An enzymatically produced soluble -glucan fiber composition is provided suitable for use as a digestion resistant fiber in food and feed applications. The soluble -glucan fiber composition can be blended with one or more additional food ingredients to produce fiber-containing compositions. Methods for the production and use of compositions comprising the soluble -glucan fiber are also provided.

Method for the production of dextran comprising the following steps: prepare a culture medium containing the appropriated mixture and balance of ingredients, mainly after accurate selection of nature and concentration of carbon and nitrogen sources, with a specific initial pH, inoculate the culture medium with an appropriated quantity of bacteria strain (to standardize the production and avoid as much as possible the variability of the system); carry out the fermentation for a given time and at a given temperature; precipitate the dextran to separate the product from the culture medium; the bacteria strain is a strain of Weissella cibaria.

Method for the production of dextran comprising the following steps: prepare a culture medium containing the appropriated mixture and balance of ingredients, mainly after accurate selection of nature and concentration of carbon and nitrogen sources, with a specific initial pH, inoculate the culture medium with an appropriated quantity of bacteria strain (to standardize the production and avoid as much as possible the variability of the system); carry out the fermentation for a given time and at a given temperature; precipitate the dextran to separate the product from the culture medium; the bacteria strain is a strain of Weissella cibaria.

Compositions are disclosed herein comprising a graft copolymer that comprises: (i) a backbone comprising dextran that has been modified with about 1%-25% alpha-1,2 branches, and (ii) one or more alpha-1,3-glucan side chains comprising at least about 50% alpha-1,3 glycosidic linkages. Further disclosed are reactions for producing such graft copolymers, as well as their use in derivatives, films and various other applications.

Compositions are disclosed herein comprising a graft copolymer that comprises: (i) a backbone comprising dextran that has been modified with about 1%-25% alpha-1,2 branches, and (ii) one or more alpha-1,3-glucan side chains comprising at least about 50% alpha-1,3 glycosidic linkages. Further disclosed are reactions for producing such graft copolymers, as well as their use in derivatives, films and various other applications.

A production method of low molecular weight ?-glucan includes: inoculating an activated Leuconostoc mesenteroides in a 5 L fermentor at a 10% inoculum. Fermentation broth is placed in the fermentor at an initial pH of 6.8-7.0, temperature of 25? C. to 28? C., stirring speed at 120 r/min, and fermented for 20-40 hours. Dextranase is added after 5-30 hours of fermentation at a dosage of 1/10,000 to 5/10,000 by volume. The molecular weight of ?-glucan is controlled within 10000D by the amount of enzyme added, and the total fermentation process is about 20-40 hours. After the reaction is terminated, the fermentation liquid is concentrated and dried to prepare dietary fiber products with a molecular weight of 500-5000D. The viscosity of the fermentation liquid and concentration of ?-glucan in the fermentation liquid may be reduced to promote the forward reaction, accelerate the sucrose conversion rate and increase the product yield.

A production method of low molecular weight ?-glucan includes: inoculating an activated Leuconostoc mesenteroides in a 5 L fermentor at a 10% inoculum. Fermentation broth is placed in the fermentor at an initial pH of 6.8-7.0, temperature of 25? C. to 28? C., stirring speed at 120 r/min, and fermented for 20-40 hours. Dextranase is added after 5-30 hours of fermentation at a dosage of 1/10,000 to 5/10,000 by volume. The molecular weight of ?-glucan is controlled within 10000D by the amount of enzyme added, and the total fermentation process is about 20-40 hours. After the reaction is terminated, the fermentation liquid is concentrated and dried to prepare dietary fiber products with a molecular weight of 500-5000D. The viscosity of the fermentation liquid and concentration of ?-glucan in the fermentation liquid may be reduced to promote the forward reaction, accelerate the sucrose conversion rate and increase the product yield.

Reaction compositions are disclosed herein comprising at least water, beta-glucose-1-phosphate (beta-G1P), an acceptor molecule, and an alpha-1,3-glucan phosphorylase enzyme. These reactions can synthesize oligosaccharides and polysaccharides with alpha-1,3 glycosidic linkages. Further disclosed are alpha-1,3-glucan phosphorylase enzymes and methods of use thereof.

Reaction compositions are disclosed herein comprising at least water, beta-glucose-1-phosphate (beta-G1P), an acceptor molecule, and an alpha-1,3-glucan phosphorylase enzyme. These reactions can synthesize oligosaccharides and polysaccharides with alpha-1,3 glycosidic linkages. Further disclosed are alpha-1,3-glucan phosphorylase enzymes and methods of use thereof.

An enzymatically produced soluble -glucan fiber composition is provided suitable for use as a digestion resistant fiber in food and feed applications. The soluble -glucan fiber composition can be blended with one or more additional food ingredients to produce fiber-containing compositions. Methods for the production and use of compositions comprising the soluble -glucan fiber are also provided.