68 results about "Starch Branching Enzyme" patented technology

The invention provides a novel starch branching enzyme that is bound to A-type starch granules in wheat, barley, rye or triticale. The enzyme is not substantially associated with B-type starch granules. A cDNA sequence encoding an isoform of the enzyme has been isolated from the wheat cultivar Fielder and deduced amino acid sequence has been determined.

Rice having reduced levels of starch branching enzymes produce grain having a high relative amylose content in the endosperm. The rice grain of this invention can be of a non-shrunken phenotype despite a lesion in the amylopectin synthesis pathway and may be transgenic or nontransgenic.

Cornstarch characteristics can be changed by expressing a non-corn plant starch branching enzyme in a corn plant. In a preferred embodiment, transgenic corn plants containing the barley starch branching enzyme IIa transgene was generated. Some transgenic corn plants produced seeds containing cornstarch with lowered gelatinization temperature and retrogradation rate while others produced seeds containing cornstarch with higher retrogradation rate when compared to non-transgenic corn plants.

The invention discloses a biological modification method for inhibiting starch retrogradation, and belongs to the field of agricultural product processing and biology. The method comprises the steps of dissolving starch into water to obtain 30% (w/v) of starch milk, adjusting the pH to 7.5, adding 300-1,000U/g of starch branching enzyme of dried starch, treating at 50 DEG C for 4-10h to obtain a reaction solution, washing the reaction solution with deionized water, collecting solid and performing vacuum drying to obtain biological modified starch. By adopting the method, starch molecules have smaller branched chains and relatively high branching degree through the modification effect of the starch branching enzyme to hinder the rearrangement of amylopectin in the storage process, so that starch retrogradation can be well inhibited.

The invention relates to the functional food field and in particular relates to resistant malt dextrin and a preparation method thereof. The resistant malt dextrin disclosed by the invention comprises the following components in percentage by mass: 24%-40% of (alpha-1),6-glucosidic bond, 3%-6% of (alpha-1),2-glucosidic bond, 5%-10% of (alpha-1),3-glucosidic bond, and 44%-68% of (alpha-1),4-glucosidic bond. The preparation method of the resistant malt dextrin comprises the following steps: (1), preparing roasted dextrin by roasting starch, and preparing a roasted dextrin aqueous solution; (2), adjusting the pH value of the roasted dextrin aqueous solution to 7.0-8.0, and adding alpha-amylase for carrying out hydrolysis; (3), inactivating the alpha-amylase when the DE (Dextrose Equivalent) value of the roasted dextrin aqueous solution reaches 10-20, and filtering to obtain a hydrolysis intermediate product; and (4), hydrolyzing the hydrolysis intermediate product by starch branching enzyme to prepare the resistant malt dextrin. The resistant malt dextrin disclosed by the invention has an obvious effect in lowering blood sugar, and has obvious advantages in comparison with the similar dietary fiber products.

The invention discloses a modification method for improving slow digestion performance of starch, and belongs to the field of biological modified starch. According to the modification method disclosedby the invention, spindly starch molecules can be converted into a pyknic branch structure of which the structure is more compact by utilizing starch branching enzyme, so that the digestion rate of the starch is slowed down; by controlling a modification substrate, two-stage treatment of carrying out gelatinized starch modification after granular starch modification is adopted, so that the purpose of enhancing a modification effect of the starch branching enzyme is achieved, the content of slow digestion raw starch in modified starch is further increased, the digestion rate of the starch is reduced, and a thought is provided for preparing the slow digestion starch for biological modification.

The invention relates to a method for increasing the amylose content of plants. The invention provides enzymes, namely granule-bound starch synthase I (GBSS i), starch branching enzyme I (SBE I) and/or starch branching enzyme II (SBE II) which are applicable to genetic engineering operation in a starch synthesis path and are capable of remarkably changing starch composition of the plants. The invention also provides a novel method capable of favorably adjusting starch in plants, which comprises the following step of reducing the expression of the enzymes to obtain a series of transgenic plants which are different in amylose and amylopectin contents and proportions. The invention also provides a construct or carrier for adjusting the starch composition of plants.

The invention discloses starch branching enzyme mutants with improved thermal stability, and belongs to the technical field of enzyme engineering. According to the invention, amino acid residues in astarch branching enzyme are mutated into the amino acid residues with opposite charges to endogenous amino acid residues, an electrostatic interaction is formed between the mutant starch branching enzyme and the endogenous amino acid residues with opposite charges nearby, and the starch branching enzyme mutants with improved thermal stability are obtained; compared with a wild-type starch branching enzyme, half-life periods t1/2 (min, 60 DEG C) of the thermal stability of the starch branching enzyme mutants Q231R, Q231K, T339E, T339D, V37E, V37D and I571D obtained by the invention are respectively extended by 40%, 38%, 21%, 26%, 16% and 21% at 60 DEG C, and the half-life periods t1/2 (min, 65 DEG C) are extended by 1.5-2.0 times at 65 DEG C.

The present invention relates to a transformed plant having a reduced endogenous starch branching enzyme (SBE) activity, and having a heterologous glucan branching enzyme (GBE) activity. The invention also relates to starch obtainable from such a plant.

The invention discloses a preparation method of high-performance starch slurry. The preparation method comprises the steps of dispersing starch with the mass concentration of 10-40% into water; stirring and heating to 40-60 DEG C; reacting for 3-8 hours through stirring a starch branching enzyme at the constant temperature of 40-60 DEG C, wherein 30-150U/g starch is added into the starch branching enzyme; and filtering, centrifugally dehydrating and drying to obtain modified high-performance starch slurry with high branching degree. Compared with unmodified starch, the high-performance starch slurry has the advantages that the gelatinization temperature is reduced, the slurry is not frozen at room temperature, the flowability is favorable, and the adhesion to a pulpified yarn is improved to a relatively high extent.

The invention discloses branching enzyme and an application of branching enzyme for preparing resistant dextrin, which belongs to the technical field of bioengineering. According to recombinant escherichia coli provided in the invention, the enzyme activity of starch branching enzyme can reach 2500 U/mL, the optimum pH of the produced starch branching enzyme is 6.5, and the optimum temperature is 40 DEG C, and a half-life period at the temperature of 40 DEG C can reach 200 h. The starch branching enzyme takes starch as a substrate, the concentration of the substrate through high-temperature acidolysis is 200 g/L-300 g/L, when the temperature is 35-45 DEG C, the enzyme addition amount is 1000-1500 U/g, the enzymatic conversion is carried out at a reaction time of 8-12 h to prepare the resistant dextrin, a resistance component can reach 60%, and a base for industrial production of the resistant dextrin is established.

The invention discloses a preparation method of hydroxypropyl starch resistant dextrin, and relates to the technical field of resistant dextrin. According to the method, hydroxypropyl starch is used as a raw material, prepared starch paste has high transparency, high fluidity, weak retrogradation performance, high stability and good freeze-thaw stability, then alpha-amylase is added for hydrolysis, the solubility of glucose is improved, the content of free glucose in the product can be effectively reduced, and the content of the resistant dextrin is increased; then a starch branching enzyme isadded, the digestion resistance of the starch paste is improved, and therefore the content of the resistant dextrin is more effectively increased. The preparation process for preparing the resistantdextrin by using the hydroxypropyl starch is simple, the yield is high, detection is carried out by means of the method which accords with the national food safety standard GB 5009.88-2014, the content of the resistant dextrin reaches 80% or above, the content of free glucose is 10% or below, and the method has industrial production value.

The invention discloses a method for breeding corn with the enhanced content of amylase. The method for breeding corn with the enhanced content of amylase comprises the following steps that: a recombinant carrier which expresses the following interference RNA molecules is introduced into corn, and corn with silenced starch branching enzyme SBEIIb coding genes is obtained, i.e. the corn with the enhanced content of amylase; and one chain sequence of the interference RNA molecules is shown in a sequence 1 in a sequence table, and the other chain sequence is shown in a sequence 2 in the sequence table. An experimental result shows that the content of the amylase in the corn can be enhanced by 15% through the method. In addition, the method can overcome the limitations of a traditional breeding method, can rapidly obtain a target character by a gene engineering technique and can be combined with conventional breeding so as to quicken the breeding of the production variety of high-amylose corn starch.

The invention discloses a method for improving the transparency degree of a starch liquidation product, and belongs to the field of biological modification starch. The molecular structure of a starchliquidation product is changed through adding starch branching enzymes from rhodothermus obamensis, so that a small branch chain and a higher branching degree are realized; the goals of improving thetransparency and the stability are achieved. The method comprises the following steps of dissolving the starch liquidation product into water according to a certain concentration so as to prepare thestarch liquidation product water solution; the starch branching enzymes are added for reaction for a period of time at a certain temperature so as to improve the transparency of the starch liquidationproduct in the storage process; a novel idea is provided for improving the stability of the starch liquidation product; great potentials and application prospects are realized.

The invention discloses a method for improving freeze-thaw stability of maltodextrin and belongs to the technical field of maltodextrin. The method disclosed in the invention comprises the following steps: introducing starch branching enzymes derived from Rhodothermus obamensis on the basis of the traditional enzymic method for producing maltodextrin, cutting off alpha-1,4-glucosidic bonds, and linking the cut short chains onto a receptor chain so as to form alpha-1,6-branching points, so that the branching degree is increased, more clustered structures are formed, and the aim of enhancing thefreeze-thaw stability of maltodextrin is achieved. The method specifically comprises the steps: size mixing, spray liquefaction, starch branching enzyme interaction, filtering, discoloring, performing ion exchange, concentrating, performing spray drying and the like, thereby obtaining the maltodextrin with excellent freeze-thaw stability.

The invention relates to a method of adjusting a content of plant amylose and amylopectin. The invention provides an enzyme which is suitable for genetic engineering operation and can substantially change starch composition in the plant, wherein the enzyme is granule-bound starch synthase I (GBSS I), starch branching enzyme I (SBE I) and/or starch branching enzyme II (SBE II). The invention further provides a novel method of well adjusting starch composition in the plant, and the method comprises reducing expression of the enzyme, and thus obtaining a series of transgene plants with different content ratios of amylose and amylopectin The invention further provides a constructor or a carrier for adjusting starch composition in the plant.

The invention belongs to the technical field of preparation of starch-beta-cyclodextrin microspheres, and provides a method for preparing starch-beta-cyclodextrin microspheres based on reversed-phaselatex method. The preparation method comprises the following steps: step 1, starch pretreatment: firstly, uniformly dispersing starch into a softening and moistening solution for 1-2 hours of immersion, then centrifuging and drying, then adding 25-35U/g of starch branching enzyme, then reacting for 1-2 hours at 55-65 DEG C, and finally washing with water, centrifuging and drying, so as to obtain afinished product. According to the prepared novel jasmine essence sustained release agent-starch-beta-cyclodextrin microspheres prepared using the reversed-phase latex method, the starch and the beta-cyclodextrin are both taken as the main materials to prepare the sustained-release agent, and the advantages of the starch and the beta-cyclodextrin are achieved at the same time, adsorption sites onthe surface of the microspheres are increased, essence adsorption capacity is increased, and the sustained-release effect is optimized.