204 results about "Alkaline proteinase" patented technology

The invention provides a whey protein deep hydrolysate with low sensitization and an allergy relieving effect as well as a preparation method and application of the whey protein deep hydrolysate. According to the method, the alkaline protease, the neutral protease and the glutamyltransferase are sequentially used for carrying out first enzymolysis, second enzymolysis and third enzymolysis on the whey protein raw material, and the whey protein hydrolysate which is low in molecular weight, good in taste, good in digestion and absorption performance, low in sensitization and capable of effectively relieving allergic reaction of the organism is obtained.

The invention discloses a preparation method for simultaneously and efficiently extracting crocodile polypeptide and crocodile oil, and relates to the technical field of biological extraction, crocodile meat is used as a raw material, and heating micro-pressure treatment is sequentially performed to promote component dissolution; a multi-stage enzymolysis process is adopted, alkaline protease, neutral protease and lipase are sequentially used, and a calcium phosphate system is used for assisting filtration and a natural antioxidant is added in a gradient manner in the enzymolysis process; performing plate frame filtration and standing layering subsequently to realize crude separation of the oil peptide; finally, the crocodile polypeptide liquid is subjected to multi-stage membrane filtration and spray drying, the crocodile crude oil is subjected to ultrasonic-assisted fishy smell removal, ceramic membrane fine filtration and gradient cooling phase change refining, and after enzymolysis treatment and before filtration, a composite additive is added into enzymatic hydrolysate and stirred. No organic solvent exists in the whole process, and the product yield, purity and oxidation stability are remarkably improved.

The invention discloses a corn peptide for dispelling effects of alcohol and protecting liver as well as a preparation method and application thereof, and belongs to the technical field of biological peptide extraction. The preparation method comprises the following steps: crushing and sieving corn, dissolving the corn in deionized water, adjusting the pH value to be alkaline, and performing ultrasonic-assisted extraction to obtain corn homogenate; centrifuging, taking supernate, adjusting the pH to be neutral, centrifuging, adding an ethanol solution with the mass fraction of 10%, standing, carrying out continuous flow centrifugation, suspending precipitates in distilled water, dialyzing in a dialysis bag, and freeze-drying to obtain crude corn protein; the preparation method comprises the following steps: preparing an aqueous solution, carrying out variable-temperature treatment, adjusting the pH value to be alkaline, adding trypsin and alkaline protease, carrying out enzymolysis, repeating the enzymolysis twice, and after the enzymolysis is finished, carrying out heating enzyme deactivation, centrifugation, sediment discarding, ultrafiltration, centrifugation, supernatant taking and spray drying to obtain the corn peptide. The corn peptide can remarkably shorten the drunkenness time and sobering time of mice and reduce the drunkenness duration, and has good effects of dispelling the effects of alcohol and protecting the liver.

The invention provides a nutrition enhancer beneficial to bone health of middle-aged and elderly people, a preparation method of the nutrition enhancer and application of the nutrition enhancer in preparation of medial care food, and belongs to the field of nutritious food. The nutrient supplement comprises a plant fermentation product, osteopontin peptide, collagen peptide, N-acetylglucosamine and calcium, vitamins and mineral substances can be added, and the plant fermentation product is obtained by performing anaerobic fermentation on rhizoma drynariae and chestnuts through a complex microbial inoculant composed of lactobacillus reuteri and bifidobacterium longum subsp. Longum; the collagen peptide is prepared by performing enzymolysis on bovine bones through alkaline protease and flavourzyme; the hydrogel is prepared by adopting a sodium alginate-calcium chloride-carboxymethyl chitosan micro-capsule embedding process. An in-vitro experiment shows that the nutrition enhancer can remarkably promote osteoblast proliferation, differentiation and mineralization; animal experiments show that the bone mineral density of osteoporosis model mice can be effectively improved. The nutrition enhancer disclosed by the invention is suitable for preparing care food and bone health products, and has a remarkable effect of improving bone health of middle-aged and elderly people.

The invention discloses a method for preparing high-F-value oligopeptide from whey protein, and belongs to the technical field of food biology. According to the method, whey protein is taken as a raw material, step-by-step synergistic enzymolysis of alkaline protease-chymotrypsin-flavourzyme is performed, and an activated carbon selective adsorption dearomatization process is combined, so that the F value and the hydrolysis degree of oligopeptide are remarkably improved. The enzymolysis efficiency is high, and the final hydrolysis degree is gt; 30%; the dearomatization effect is excellent, and the product F value is gt; 26; the method is simple in process and low in cost, high-value conversion of whey protein can be achieved, and the prepared high-F-value oligopeptide can be applied to the fields of sports nourishment, food for special medical purposes and the like and has remarkable industrial value.

The invention discloses camellia seed meal oligopeptide as well as a preparation method and application thereof. The method comprises the following steps: S1, pretreating camellia seed meal to obtain a pretreated substance; s2, performing enzymolysis and wall breaking to obtain first enzymatic hydrolysate; wherein the enzymolysis wall breaking adopts a mixed enzyme, and the mixed enzyme comprises amylase and cellulase; s3, extracting crude protein to obtain crude protein; s4, carrying out crude protein enzymolysis on the crude protein to obtain a second enzymatic hydrolysate; wherein the crude proteolysis adopts mixed protease, and the mixed protease comprises first protease and second protease; wherein the first protease is one or more of alkaline protease, neutral protease and acid protease; the second protease is papain; and S5, purifying the second enzymatic hydrolysate to obtain the camellia seed meal oligopeptide. The average molecular weight of the obtained product is smaller than 1000 Daltons, and the product has biological activity and high application value in the fields of cosmetics and functional food.

The invention relates to the field of polypeptides, in particular to a black ginseng polypeptide and a preparation method and application thereof. The black ginseng polypeptide is obtained by taking black ginseng as a raw material through high-pressure homogenization wall breaking and alkaline protease enzymolysis. The polypeptide has an anti-aging function. The black ginseng polypeptide provided by the invention is more efficient, safer and more environment-friendly, and has a good application prospect in the fields of cosmetics, functional foods and biological medicines.

The application discloses a method for preparing oil-tea camellia seed oil by alkaline protease and endogenous protease synergistic demulsification, which comprises the following steps: 1) collecting emulsion; 2) extracting endogenous protease; 3) alkaline protease and endogenous protease synergistic demulsification: adding distilled water and alkaline protease into the emulsion for primary enzymolysis, the adding amount of the alkaline protease is 0.5-2% of the weight of the emulsion, the primary enzymolysis time is T1, and 60min<=T1<75min, adding endogenous protease according to 0.6-1.4% of the weight of the emulsion for secondary enzymolysis, the secondary enzymolysis time is T2, and 15min<=T2<=35min, the total time of the primary enzymolysis and the secondary enzymolysis is less than 100min, and oil emulsion is obtained; 4) enzyme inactivation and centrifugation, and oil-tea camellia seed oil is obtained. The alkaline protease and the endogenous protease are used for synergistic demulsification, which can not only improve the demulsification rate and the extraction rate of the oil-tea camellia seed oil, but also inhibit the generation of bitter amino acids, so that the prepared oil-tea camellia seed oil does not contain bitterness, and the flavor and quality of the oil-tea camellia seed oil are improved.

The present application relates to the technical field of small molecule peptide preparation, and specifically discloses a preparation process of selenium-rich antioxidant pig lung polypeptide. The preparation process of the selenium-rich antioxidant pig lung polypeptide comprises the following steps: washing and decontaminating fresh pig lung, peeling off the trachea, removing grease, and twisting into a minced meat shape to obtain pig lung pre-preparation material; mixing the pig lung pre-preparation material with a vitamin C aqueous solution, adding nano-silicon dioxide powder and eugenol to the mixture, and performing ultrasonic treatment; cooling to-10 to-30 DEG C, keeping for 1 to 2 hours, and then increasing the temperature to room temperature; homogenizing treatment, filtration, collecting the precipitate, and obtaining pretreated pig lung; adding water to the pretreated pig lung and stirring until uniform; adjusting the pH value of the system; adding a stabilizing alkaline protease for treatment; adjusting the system to be neutral; adding a neutral protease for enzymolysis; and cooling to room temperature to obtain pig lung enzymolysis liquid; centrifuging the pig lung enzymolysis liquid, ultrafiltering, collecting the permeate, nanofiltrating, collecting the concentrated liquid, and drying.

The application provides a mung bean protein salty taste enhancing peptide, a screening and preparation method and application. The method comprises the following steps: step 1, carrying out step-by-step enzymolysis on mung bean protein by using alkaline protease and flavor protease, carrying out ultrafiltration grading, and screening an initial extract of the salty taste enhancing peptide by using an electronic tongue; step 2, further identifying polypeptide sequences by using LC-MS / MS; and step 3, screening polypeptides with strong interaction capability with salty taste receptors TMC4 and ENaC by combining biological activity prediction, target active fragment screening, safety and physicochemical property evaluation and molecular docking analysis. The salty taste enhancing peptide of the mung bean protein obtained by screening comprises polypeptides represented by RPFF, APDLRGY, WDDIGGL, FDGF and AEFF, and contains RP, RG, DD, DGF and FF characteristic peptide segments, respectively. The polypeptides are synthesized by using a solid phase, and the salty taste enhancing effect of the polypeptides is verified by using an electronic tongue. When 0.03% of the above synthesized polypeptides are added to a 0.4% NaCl solution, the salty taste enhancing rates are 90%, 62%, 34%, 52% and 42%, respectively. The polypeptides can significantly enhance salty taste perception of a solution under low-salt conditions, and achieve the effect of salt reduction without taste reduction.

The invention discloses a composition for improving adverse effects of chemotherapy as well as a preparation method, application and a product of the composition, and particularly relates to the technical field of medicines. The composition comprises the following raw materials: tortoise, soft-shelled turtle, antler, sea cucumber, fructus amomi, pericarpium citri reticulatae and hawthorn. Alkaline protease and flavourzyme are adopted for enzymolysis, and the obtained composition can remarkably reduce the tumor volume of tumor-bearing animals, increase the bone marrow DNA content of chemotherapy animals and remarkably increase the number of white blood cells and the number of red blood cells in peripheral blood of the chemotherapy animals. The composition disclosed by the invention is used for preparing related products for improving the adverse effects of chemotherapy, and the prepared products are easy to absorb and have a remarkable improvement effect on the adverse effects of chemotherapy.

The present disclosure belongs relates to a 2709 alkali protease mutant modified based on molecular dynamics calculation and use thereof in liquid detergents. The dynamic structure feature of a 2709 alkali protease derived from Bacillus licheniformis are studied by using a molecular dynamics method through computer simulation, which is a unique effective method capable of studying a relationship between the structure of the 2709 alkali protease and molecular dynamics as well as an enzyme function in an atomic level. After molecular dynamics calculation, appropriate sites are selected for protein engineering to obtain the 2709 alkali protease mutant suitable for industrial application of detergents. The protease mutant has significantly improved enzyme activity under the alkaline condition, is better in stability, not only has good decontamination effect but also has good component compatibility with components in the detergent, and can be widely applied to the field of washing industry.

The invention relates to a novel amino acid foliar fertilizer and a preparation method thereof, and belongs to the technical field of agricultural fertilizers. The method aims at solving the technical problems that in the prior art, the amino acid conversion rate is low, product stability is poor, and severe conditions such as strong acid and strong alkali are possibly used. The method comprises the following steps: mixing soybean meal, fish meal and saccharomyces cerevisiae thalli to form a compound protein raw material, performing two-stage crushing and degreasing, performing step-by-step enzymolysis by adopting a compound enzyme preparation compounded by alkaline protease and flavourzyme, performing enzyme deactivation, and performing ultrafiltration by adopting a ceramic membrane to obtain purified amino acid hydrolysate, and mixing the hydrolysate with a composite trace element mixed solution formed by EDTA-Fe, EDTA-Zn, boric acid, ammonium molybdate and citric acid, adding humic acid, a seaweed extract and an organic silicon penetrant, and carrying out high-speed shearing, filtering and vacuum degassing to finally obtain the product. The method is mainly used for producing the amino acid foliar fertilizer which is high in free amino acid content, good in stability and easy to absorb by plants.

The invention belongs to the technical field of plant pharmacy, and particularly relates to an effect of pigeonpea in resisting respiratory syncytial virus infection. Detecting that the pigeon pea protein extract is non-toxic to HEp-2 cells through a cell proliferation detection kit; a cell activity detection method and an indirect immunofluorescence method are adopted to determine that the pigeon pea protein extract has an obvious inhibition effect on the respiratory syncytial virus, the activity of inhibiting the respiratory syncytial virus after the pigeon pea protein is subjected to enzymolysis by alkaline protease is improved, and pigeon peas have relatively high biological safety and relatively strong respiratory syncytial virus infection resistance.

The invention provides a controllable enzymolysis method for improving the utilization rate of sunflower seed meal protein, which comprises the following steps: crushing sunflower seed meal, mixing with water, and carrying out alkali extraction to obtain a protein crude extract; the method comprises the following steps: carrying out enzymolysis on compound protease prepared from alkaline protease, papain and flavourzyme according to the mass ratio of (1-2): (2-1): 0.1 at the pH of 7-8 and the temperature of 48-50 DEG C, and ensuring that the enzyme adding amount is 1.5-3% of the mass of protein; the hydrolysis process is controlled by regulating and controlling enzymolysis conditions in stages; and finally, carrying out enzyme deactivation, separation and drying to obtain a hydrolysate. According to the method, efficient and controllable hydrolysis of sunflower seed meal protein is achieved, the protein recovery rate reaches 75.61%, the solubility reaches 98.14%, the bitter taste of the product is low, and the method is suitable for large-scale production.

The novel plant protease modification production system comprises a material conveying and processing channel, wherein the material conveying and processing channel is formed by sequentially connecting a steam ejector, an enzymolysis pipeline static mixer, an enzymolysis tank, an enzymolysis maintaining tank, an enzymolysis discharge pump, an acid precipitation pipeline static mixer, an acid precipitation tank, an acid precipitation maintaining tank and an acid precipitation discharge pump through pipelines; a material inlet of the steam ejector is connected with an alkali-soluble protein material liquid conveying pipeline, a steam inlet of the steam ejector is communicated with the steam conveying device through a pipeline, liquid inlets of the enzymolysis pipeline static mixer and the acid precipitation pipeline static mixer are both connected with an acid liquid pipeline, and the top of the enzymolysis tank is connected with an alkali protease pipeline. The alkaline protease is directly and quantitatively added into the enzymolysis tank for enzymolysis reaction. According to the device disclosed by the utility model, an enzymatic modification process of vegetable protein is introduced into a vegetable protein preparation process, so that the modification efficiency of the vegetable protein is improved, the whole production is more continuous, and the number of equipment increased due to introduction of an enzymatic modification production system is reduced to the greatest extent.

The invention provides an extraction method and application of sweet potato protein, belongs to the field of agricultural product processing, protein extraction and pharmaceutical activity application, and particularly provides an extraction method of sweet potato protein, an extraction solvent is mainly water, and NaHSO3 is assisted; the sweet potato protein with a single structure and high purity is obtained through modes of cutting, crushing, centrifuging, filtering, freeze-drying and the like, and the method is suitable for industrial production and amplification; the invention further provides sweet potato protein peptide which is obtained by conducting enzymolysis on sweet potato protein through neutral protease or alkaline protease, and the obtained sweet potato protein and sweet potato protein peptide have the anti-inflammatory and anti-tumor effects.

The invention provides bacillus licheniformis for high-yield protein glutaminase as well as a construction method and application of the bacillus licheniformis, a target strain is obtained by knocking out an alkaline protease gene aprE and extracellular protease genes bpr, epr, vpr or wpr and heterologously expressing the protein glutaminase gene, an EPE strain is optimal in expression, PG enzyme activity reaches 0.358 U / mL and is improved by 3.55 times compared with that of a wild type, and the bacillus licheniformis has the advantages that the bacillus licheniformis is high in yield and high in protein glutaminase yield. In addition, the growth condition of each mutant strain is not obviously abnormal, and the growth speed is obviously increased. It is fully proved that the expression level of the heterologous protein PG can be remarkably improved by targeted knockout of the extracellular protease gene of the bacillus licheniformis, and a theoretical basis is laid for construction of an efficient protein expression host. The invention not only provides a new scheme for high-efficiency expression of PG, but also provides important reference for expression optimization of heterologous proteins of other gram-positive bacteria, and shows a wide industrial application prospect.

The present application relates to a preparation method of sea cucumber egg-derived peptide complex and application thereof.The preparation method of sea cucumber egg-derived peptide complex comprises the following steps: sea cucumber egg powder is subjected to synchronous enzymolysis by using alkaline protease and trypsin.Further separation is carried out through ultrafiltration, dextran gel chromatography and high performance liquid chromatography, sea cucumber egg-derived active peptides are obtained by using liquid chromatography-mass spectrometry technology, computer-aided screening technology and in-vitro verification, and the amino acid sequence of the sea cucumber egg-derived active peptides comprises one or several of WGN, WIGG and GFPVG.The sea cucumber egg-derived peptide complex and the sea cucumber egg-derived active peptides provided by the present application both have double activities of antioxidant and tyrosinase inhibition, can reduce melanin content, and have the advantages of good water solubility, good safety and the like.

The present invention relates to a method for producing an opioid peptide, a method for improving the production efficiency of an opioid peptide, and an alkaline protease composition for the production of an opioid peptide. The present invention addresses the problem of providing a method for efficiently producing an opioid peptide. The problem can be solved by a method for producing an opioid peptide according to the present invention, the method comprising a step for producing a peptide containing an amino acid sequence represented by SEQ ID NO: 2 by bringing an Aspergillus alkaline protease, which recognizes the amino acid sequence of SLXX and is cleaved between two XXs, into contact with A2-type casein.

The present application relates to a kind of by knocking out Bacillus subtilis SacB gene constructed chassis strain and its application, belong to genetic engineering, enzyme engineering and food engineering technical field.The present application is by SacB gene on the genome of Bacillus subtilis Knocking out, obtain a kind of can efficiently express aminopeptidase, alkaline protease Bacillus subtilis expression system, lay the foundation for the efficient expression of protein, promote the efficient expression and industrial production of aminopeptidase, alkaline protease.The chassis strain described above, in the case of carrying aminopeptidase, alkaline protease expression cassette, respectively, 48H shake flask fermentation, fermentation broth aminopeptidase enzyme activity is as high as 1666.7U / mL, with the enzyme activity of starting strain as contrast, enzyme activity is increased by about 30%;Fermentation broth alkaline protease enzyme activity is as high as 6348U / mL, with the enzyme activity of starting strain as contrast, enzyme activity is increased by about 20%.

The invention relates to a preparation method of a rice bran protein ACE inhibitory peptide, and belongs to the technical field of bioactive peptide preparation. The preparation method comprises the following steps: extracting rice bran protein from defatted rice bran, carrying out step-by-step enzymolysis by using alkaline protease and papain to obtain a rice bran protein ACE crude peptide solution, centrifuging, carrying out ultrafiltration by using a 3kDa ultrafiltration tube, and purifying by using gel chromatography to obtain the rice bran protein ACE inhibitory peptide. The process is simple and efficient, the cost is controllable, the obtained ACE inhibitory peptide not only has high ACE inhibitory activity, but also has high oxidation resistance, is rich in various bioactive amino acids, can be used for efficiently preparing active peptide with strong antihypertensive potential, and provides an ideal raw material for developing novel antihypertensive food, medicine and health care products.

The invention relates to the technical field related to microcapsules, in particular to a preparation method of a wheat alpha-glucosidase inhibitory peptide microcapsule, which comprises the following steps: by taking wheat vital gluten as a raw material, carrying out enzymolysis by alkaline protease to obtain alpha-glucosidase inhibitory peptide, and then carrying out enzymolysis by adopting a sodium alginate-chitosan composite wall material system to obtain the wheat alpha-glucosidase inhibitory peptide microcapsule. By optimizing key parameters such as the core-wall ratio of 1: 2.632, the calcium chloride concentration of 2.48% and the curing time of 31.83 min, the double-layer microcapsule with the pH response characteristic is prepared by an ionic gel method. The embedding rate of the prepared microcapsule reaches 78.26%, the 2-hour release rate in simulated gastric juice (pH 2.0) is smaller than or equal to 21.38%, the 4-hour accumulative release rate in simulated intestinal juice is larger than or equal to 84.98%, and stomach protection and intestinal targeted release of the active peptide are achieved; meanwhile, the peptide loss rate of the product under the storage condition of 4 DEG C is less than or equal to 11.13%, the loss rate in the environment with the pH value of 2.0 is only 12.72%, and the stability of the active peptide is remarkably improved. The obtained product can effectively protect the activity of the alpha-glucosidase inhibitory peptide and improve the bioavailability of the alpha-glucosidase inhibitory peptide, and a new scheme is provided for developing functional hypoglycemic food.

The invention relates to the technical field of genetic engineering and protein engineering modification, in particular to an alkaline protease mutant and application thereof. The present invention relates to a mutant comprising an amino acid sequence having at least 90% identity with SEQ ID NO: 1 and comprising a substitution of an amino acid at at least one position selected from the group consisting of 63, 109, 120, 154, 191, 261, 328 compared to SEQ ID NO: 1. The specific activity of the mutant is generally improved by 13.12%-79.32% compared with that of a wild type, the production cost of the enzyme can be reduced, and wide application of the enzyme in the industrial field is promoted.

The invention belongs to the technical field of medical latex gloves, and particularly relates to a micro-ammonia latex medical examination glove and a preparation method thereof. Comprising 100 parts of modified deproteinized natural concentrated latex, 1-2.5 parts of sulfur, 0.5-1.5 parts of zinc oxide, 0.5-1.5 parts of an accelerant, 1-2 parts of an antioxidant and 0.1-0.5 part of a surfactant, the preparation method of the modified deproteinized natural concentrated latex comprises the following steps: filtering fresh natural latex to remove impurities, supplementing ammonia to 0.05-0.1%, then adding a stabilizer, porous rod-like silicon dioxide and alkaline protease, and carrying out an enzymolysis reaction; centrifuging to obtain micro-ammonia deproteinized concentrated natural latex and porous rod-like silicon dioxide, washing the porous rod-like silicon dioxide with water, and mixing with the micro-ammonia deproteinized concentrated natural latex to obtain the micro-ammonia deproteinized concentrated natural latex. The protein removal rate is improved through the shearing and friction effects of the porous rod-like silicon dioxide, and the porous rod-like silicon dioxide is further used as a reinforcing agent to improve the mechanical properties of the gloves.

The invention relates to the technical field of genetic engineering and protein engineering modification, in particular to an alkaline protease mutant. According to the invention, on the basis of wild type alkaline protease AprE from bacillus clausii, a mutant containing a mutation site selected from the group consisting of T22S, S99A, S101G, P127Q, N138Q, G172A, F183D, V197I, P219W, A226G and N232D is provided. The enzyme activity stability of the mutant in a detergent is remarkably improved compared with that of a wild type, so that the alkaline protease can be widely applied to the field of washing.

The invention relates to the technical field of biology, in particular to Chinese yam active peptide and a preparation method and application thereof.The Chinese yam active peptide comprises active peptide and free amino acid, the mass content of the active peptide with the molecular weight of 180-1000 Da is larger than or equal to 65%, and the mass content of hydrophobic amino acid in the free amino acid is larger than or equal to 30%. The preparation method of the Chinese yam active peptide is easy and convenient to operate, through the synergistic effect of the neutral protease and the alkaline protease, on the premise that the hydrolysis degree of the Chinese yam peptide is improved, it can be prevented that a large number of amino acids are generated through excessive hydrolysis, glycoprotein in Chinese yam is subjected to sufficient enzymolysis, and the yield of the Chinese yam active peptide is increased. The Chinese yam peptide prepared by the method can protect the vitality of Vero cells and MRC5 cells, has the characteristics of high activity, small molecular weight and easiness in absorption, and can be widely applied to the fields of medicines, foods, health care products, cell culture additives and the like.

This application belongs to the field of biotechnology, specifically relating to giant salamander skin collagen peptides, their preparation methods, and applications. This application provides a method for preparing giant salamander skin collagen peptides. The method first pre-treats the fish skin, then performs ultrasonic-assisted extraction under acidic conditions to effectively promote collagen dissolution. The extract undergoes flocculation to remove impurities, significantly reducing interference from other proteins. The enzymatic hydrolysis stage employs a stepwise enzymatic hydrolysis strategy: first, a combination of alkaline protease and another specific protease is used for hydrolysis, sequentially cleaving the complex structure of giant salamander skin collagen to improve initial hydrolysis efficiency and generate specific intermediate peptides; subsequently, a flavor protease is added for further deep hydrolysis to achieve complete hydrolysis. This method has high enzymatic hydrolysis efficiency, controllable hydrolysis degree, concentrated molecular weight distribution of the obtained collagen peptides, high yield of the target product, and stable process.

The application discloses a preparation method of sturgeon peptide and application of the sturgeon peptide in improving immunity and sexual function. The method comprises the following steps: S1, one or more of sturgeon cartilage, fish bone and fish skin are crushed after being thawed, and pure water is added according to a material-liquid ratio of 1:3-1:4 and is pumped into an enzyme hydrolysis tank; S2, the enzyme hydrolysis tank is heated to 85-90 DEG C under the condition of a closed low pressure of 0.06-0.08 MPa, and protein is denatured for 15-20 min; S3, the temperature is reduced to 60-65 DEG C, the pH is adjusted to 8.0-8.5, 2‰-3‰ alkaline protease of the raw material amount is added, and constant-temperature enzyme hydrolysis is carried out for 170-190 min; the temperature is increased to 85-90 DEG C after the enzyme hydrolysis is completed, and the enzyme is inactivated for 14-16 min; S4, decolorization is carried out; S5, filtration and concentration are carried out; S6, vacuum concentration is carried out; S7, sterilization and drying are carried out, and sturgeon peptide finished products are obtained. The sturgeon peptide obtained by the preparation method has small molecular weight and high active ingredients.

The invention discloses preparation and application of a corn polypeptide with functions of inhibiting amyloglucosidase activity and promoting GLP-1 secretion, and belongs to the technical field of functional food. And the corn polypeptide is PYPR, PPAPR and PLRP (Poly Lactic Polymerase Chain Reaction). The corn polypeptide is obtained by enzymolysis of corn protein through alkaline protease, and is novel in structure and easy to prepare. The corn polypeptide can inhibit the activity of amyloglucosidase in vitro, can significantly promote GLP-1 secretion, and can up-regulate the expression of gcg and gc3 genes related to GLP-1 synthesis and a polypeptide recognition receptor GPR93 by regulating Ca < 2 + > influx and an ATP signal channel, thereby improving the steady state of blood glucose. The invention provides reference for developing functional food or health care products with the functions of reducing blood sugar and promoting secretion of insulin.