128 results about "Tetrasaccharide" patented technology

The invention provides infant formula milk powder for improving intestinal inflammation and / or microbial disorder as well as a preparation method and application of the infant formula milk powder. The invention provides infant formula milk powder for the first time, the infant formula milk powder comprises 2 '-fucosyllactose and lactose-N-neotetraose, and the mass ratio of the 2'-fucosyllactose to the lactose-N-neotetraose is (1-5.5): 1. The infant formula milk powder can improve intestinal inflammation and / or microbial disorder.

The invention relates to the technical field of biology, in particular to a beta-1, 4-galactosyl transferase mutant and a method for biologically synthesizing lactose-N-neotetraose by using the beta-1, 4-galactosyl transferase mutant. The invention discloses a protein, which is a protein HpgalT-186 or a protein HpgalT-146-186, a protein HpgalT-146 and a protein HpgalT-146. The protein HpgalT-186 is a protein obtained by mutating an amino acid residue at the 186th site of a wild type HpgalT; the protein HpgalT-146-186 is a protein obtained by carrying out mutation on an amino acid residue at the 186 site and an amino acid residue at the 146 site of wild type HpgalT. On the basis, a series of escherichia coli is constructed and optimized, the yield of the LNnT synthesized through shake flask fermentation of the finally obtained strain reaches 1.73-4.1 g / L, the highest yield in a 5L fermentation tank reaches 20-45.2 g / L, and efficient synthesis of the LNnT is achieved.

The invention provides a food composition and application thereof in promoting development of intestinal tract glycocalyx layers. The food composition comprises protein, fat, carbohydrate and dietary fiber, and further comprises lactose-N-neotetraose and 3 '-sialic acid lactose, and the ratio of the lactose-N-neotetraose to the 3'-sialic acid lactose is (1: 1)-(3: 1) by weight. In the food composition disclosed by the invention, the lactose-N-neotetraose and the 3 '-sialic acid lactose can be used for up-regulating the transcriptional level of genes, such as has1, has2 and has3, related to the development of the intestinal glycocalyx and the transcriptional level of ext2, so that the development of the intestinal glycocalyx is synergistically promoted.

The invention discloses a molecular modification design method for improving the catalytic activity and the thermal stability of citrobacter vinegaticus-derived hyaluronidase and expression application of the citrobacter vinegaticus-derived hyaluronidase. The interaction of citrobacter vinegaticus hyaluronidase active pocket amino acid residues and hyaluronate tetrasaccharide molecules is visually explored through Pymol, conservative analysis of pocket amino acid evolution is carried out through Consurf, and rational design is carried out through policies of FoldX for calculating enzyme-substrate binding free energy, so that the hyaluronidase catalytic activity is improved. A mutant with significantly improved enzyme activity is obtained through screening, and the thermal stability of the enzyme is further improved through PROSS design and an analysis strategy of mutation site amino acid evolution conservative property and position. According to the invention, the sequence, structure and function of hyaluronidase are deeply studied, and hyaluronidase is mutated from two aspects of stabilizing a catalytic structure and promoting a catalytic reaction, so that a high-activity enzyme with higher application value in industrial production is obtained.

The present invention relates to a combination of a mixture of galactooligosaccharides (GOS) and human milk oligosaccharides (HMO), or a nutritional composition comprising such a combination. The combination or composition is useful for the treatment and / or prevention of stress and / or mood disorders in infants, toddlers and / or children. The mixture of HMO consists of or consists essentially of 2 '-fucosyllactose (2' FL) and difucosyllactose (DFL) or lactose-N-tetrasaccharide (LNT) and 6 '-sialyllactose (6' SL). The invention also relates to the use of a combination of a mixture of galactooligosaccharides (GOS) and human milk oligosaccharides (HMO) or a composition comprising such a combination for the treatment and / or prevention of stress and / or mood disorders in infants, toddlers and / or children, wherein the mixture of HMO consists of or consists essentially of 2 '-fucosyllactose (2' FL) and difucosyllactose (DFL) or lactose-N-tetrasaccharide (LNT) and 6 '-sialyllactose (6' SL).

The invention belongs to the technical field of nutritious food, and discloses a composition for simulating whole breast milk oligosaccharide and application of the composition. In the composition for simulating the whole breast milk oligosaccharide, the mass ratio of 2 '-fucosyllactose to lactose-N-neotetraose to 3'-sialyllactose is (3.9-8.1): (0.8-1.2): (0.8-1.2), and the breast milk oligosaccharide 2 '-fucosyllactose, the lactose-N-neotetraose and the 3'-sialyllactose are mutually matched to take effect in a synergistic manner, so that the whole breast milk oligosaccharide is obtained. The composition can improve the memory ability and cognitive ability of an eating object, can be added into infant food (including infant formula powder, complementary food and nutritional supplements) and nutritional supplements or food of children over 3 years old, teenagers and aged people, and has a wide application prospect.

The invention relates to ulva polysaccharide lyase JpPL40A and application thereof, and belongs to the technical field of functional enzymes, the amino acid sequence of the ulva polysaccharide lyase JpPL40A is as shown in SEQ ID NO.1, and the coding gene of the ulva polysaccharide lyase JpPL40A is as shown in SEQ ID NO.2 or SEQ ID NO.3. The invention further discloses a preparation method of the ulva polysaccharide lyase JpPL40A. The ulva polysaccharide lyase JpPL40A disclosed by the invention can be used for hydrolyzing ulva to obtain unsaturated ulva disaccharide, tetrasaccharide, hexasaccharide and / or octasaccharide.

The invention relates to recombinant escherichia coli and a method for synthesizing sialic acid lactose-N-tetrasaccharide c, and belongs to the technical field of microbial metabolism engineering. According to the research, engineering escherichia coli BAZ for producing LNTri II is taken as an initial strain, two key glycosyl transferases, namely beta 1, 4-galactosyl transferase and alpha 2, 6-sialyltransferase, and three CMP-Neu5Ac pathway enzymes, namely NeuC, NeuB and NeuA, are introduced, and related competitive genes are knocked out; under the conditions of shake-flask culture and fed batch culture, the LST c yield of 1.718 g / L and the LST c yield of 9.745 g / L are achieved through the engineering bacterium respectively, and the huge potential of a microbial cell factory in the aspect of efficient production of complex breast milk oligosaccharides is shown.

The invention relates to ulva polysaccharide lyase PcPL40A and application thereof, and belongs to the technical field of functional enzymes, the amino acid sequence of the ulva polysaccharide lyase PcPL40A is as shown in SEQ ID NO.1, and the coding gene of the ulva polysaccharide lyase PcPL40A is as shown in SEQ ID NO.2 or SEQ ID NO.3. The invention further discloses a preparation method of the ulva polysaccharide lyase PcPL40A. The ulva polysaccharide lyase PcPL40A disclosed by the invention can be used for hydrolyzing ulva to obtain unsaturated ulva disaccharide, tetrasaccharide, hexasaccharide and / or octasaccharide.

A method and application of Escherichia coli BL21star (DE3) BLBRTXST3 and its fermentation method for producing high-purity lactose-N-neotetraose, the invention relates to the technical field of human milk oligosaccharide production, Escherichia coli )BL21 star (DE3) BLBRTXST3 is deposited in the General Microbiology Center of China Microorganism Culture Collection Committee, with the deposit number CGMCC No. 32521 and the deposit date November 6, 2024. The address of the deposit institution is No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing; Escherichia coli ( Escherichia coli )BL21 star (DE3) BLBRTXST3 is used in the fermentation production of lactose-N-neotetraose (LNnT). The present invention improves the yield of lactose-N-neotetraose, uses a chromatographic simulated moving bed to produce high-purity lactose-N-neotetraose with a purity greater than 94%, replaces the traditional solvent crystallization method, has simple separation and purification, is conducive to industrial production, and simultaneously produces linear lactose-N-neohexaose with a purity greater than 95%.

The invention provides a genetically engineered bacterium for producing lactose-N-neotetraose as well as a construction method and application of the genetically engineered bacterium. The genetically engineered bacterium meets the following conditions: (1) exogenous expression of an MFS transport protein, beta-1, 3-N-acetylglucosamine transferase and beta-1, 4-galactosyl transferase is carried out; and (2) over-expression of a galactoside osmose enzyme and a UDP-galactose-4-epimerase is carried out. According to the genetically engineered bacterium disclosed by the invention, the MFS transporter, the beta-1, 3-N-acetylglucosamine transferase and the beta-1, 4-galactosyl transferase are exogenously introduced, and the expression quantity of galactosidase and UDP-galactose-4-epimerase in a genome is enhanced, so that the residual quantity of LNT II in an LNnT synthesis route can be effectively reduced, and the fermentation yield of the LNnT is increased.

The invention discloses a preparation method of chitosan oligosaccharide. The method comprises the following steps: adding chitin into concentrated hydrochloric acid, grinding until the chitin is dissolved into paste, washing with distilled water, and collecting to obtain a white colloidal substance, namely colloidal chitin; dissolving colloidal chitin in a phosphoric acid-citric acid buffer solution to obtain a mixed dissolved solution; adding a crude enzyme solution of composite chitinase into the mixed dissolving solution, placing the mixed dissolving solution in a shaking table for reaction, terminating the reaction in a boiling water bath, centrifuging, and carrying out activated carbon separation, low-temperature rotary evaporation concentration and freeze drying on supernate to obtain a chitosan oligosaccharide finished product. According to the method, chitinase crude enzyme liquid prepared from bacillus subtilis SH21 and chitinase crude enzyme liquid prepared from penicillium oxalicum K10 are used as compound enzymes, chitin is subjected to enzymolysis to prepare the chitosan oligosaccharide, the polymerization degree of the prepared chitosan oligosaccharide is 3-10, trisaccharide, tetrasaccharide, pentasaccharide and hexasaccharide are mainly used, and compared with single enzyme use, the compound enzymes are high in product yield and high in chitin degradation rate.

The invention belongs to the technical field of genetic engineering, and discloses a safe recombinant bacillus subtilis for synthesizing lactoyl-N-neotetraose and a construction method and application thereof, and the recombinant bacillus subtilis is obtained by converting a recombinant bacillus subtilis containing beta-1, 3-N-acetyl glucosamino transferase, beta-1, 3-N-acetyl glucosamino transferase, beta-1, 3-N-acetyl glucosamino transferase and beta-1, 3-N-acetyl glucosamino transferase in bacillus subtilis 168. The recombinant plasmid is obtained by plasmids of a 1, 4-galactosyl transferase gene and a lactose permease gene. The invention provides an engineering bacterium for producing lactyl-N-neotetraose and an application of the engineering bacterium to meet the demand of the market on lactyl-N-neotetraose aiming at the huge demand of the market on lactyl-N-neotetraose and insecurity of lactyl-N-neotetraose produced by most of the existing engineering bacteria in the prior art.

The present disclosure relates to a composition for balancing the immune system of a neonatal or infant subject, the composition comprising an effective amount of 2 '-fucosyllactose, 3-fucosyllactose, 3'-sialyllactose, 6 '-sialyllactose, and lactose-N-tetrasaccharide.

The preparation method comprises the following steps: (1) dissolving agar in a citric acid monohydrate solution, and carrying out acidolysis to obtain an acidolysis solution; centrifuging, filtering, adding beta-agarase AgWH50B, and carrying out enzymolysis for 20-28 hours at the temperature of 30-35 DEG C; boiling, centrifuging and filtering to obtain supernate, namely crude oligosaccharide liquid containing agarotriose; (2) dissolving agar in a phosphoric acid solution, and degrading for 55-65 minutes at the temperature of 97-103 DEG C; centrifuging and filtering to obtain supernate, namely crude oligosaccharide liquid containing agarobiose; (3) dissolving agar in deionized water, adding alpha-agarase A33, and carrying out enzymolysis at 38-42 DEG C for 20-28 hours; and boiling, centrifuging and filtering to obtain supernate, namely crude oligosaccharide liquid containing agarotetraose. The preparation method of the agaro-oligosaccharide is used for preparing agarotriose, agarobiose and agarotetraose, and the product purity is high. The method can provide guidance for subsequent large-scale industrial production of agaro-oligosaccharide.

The invention provides breast milk oligosaccharide for regulating butyric acid and improving intestinal microenvironment health and application thereof. Specifically, the invention provides an application of breast milk oligosaccharide in preparation of food for improving intestinal microenvironment health, and the breast milk oligosaccharide is one of fucosyl oligosaccharide, sialic acid oligosaccharide or lactose-N-tetrasaccharide. Wherein the improvement of the intestinal microenvironment health comprises the steps of regulating and controlling the production of butyric acid in an intestinal system, increasing the overall production of short-chain fatty acid, being utilized by intestinal flora as prebiotics in the intestinal system and producing gas, reducing the production of isobutyric acid and isovaleric acid and / or reducing the pH value to maintain the intestinal microenvironment health. The breast milk oligosaccharide is used for being added into infant food (including infant formula powder, complementary food and nutritional supplements) and nutritional supplements or food for children, teenagers and adults over 3 years old, and has a wide application prospect.

The invention relates to a construction method and application of recombinant escherichia coli for increasing the yield of lactoyl-N-tetrasaccharide, and belongs to the field of microbial genetic engineering. According to the invention, three genes tauB, nikD and livM screened by using a transcriptome technology are proved to be capable of promoting the generation of LNT and LNTri II. An engineering strain MG-LNT-09 is used as a starting strain, the biosynthesis efficiency of endogenous transporter genes tauB, nikD, livM, LNT and LNTri II derived from Escherichia coli K-12 derivative bacteria MG1655 is remarkably improved through single plasmid overexpression, the yield of the LNT in shake-flask culture is as high as 7.77 g / L, and the yield of the LNTri II is as high as 3.03 g / L. The optimized strain MG3WB of which the tauB gene is integrated to the hlyE site obtains the maximum LNT titer of 40.35 g / L in a 5L bioreactor without using any antibiotics or plasmids, has a good industrial prospect, and lays a foundation for further industrial production and synthesis of other complex breast milk oligosaccharides.

The invention belongs to the technical field of microorganisms, and particularly relates to bacillus sp. SQ8, a method for producing dextranase by using the bacillus sp. SQ8 and application of the bacillus sp. SQ8. The strain is strong in growth adaptability and high in enzyme production efficiency. The dextranase produced by the strain SQ8 can be used for preparing high-polymerization-degree isomaltooligosaccharides, in hydrolysate of the strain SQ8, the ratio of tetrasaccharide is 10.8%, the ratio of pentasaccharide is 19.7%, the ratio of hexasaccharide is 42.1%, the ratio of heptasaccharide is 22.7%, the ratio of high-polymerization-degree isomaltooligosaccharides is 95.3%, and the dextranase produced by the strain SQ8 can be used for preparing high-polymerization-degree isomaltooligosaccharides and has a good application prospect.

The invention provides a fucosylated human milk oligosaccharide (HMO) for use in improving brain development and / or vision development in a subject, wherein: a) the fucosylated HMO is lacto-N-fucopentaose-I (LNFP-I) and the subject is an infant up to 12 months old; and / or b) the fucosylated HMO is A-tetrasaccharide, wherein the subject is an infant, a young child or a child.

The invention discloses a beta 1, 3-galactosyl transferase Pm beta 3GalT-S207H and an application thereof, and belongs to the technical field of functional enzymes. And the amino acid sequence of the beta 1, 3-galactosyl transferase Pm beta 3GalT-S207H is as shown in SEQ ID NO. 3. The invention further discloses the application of the beta 1, 3-galactosyl transferase Pm beta 3GalT-S207H in the preparation of lactose-N-tetrasaccharide. According to the invention, 1, 3-galactosyl transferase Pm beta 3GalT is subjected to mutation modification to obtain a mutant enzyme, and compared with a wild enzyme, the enzyme activity of the mutant enzyme is improved by 157.21% and is obviously improved, and the thermal stability and alkali resistance are also obviously improved. The beta 1, 3-galactosyl transferase Pm beta 3GalT-S207H disclosed by the invention has important theoretical value and application value on the industrial production of LNT (Lipoxystrobin).

The invention belongs to the technical field of organic synthesis, and particularly relates to a synthesis method of a Baliella chensinensis lipopolysaccharide O-antigen and application of the Baliella chensinensis lipopolysaccharide O-antigen in the aspect of immunocompetence. The raw materials such as monosaccharide, disaccharide, trisaccharide, tetrasaccharide and the like for preparing the glycoconjugate vaccine can be efficiently synthesized, and the synthesis selectivity and the synthesis efficiency are improved. According to the invention, unprotected ammonia is selected to construct uronic acid amide, and hydrogenation is successfully carried out through the method to obtain the target molecular trisaccharide. Subsequently, monosaccharide, disaccharide and tetrasaccharide target molecules are constructed. Wherein in the construction process of the tetrasaccharide, a method of combining TEMPO and NaOCl is adopted to oxidize the tetrasaccharide into aldehyde, then Pinnick is adopted to oxidize the aldehyde into carboxylic acid, and a two-step one-pot method is adopted to construct the tetrasaccharide. According to the invention, glycoconjugate is prepared by conjugation with HSA, and the glycoconjugate lays a raw material foundation for research and development of the Babyte's fermentum lipopolysaccharide vaccine.

The invention belongs to the field of food, particularly relates to a nutritional composition and application thereof in improving immune disorder, and more particularly relates to application of the nutritional composition in preparing food for improving filial generation body inflammatory factor level disorder caused by maternal immune activation. The nutritional composition comprises essential active ingredients shown as the following (i) and (ii): (i) a neutral fucosylated breast milk oligosaccharide, (ii) a neutral non-fucosylated breast milk oligosaccharide; wherein the neutral fucosylated breast milk oligosaccharide at least comprises 2 '-fucosylated lactose, and the neutral non-fucosylated breast milk oligosaccharide at least comprises lactose-N-neotetraose; in addition, in the nutritional composition, the mass ratio of the lactose-N-neotetraose to the 2 '-fucosyllactose is 1: (1-8), and the 2'-fucosyllactose and the lactose-N-neotetraose can achieve a synergistic effect to regulate filial generation immunity.

The invention provides a method for identifying a connection position of a glucosidic bond in an oligosaccharide glucosidic bond isomer, and belongs to the technical field of analysis and detection of saccharide isomers. According to the method for identifying the connection position of the glucosidic bond in the oligosaccharide glucosidic bond isomer, oligosaccharide compounds in a to-be-detected sample are separated at the same time on the basis of a derivatization reagent with a structure as shown in a formula I by utilizing a high performance liquid chromatography-tandem mass spectrometry technology; structural specificity diagnosis ions are generated based on an electron collision excitation collision mode of organic matter ions to identify the types of glycosidic bonds of disaccharide, trisaccharide, tetrasaccharide, pentasaccharide, hexasaccharide and heptasaccharide isomers of different glycosidic bonds. The method is high in identification efficiency and accurate in identification, and can meet the requirements of glycogen storage disease diagnosis biomarker research. And the formula I of the # imgabs0 # is shown in the specification.

This invention discloses a high-yield lactyl-3-4 ...5-4-4-4-4-4- N This invention relates to plasmid-free genetically engineered strains of tetrasaccharides and their applications, belonging to the field of microbial genetic engineering. The invention screened strains with higher activity. β -1,3-galactosyltransferase gene PmgalT Computer-aided enzyme function modification was used to achieve a shake-flask yield of 10.05 g / L for the constructed mutant. Subsequently, genome integration was performed... breast Multi-copy integration PmgalT * V27I / V39I / Y147F ‑galE‑galU A plasmid-free strain was constructed, enabling it to grow in shake flasks with lactoyl- N The yield of tetrasaccharides reached 14.4 g / L. Using glucose as the sole carbon source, the highest yield of 68.19 g / L was achieved at 64.5 h; using glycerol as the sole carbon source, the highest yield of 62.88 g / L was achieved at 60.5 h, providing a basis for its industrial production.

The invention belongs to the technical field of biological medicine, and particularly relates to a mycoplasma synoviae culture medium capable of improving strain titer and a preparation method of the mycoplasma synoviae culture medium. The mycoplasma synoviae culture medium comprises a basic culture medium and auxiliary components, the basic culture medium is prepared from HEPES, milk protein hydrolysate, MEM, beef heart extract powder, coenzyme I, 1% phenol red, magnesium sulfate heptahydrate, L-cysteine hydrochloride, lactose-N-tetrasaccharide, disodium clodronate and water; the auxiliary components comprise porcine serum and penicillin. According to the mycoplasma synoviae culture medium obtained by the preparation method, the passage time of the mycoplasma synoviae is shortened, and the strain titer is improved. The inactivated vaccine prepared from the chicken mycoplasma synoviae cultured by the culture medium is good in safety and immunogenicity, can effectively prevent infection of the chicken mycoplasma synoviae, and has a good application prospect.

The present application relates to the technical field of human milk oligosaccharide production, and in particular to a production method of high-purity lacto-N-neotetraose crystal. The production method inoculates the E. coli BL21 star (DE3) BLBRTXST3 strain into a seed liquid culture medium to obtain a seed liquid, then accesses a fermenter in a certain proportion, accurately adjusts the temperature, pH and dissolved oxygen, and adds a final concentration of 0.1 mM IPTG for induction during the product synthesis period, supplements glycerol and lactose in an exponential flow addition mode, inhibits the generation of the by-product lacto-N-neohexaose, significantly improves the yield and purity of lacto-N-neotetraose, and finally obtains a lacto-N-neotetraose crystal product with a purity of ≥98% by combining the optimized crystallization process. The method has the advantages of high yield, high purity, few by-products, controllable process safety, and strong industrialization adaptability.

The present invention relates to a hydrogel product comprising a glycosaminoglycan molecule as a swellable polymer wherein the glycosaminoglycan molecule is covalently cross-linked via a cross-linking portion comprising a spacer group selected from the group consisting of disaccharides, trisugars, tetrasugars, and oligosaccharides.

The invention relates to a beta-carrageenan enzyme mutant AfCarY123A and application thereof, and belongs to the technical field of functional enzymes, and the amino acid sequence of the mutant AfCarY123A is as shown in SEQ ID NO. 1. The invention further provides an enzyme preparation containing the mutant AfCarY123A, a recombinant expression vector containing a gene for coding the mutant AfCarY123A, a recombinant engineering bacterium and application of the recombinant expression vector and the recombinant engineering bacterium. The mutants can be used for degrading kappa-carrageenan into kappa-neocarrageenan tetrasaccharide, kappa-neocarrageenan hexasaccharide, kappa-neocarrageenan octasaccharide, kappa-neocarrageenan decasaccharide and kappa-neocarrageenan dodecasaccharide.

The invention relates to the technical field of cosmetics, in particular to acer truncatum moisturizing pre-makeup cream and a preparation method thereof. The acer truncatum moisturizing makeup pre-cream is prepared from the following components in parts by weight: acer truncatum seed oil, cosmetic-grade purified water, cetyl PEG / PPG-10 / 1 polydimethylsiloxane, polydimethylsiloxane, isononyl isononanoate, synthetic wax, microcrystalline wax, glycerol, 1, 2, 4-trimethyl-1, 3-pentanediol monoisobutyrate, propylene glycol monobutyl ether, propylene glycol monobutyl ether, propylene glycol monobutyl ether, propylene glycol monobutyl ether, propylene glycol monobutyl ether, propylene glycol the mannuronic acid tetrasaccharide micro-capsule is coated with 1, 3-propylene glycol / caprylyl glycol / ethylhexylglycerin, butanediol, sodium chloride, a sodium hyaluronate cross-linked polymer and temperature-sensitive polyglycerol-10 stearate. The acer truncatum seed oil containing 6% of nervonic acid serves as core lipid, temperature-sensitive type microencapsulated mannuronic acid tetrasaccharide and response type composite microcapsules are compounded, a'instant moisturizing-delayed moisturizing-barrier repairing 'triple synergistic system is constructed, the defects of a traditional technology are overcome, and the requirements of consumers for long-acting, efficient and mild pre-makeup care are met.

The invention relates to the technical field of microorganisms, and particularly discloses a marine bacterium Bacillus sp.SQ3 and a method for producing dextranase and application thereof, the strain is preserved in China General Microbiological Culture Collection Center (CGMCC) on January 20, 2025, the preservation number is CGMCC No.33458, the preservation unit address is No.3, Yard 1, Beichen West Road, Chaoyang District, Beijing, and the preservation number is CGMCC No.33458. Chinese Academy of Sciences Institute of Microbiology. The dextranase produced by the strain SQ3 has the advantage of preparing high-polymerization-degree isomaltooligosaccharides, in hydrolysate of the dextranase, the ratio of tetrasaccharide is 9.9%, the ratio of pentasaccharide is 15.5%, the ratio of hexasaccharide is 32.7%, the ratio of heptasaccharide is 33.9%, the total ratio reaches 92%, and the strain and the enzyme produced by the strain have the remarkable advantage of being applied to preparing the high-polymerization-degree oligosaccharides.