immobilization conditions were as follows:the amount of enzyme 160 U/mL,adsorption crosslinked pH 7.0,adsorption crosslinking temperature 30 ?,adsorption crosslinking time 8 h,glutaraldehyde 0.06%(v/v),calcium chloride concentration 0.05%,stirring speed 100 r/min.The optimum conditions of FOS production were as follows:the enzyme content of the immobilized enzyme 5%,the substrate concentration 56%(w/v),the reaction temperature 55 °C,pH 6.0,the reaction time 12 h.