75 results about "Pullulanase" patented technology

The invention belongs to the field of food microorganisms, and particularly relates to a saccharomycopsis fibuligera strain, a microbial inoculum, a fermented product and preparation and application thereof. The saccharomycopsis fibuligera strain provided by the invention is preserved in the China Center for Type Culture Collection on September 25, 2023, and the preservation number of the saccharomycopsis fibuligera strain is CCTCC NO: M 20231788. The saccharomycopsis fibuligera strain provided by the invention can produce amylase, protease, cellulase and other enzymes required by fermentation, the amylase has the activity of pullulanase and raw amylase and can well adapt to the special environmental conditions of fermentation, and the saccharomycopsis fibuligera strain has high environmental tolerance and high aroma-producing capacity; therefore, the quality of fermented products is improved, and the fermentation production investment cost is reduced.

The invention discloses radix ophiopogonis powder for relieving anxiety and improving sleep. The radix ophiopogonis powder is prepared by carrying out fermentation on radix ophiopogonis through plant lactobacillus GDMCC No. 64374 and carrying out enzymolysis treatment through pullulanase. The invention further discloses a preparation method and application of the radix ophiopogonis powder. The saponin content of the radix ophiopogonis powder is obviously increased. The radix ophiopogonis powder can be prepared into products in various forms, has the effects of relieving anxiety mood and improving sleep, is high in bioavailability and free of toxic and side effects, and can be eaten for a long time. Compared with the traditional radix ophiopogonis powder, the radix ophiopogonis powder disclosed by the invention is relatively low in safety risk and more obvious in effects of relieving anxiety mood and improving sleep.

The invention belongs to the technical field of starch modification and food processing, and particularly relates to a method for debranching all components of corn starch through heat-assisted continuous ethanol gradient grading. According to the method for debranching all components of corn starch through heat-assisted continuous ethanol gradient grading, firstly, gelatinized corn starch is subjected to debranching treatment through pullulanase, then the debranched starch is graded through continuous ethanol gradient (15%-75%) under the condition of different temperatures (50-100 DEG C), and fractions with specific chain length distribution, crystal structures and functional characteristics are obtained. According to the method disclosed by the invention, the precise separation of each component of the debranched starch is realized through the synergistic effect of regulating and controlling the temperature and the ethanol concentration. According to the method, the problem of component overlapping in a traditional single-proportion ethanol grading method is solved, the influence of heat-assisted continuous ethanol gradient grading on the starch structure and functional characteristics is disclosed, and an innovative method is provided for directional preparation of high-resistance starch and full-component high-value utilization of corn starch.

The present invention relates to a process for purifying phycocyanins from a solution comprising phycocyanins and glycogen, said phycocyanins being produced by microorganisms belonging to the order Cyanidiales, characterized in that it comprises (i) an enzymatic degradation step of glycogen with an enzyme suitable for degrading glycogen at a pH below 6 and a reaction temperature below 40°C, said enzyme being selected from a pectinase, a glucoamylase, or a mixture of a pectinase and a pullulanase, and (ii) a step of separating phycocyanins from the glycogen degradation products.

To provide a new technique capable of improving foam retainability of a foam-retainable fermented malt beverage.SOLUTION: The foam-retentive fermented malt beverage contains an enzyme agent containing at least one kind of enzyme selected from the group consisting of glucoamylase, pullulanase, α - glucosidase and β - amylase, wherein acid protease is inactivated. The amount of saccharides contained in the foam-retentive fermented malt beverage can be 1. 0g / 100ml or less. The NIBEM value of the foam-retentive fermented malt beverage can be 80 or more.SELECTED DRAWING: Figure 1

The invention discloses an application of a composition of neopullulanase and transglucosidase in bread making, the addition amount of the neopullulanase is 500-1000 U / kg of flour, and the addition amount of the transglucosidase is 500-1000 U / kg of flour. The novel pullulanase and the transglucosidase are used for making the bread, and the two cooperative enzymes are used as improvers, so that the specific volume of the bread is increased, and the texture of the bread is more excellent, the chewiness of the bread is kept stable during storage, and the problem that the conventional bread is strenuous to chew after being stored is avoided; meanwhile, the cohesiveness is reduced, the sticky feeling during chewing is reduced, the conglutination level is also remarkably reduced, and the oral eating experience is further optimized; in addition, the hardness of the bread can be remarkably reduced, the bread is kept soft in taste within the storage period, the aging speed of the bread is effectively reduced, and the storage time of the bread is prolonged. The method can effectively improve the bread performance, and can be used as an effective supplement for a traditional bread performance improvement method.

The present application relates to the field of food processing, and particularly relates to a preparation method of quinoa and red date yoghurt. The method comprises the following steps: quinoa is soaked, ground, and treated by gradient temperature enzyme inactivation, and then mixed with red date pulp at a volume ratio of 1:1, and then treated by alpha-amylase liquefaction, saccharifying enzyme and pullulanase compound saccharification, and low-oxygen flavor pre-hybridization, and then mixed with reconstituted milk and compound stabilizer konjac glucomannan and sodium pyrophosphate, and then sterilized, cooled, inoculated with starter culture, and then fermented and ripened to obtain the product. The present application eliminates the peculiar smell of quinoa by gradient enzyme inactivation, and saccharifying enzyme and pullulanase have a significant synergistic effect in the quinoa and red date yoghurt system, and the secondary enzymolysis of liquefaction and saccharification significantly improves the starch utilization rate, and the compounding of konjac glucomannan and sodium pyrophosphate significantly improves the product texture, and the present application solves the technical problems of low starch utilization rate, obvious peculiar smell, poor water holding capacity, and low viable count of traditional quinoa yoghurt.

The invention discloses a preparation method of zein-starch Pickering emulsion loaded with daidzein and relates to the technical field of emulsion preparation, waxy corn starch is subjected to enzymolysis through pullulanase and is applied to emulsion construction, and the emulsion with good stability is researched to realize efficient loading. The invention also discloses a zein-short amylose composite nanoparticle, a preparation method of a Pickering emulsion stabilized by the composite nanoparticle, and the Pickering emulsion stabilized by the composite nanoparticle. The Pickering emulsion with stable composite nanoparticles prepared by the invention has the characteristics of high stability and high safety, and provides a substitute with a good application prospect for the transportation of a bioactive substance daidzein.

This invention discloses a pullulanase mutant with enhanced catalytic activity against highly branched dextrin substrates, its construction method, and its applications, belonging to the fields of enzyme engineering and biotechnology. This invention obtains two mutants, D139A and D139E, by site-directed mutagenesis of the pullulanase derived from Klebsiella pneumoniae at position 139 aspartic acid residue. Compared with the wild-type enzyme, both mutants maintain high hydrolytic activity against pullulan polysaccharides while significantly improving hydrolytic activity against dextrin substrates with high α-1,6 glycosidic bond content. Specifically, the hydrolytic activity against dextrin substrates with 6% and 10% α-1,6 bond content is increased by up to 242% and 110%, respectively. The pullulanase mutants obtained in this invention exhibit excellent catalytic performance in the enzymatic debranching reaction of highly branched dextrin substrates, showing promising application prospects in starch deep processing and related biomanufacturing fields.

The invention provides whole-grain matrix powder of a special dietary food for diabetics and a preparation method of the whole-grain matrix powder, and belongs to the technical field of food processing. Comprising the following steps: adding beans into grains, performing crushing, adding pullulanase and cellulase, performing mixed enzymolysis, after the mixed enzymolysis is completed, adding high-temperature alpha-amylase, performing enzymolysis to obtain standby powder B, performing extrusion puffing, and performing crushing to obtain the whole-grain matrix powder. According to the invention, a certain amount of beans are added into grains, so that reducing sugar and protein are subjected to Maillard reaction, and dextrin, fatty acid and protein are subjected to chemical reaction, so that the flavor and reconstituability of the whole-grain matrix powder are ensured. According to the invention, a multi-enzymolysis combined extrusion puffing process is adopted, so that the contents of amylose and resistant starch in the whole grain matrix powder are increased, and the blood sugar stability of diabetic patients is favorably maintained. Meanwhile, the content of biological accessible polyphenols is also increased, and the blood sugar level of a diabetic patient can be effectively reduced.

This invention discloses a starch-quercetin complex enzymatic hydrolysate, its preparation method, and its application, relating to the field of starch preparation technology. The preparation method of the starch-quercetin complex enzymatic hydrolysate includes the following steps: mixing starch and water, heating and gelatinizing to obtain a starch paste; mixing the starch paste and quercetin, stirring to obtain a starch-quercetin complex gel; and mixing the starch-quercetin complex gel and pullulanase under pullulanase enzymatic hydrolysis temperature and pH conditions to perform enzymatic debranching reaction, obtaining the starch-quercetin complex enzymatic hydrolysate. By mixing starch and quercetin to form a complex before enzymatic debranching treatment, the local inhibitory effect of quercetin on the starch debranching process is utilized, achieving directional regulation of starch chain length distribution, selectively enriching the long branches in DP25-76, ultimately reducing the content of rapidly digestible starch and increasing the content of slowly digestible starch and resistant starch, thus altering the digestibility of starch.

This invention relates to a method for preparing a nano-starch-based glutinous rice ball conditioner. First, starch is sequentially debranched using pullulanase and then fractionated by alcohol precipitation to obtain debranched and fractionated starch components with different chain length distributions. These debranched and fractionated starch components are dispersed in water and gelatinized at 85-95°C for 5-20 min to prepare a 1%-10% (w / v) starch paste. The paste is then homogenized under high pressure at 10000-20000 rpm for 1-5 min, followed by the addition of 50-200 mL of anhydrous ethanol as a countersolvent to rapidly induce nucleation and form a polycrystalline nano-starch precursor. Next, the obtained nano-starch precursor suspension is incubated in a water bath at 20-90°C for 15-60 min while stirring at 300-1000 rpm. It is then cooled to room temperature and centrifuged at 4000-12000 rpm for 5-20 min. The precipitate is washed with anhydrous ethanol and centrifuged again to obtain nano-starch in different morphologies. Finally, the obtained nano starch was applied to glutinous rice balls and it was found that it could significantly reduce the mixing rate and freezing crack rate of glutinous rice balls, and improve their storage stability and eating quality.

The invention relates to a waste paper recycling method and application thereof, and belongs to the technical field of waste paper recycling. The invention provides a waste paper recycling method which comprises the following steps: S1, adding a compound enzyme into a reaction kettle, heating to 40-50 DEG C, adding waste paper, pulping, performing ultrasonic treatment, performing enzymolysis, and filtering to obtain pretreated fiber pulp; s2, transferring the pretreated fiber pulp into a photocatalytic reaction tank for reaction; s3, spraying a nano material to form a Zeta potential gradient, transferring into an electromagnetic field treatment device, carrying out directional arrangement, dehydrating, and drying to obtain paper; wherein the compound enzyme is prepared from cellulase, xylanase, laccase and pullulanase. According to the method, key indexes such as deinking efficiency, fiber protection, bleaching performance and mechanical strength are remarkably improved, the technical bottleneck in recycling of the oil-containing waste packing paper is successfully solved, and a breakthrough scheme is provided for production of high-added-value regenerated paper pulp.

This invention discloses a pullulanase PulW310B, whose amino acid sequence is shown in SEQ ID NO:1. It is a type II pullulanase with 4-α transglycosylation activity, capable of efficiently synthesizing high-content maltohexasaccharide and maltononose using maltotriose as donor and acceptor. This invention provides a new route for synthesizing highly polymerized maltooligosaccharides. Furthermore, the pullulanase PulY103B of this invention is simple to prepare, produces few byproducts in the synthesized product, and is suitable for industrial production and market application.

The invention relates to a preparation method of a saccharide isomeride with strong moisturizing and relieving effects as well as a product and application of the saccharide isomeride. The preparation method comprises the following steps: mixing corn starch with water to prepare starch milk, and performing acidolysis, neutralization, composite enzymolysis, saccharification and cooling crystallization to prepare D-glucose crystals; mixing the D-glucose crystal with water and glucose isomerase for reaction, and performing enzyme deactivation and concentration to obtain a saccharide isomeride; wherein the enzyme in the composite enzymatic hydrolysis comprises a combination of alpha-amylase, pullulanase and beta-amylase. The specific enzyme combination is adopted to decompose and extract the saccharide isomeride component in the corn starch, a potential synergistic relationship exists among the three enzymes, the extraction effect can be remarkably improved after the three enzymes are combined, and the prepared saccharide isomeride product has excellent moisturizing and soothing effects.

The invention discloses a method for removing and degrading starch by a compound enzyme system in a pulping process of waste box boards, which comprises alpha-amylase, beta-amylase, glucoamylase, pullulanase and pectinase. OCC white water and OCC paper pulp are subjected to enzymolysis through alpha-amylase and another three kinds of compound enzymes (beta-amylase, pullulanase and glucoamylase) which are compounded (the enzyme activity is conventional enzyme activity), and when the dosage of the compound enzymes is 1000 mL * t <-1 >, the enzymolysis rate of the compound enzymes is far superior to that of single alpha-amylase with the dosage of 5000 mL * t <-1 > at the same enzymolysis time; the starch decomposition rate of the waste paper pulp is increased by 3.75 times and reaches 42.8%, and the white water is correspondingly increased by 38% and reaches 42.8%.

The invention belongs to the technical field of enzyme preparations and biological fermentation, and relates to a composite saccharifying enzyme for producing alcohol from thick mash corn and a use method of the composite saccharifying enzyme, and the composite saccharifying enzyme contains 70-90% of glucoamylase, 5-10% of pullulanase, 5-8% of acid protease and 3-5% of xylanase according to the enzyme activity unit ratio. The use method of the composite saccharifying enzyme in production of alcohol from thick mash corn comprises the following steps: S1, sieving corn flour, adding water, uniformly mixing, then adding alpha-amylase, heating, and liquefying to obtain liquefied mash; and S2, cooling the liquefied mash, adjusting the pH to be acidic, adding a compound saccharifying enzyme and saccharomyces cerevisiae, synchronously performing saccharification and fermentation treatment, and distilling after the treatment is completed to obtain the alcohol. The composite saccharifying enzyme disclosed by the invention can solve the problems of low starch utilization rate, high mash viscosity, more residual sugar and the like in the alcohol fermentation of the thick mash corn.

The invention discloses a method for preparing anti-digestible long-shaped rice flour by utilizing a double-enzyme method in cooperation with extrusion treatment, and belongs to the technical field of functional food. The method for preparing anti-digestible long-shaped rice flour through cooperation of a double-enzyme method and extrusion treatment comprises the following steps: fully mixing long-shaped rice flour raw materials with medium-temperature alpha-amylase and pullulanase, carrying out primary extrusion debranching through a double-screw extruder, collecting the debranching long-shaped rice flour, and drying and crushing the long-shaped rice flour; and fully mixing the obtained debranched long-shaped rice flour with monoglyceride, and performing secondary extrusion by using a twin-screw extruder to realize the formation of the anti-digestible long-shaped rice flour in the secondary extrusion. According to the method, high-concentration long-shaped rice flour and high-efficiency preparation of digestion-resistant long-shaped rice flour in a short time are realized, and the problems of complex preparation process, low raw material concentration, long preparation time and low compounding efficiency of a starch-lipid compound are solved; the content of the RS5 type resistant starch is increased, and a theoretical basis and actual guidance are provided for continuous industrial production of the resistant starch.

A Saccharomycopsis fibuligera strain, a microbial agent, a fermentation product, preparation and a use. The Saccharomycopsis fibuligera strain is preserved in the China Center for Type Culture Collection on 25 September 2023, with the preservation number of CCTCC NO: M20231788. The Saccharomycopsis fibuligera strain can be used to produce multiple enzymes required by fermentation, such as amylase, protease, and cellulase, wherein the amylase has the activities of pullulanase and raw starch amylase, can well adapt to special environmental conditions for fermentation, and has high environmental tolerance and high aroma production capability, thereby improving the quality of fermentation products, and reducing investment costs in fermentation production.

The present application belongs to the technical field of grain deep processing and functional carbohydrate material, and relates to a waxy corn starch-guar gum compound as well as a preparation method and application thereof. The present application adopts high-pressure homogenization assisted pullulanase debranching to prepare RS3, and then mixes and embeds the RS3 with guar gum in a dry state according to a dry basis mass ratio of 6% to 24% to construct a physical barrier, and finally performs autoclaving treatment on the RS3 to strengthen the structure under a water content of 20% to 40%, so as to obtain a waxy corn starch-guar gum compound with high resistance and heat resistance. The compound presents ABV type XRD characteristic peaks, the crystallinity is greater than or equal to 65%, the resistant starch (RS) content can reach more than 50%, and the gelatinization peak temperature is significantly improved, thereby solving the problem that the existing RS3 is prone to uncoiling and the anti-digestion performance is reduced during high-temperature processing, and expanding the application of waxy corn starch in healthy functional food.

The invention belongs to the technical field of food processing, and particularly provides a compound preparation for improving the rancidity of bamboo powder, which comprises a compound enzyme A and a compound enzyme B, the compound enzyme A comprises neutral protease, lipase, glucose oxidase and catalase; the compound enzyme B is prepared from medium-temperature alpha-amylase, saccharifying enzyme and pullulanase. According to the composite preparation for improving the rancidity of the bamboo powder, specific enzymes are combined, and an optimized step-by-step enzymolysis process is combined, so that oxidation products causing the rancidity in the bamboo powder can be effectively degraded, or the formation way of the oxidation products can be blocked, the bamboo flavor can be remarkably reduced or eliminated, and meanwhile, main nutritional ingredients and quality of the bamboo powder are kept.

The invention discloses a fusion protein based on adhesion promoting antibacterial peptide, an enzyme immobilization system and a preparation method and application thereof. The fusion protein contains adhesion promoting antibacterial peptide and target protein, the adhesion promoting antibacterial peptide is selected from at least one of DS1, LCI and TA2, and the target protein is selected from at least one of green fluorescent protein eGFP and pullulanase pul. According to the fusion protein and enzyme immobilization system constructed by the invention, the target protein can be immobilized on immobilization carriers in different scenes, so that the target protein is recycled, and the fusion protein and enzyme immobilization system has the advantages of simplicity in operation, convenience, rapidness, high immobilization efficiency, good enzyme activity and stability and the like.

The invention belongs to the field of food additives and specifically discloses a preparation process and application of lipophilic composite modified starch; the preparation process comprises the following steps: 1) using cassava starch as a raw material, and after mechanical activation, phosphorylating and cross-linking the cassava starch to obtain phosphate-modified starch; 2) pretreating the phosphate-modified starch to obtain a pretreatment liquid, and performing three-enzyme continuous modification and denaturation on the pretreatment liquid, wherein the three-enzyme continuous modification and denaturation comprises the following steps: 21) starch branching enzyme modification and denaturation, 22) beta-amylase modification and denaturation, and 23) pullulanase modification and denaturation; the starch of the invention is modified by sodium trimetaphosphate and subjected to three-enzyme continuous modification and denaturation at the same time, thereby compensating for the defects of single enzyme modification, and the obtained product has the dual properties of cross-linked starch and esterified starch, has the advantages of good hydrophilic and lipophilic properties, high viscosity, freeze-thaw resistance, dehydration (aging) resistance, and the like, thereby making the product have better practicality.

The invention discloses a preparation method of Lipu taro meatballs with a low glycemic index, and belongs to the technical field of taro processing. The preparation method comprises the following steps: quickly freezing fresh Lipu taros, and crushing to obtain Lipu taros powder; separating mucus and starch of the Lipu taro powder by taking rice wine as a solvent and adopting a subcritical fluid extraction method; carrying out enzymolysis treatment on the Lipu taro starch primary product by using pullulanase and isoamylase to obtain enzymolysis slurry; preparing meat balls by using minced streaky pork, the enzymolysis slurry, Lipu taro mucus, cassava starch, curdlan, composite phosphate, table salt, white pepper powder, egg white, minced scallions, fresh ginger and chicken essence as raw materials, and curing to obtain the Lipu taro meat ball finished product with the low glycemic index. The Lipu taro meat ball with the low glycemic index is a low-GI food, is suitable for being eaten by vast consumers, is particularly suitable for being eaten by people with sugar and fat control requirements, and has the characteristics of high yield, low cooking loss rate, high water retention rate, good texture property and the like.

This invention discloses a method and application for preparing whey protein isolate microgels based on enzymatic hydrolysis of OSA-modified starch, belonging to the field of emulsion gelation technology. The preparation of the whey protein isolate microgels of this invention includes the following steps: dissolving OSA-modified starch in phosphate buffer, gelatinizing in a boiling water bath, cooling, adding pullulanase for enzymatic hydrolysis, boiling to inactivate the enzyme, then adding β-amylase for secondary enzymatic hydrolysis, centrifuging, collecting the supernatant, and freeze-drying to obtain EOSA starch; preparing whey protein isolate solutions and EOSA starch solutions separately, mixing them at a 1:1 volume ratio, homogenizing, and obtaining the final microgel. The microgel particles have a smooth surface and a uniform gel network structure; they can effectively stabilize the emulsion morphology, exhibiting good storage and thermal stability; furthermore, they are suitable for the preparation of swallowable foods, and the degree of enzymatic hydrolysis of OSA-modified starch can be adjusted to control the swallowability grade, adapting to different swallowability requirements.

The invention discloses a preparation method of a low-purine white kidney bean product, relates to a preparation method of a white kidney bean product, and belongs to the technical field of food processing. The invention aims to solve the problems of low purine degradation rate, large nutrient loss, long process period and poor flavor in the prior art. The preparation method comprises the following steps: mixing bean flour with water, adjusting the pH value, adding pullulanase and beta-amylase, carrying out enzymolysis and enzyme deactivation, and cooling to room temperature to obtain an enzymatic hydrolysate; inoculating a mixed bacterial solution of lactobacillus plantarum and saccharomycetes into the enzymatic hydrolysate, fermenting, sterilizing, centrifuging, and drying to obtain the product. Through the innovative biological synergistic effect, namely, the dual effect of enzymolysis release and microbial degradation, the total purine content in the white kidney bean product is reduced by 40% or above, the balance of nutrition retention and function enhancement is achieved, the sensory quality of the product is actively improved, and the processing period is remarkably shortened to 24-48 hours.

The invention discloses a preparation method of low-GI whole-grain furnace fruits rich in dietary fibers, and the preparation method of the low-GI whole-grain furnace fruits rich in dietary fibers comprises the following steps: step 1, extracting low-GI whole-grain starch; step 2, treating the compound powder with pullulanase; and step 3, preparing the whole-grain furnace fruits. On the premise of ensuring the taste, the blood glucose generation index of the traditional old-fashioned oven fruit is reduced, and the food selection of sugar-controlled people is enriched; meanwhile, multiple cereals are compounded, on the premise of low GI, the product is richer in nutritional value, rich in dietary fibers and flavonoid substances, and beneficial to promoting intestinal tract movement and maintaining heart and cerebral vessel health; the GI value is reduced through pullulanase treatment, the specificity is higher, the purpose of reducing the GI value of a product can be better achieved, the method is low in investment, environmentally friendly and capable of specifically acting on carbohydrates in food, the structure of the carbohydrates is changed through hydrolysis, and therefore the GI value of the food is effectively reduced.

The utility model belongs to the technical field of wheat wetting and debranching devices, and discloses a wheat wetting device for preparing low-GI wheat flour by using pullulanase debranching, which comprises a tank body, a mixing box, a heating layer, a vibrating device, a stirring device and a spraying device, a mixing box with an opening in the top is arranged in the tank body, and a discharging opening matched with the discharging opening is formed in the bottom of the mixing box; a vibration device is arranged at the bottom of the mixing box; a heating layer is arranged between the inner wall of the tank body and the outer wall of the mixing box; a stirring device is arranged in the cavity of the mixing box; a spraying device is arranged on the top wall of the tank body; a feeding port is formed in the top of the tank body, and a discharging port is formed in the bottom of the tank body. By adopting the stirring, vibrating, heating and enzyme liquid spraying devices, the wheat wetting time is shortened, the wheat wetting efficiency is improved, and the enzymolysis debranching reaction is carried out while the wheat is wetted, so that the low-GI wheat flour is prepared.

The application discloses a kind of disulfide crosslinked starch-based micelles and its preparation method and application.The preparation method includes: using pullulanase to carry out branch removal treatment to waxy corn starch, and prepare dextrin;Using periodate on the dextrin is oxidized, and prepare dialdehyde dextrin;Make cysteamine and the dialdehyde dextrin grafting reaction, and prepare cysteamine-dextrin;The cysteamine-dextrin is dissolved in water and self-assembled to form micelles, then ultrasonic sulfhydryl oxidation is carried out, and prepare disulfide crosslinked starch-based micelles.The disulfide crosslinked starch-based micelles provided by the application with hydrophobic functional factor has higher hydrophobic functional factor loading and environmental stress stability, in vitro simulation release presents colon targeting, and has wide application prospect in the field of oral delivery of hydrophobic functional factor.

This invention relates to a pullulanase mutant with improved glycogen debranching activity, its preparation method, and its applications, belonging to the fields of enzyme engineering and biotechnology. The mutant is obtained by mutating tryptophan at position 81 of the type I pullulanase shown in SEQ ID NO.1 to alanine or tyrosine, with amino acid sequences shown in SEQ ID NO.2 and SEQ ID NO.3, respectively. Enzymatic performance tests show that this mutant significantly enhances the hydrolytic ability of glycogen while maintaining its original catalytic activity, providing a tool for the controlled synthesis and modification of glycogen. This invention also provides the gene encoding the mutant, a recombinant vector containing the gene, an engineered bacterium, and the application of the mutant in glycogen debranching. The pullulanase mutant provided by this invention can be effectively used for glycogen debranching treatment, expanding the application scope of type I pullulanase in glycogen-related fields.