98 results about "Heat denaturation" patented technology

The invention relates to a quantitative detection method for thermal-denaturation and non-denaturation bovine alpha-lactalbumin in milk and milk products by applying an enzymolysis-liquid chromatography and mass spectrometry combination technology. The quantitative detection method comprises the steps as follows: taking a certain amount of milk or milk samples, dissolving and diluting the milk or milk samples in water to obtain solution with total protein content being about 1mg/mL; after volume metering, correctly sucking 500 mu L, adding an internal standard substance, reacting disulfide bond with dithiothreitol (DTT), alkylating to protect sulfydryl produced in reaction by iodoacetamide (IAA), and then conducting constant-temperature and constant-time enzymolysis with trypsin; and separating enzymolysis products by reversed phase liquid chromatography, conducting detection with a mass spectrum multiple reaction monitoring (MRM) manner, and calculating the result by an internal standard method. The quantitation limit of the method is 0.001g/100g; when adding amount is 0.2, 1.7 and 5.0g/100g, the recovery rate is 98.9-110.8% (n is equal to 6) and repeatability: RSD (Relative Standard Deviation) is smaller than 7.6%; and the quantitative detection method can be applicable to the quantitative detection of samples with different contents of bovine alpha-lactalbumin.

This invention relates to phytases, polynucleotides encoding them, uses of the polynucleotides and polypeptides of the invention, as well as the production and isolation of such polynucleotides and polypeptides. In particular, the invention provides polypeptides having phytase activity under high temperature conditions, and phytases that retain activity after exposure to high temperatures. The phytases of the invention can be thermotolerant and/or thermostable at low temperatures, in addition to higher temperatures. The phytases of the invention can be used in foodstuffs to improve the feeding value of phytate rich ingredients. The phytases of the invention can be formulated as foods or feeds or supplements for either to, e.g., aid in the digestion of phytate. The foods or feeds of the invention can be in the form of pellets, liquids, powders and the like. In one aspect, phytases of the invention are stabile against thermal denaturation during pelleting; and this decreases the cost of the phytase product while maintaining in vivo efficacy and detection of activity in feed.

The present invention provides a method for the rapid simultaneous production of a plurality of single-stranded DNA circles having a predetermined size and nucleotide sequence using pre-designed hairpin oligonucleotides containing complementary sequences for directing ligation to form dumbbell-shaped monomers followed by heat denaturation to yield single-stranded DNA circles.

The invention discloses a method for separating purified ferritins from biological tissues or engineering bacteria. The method comprises the following steps of: performing mechanical lapping or ultrasonication by taking ferritin-enriched animal tissues or organs or engineering bacteria which are collected by fermenting and contain recombination ferritin genes as a raw material for extracting ferritins to obtain uniform serum, performing heat denaturation treatment on the filtered uniform serum in water with the temperature between 70 DEG C and 75 DEG C for 20 minutes, and centrifugally extracting supernatant to obtain a crude protein solution; performing dialysis equilibrium on the obtain crude protein solution, performing nickel column affinity chromatography and eluting by using 250 mM of competitive imidazole buffer solution to obtain electrophoretically pure ferritins; and further performing sepHarose 6B molecular sieve exclusion chromatography on the ferritins to obtain monomer ferritins and polymer ferritins which are separated from each other. By adopting the method, electrophoretically pure ferritins can be obtained by directly performing nickel column affinity chromatography in the absence of tag, so that purifying steps of the ferritins are greatly eliminated.

The invention relates to a making method of instant fresh sea cucumber, which is characterized by comprising the following steps: opening the abdomen of a fresh and live sea cucumber, completely removing internal organs, washing with clear water, placing into manganese salt solution which is 1-10 times the weight of the sea cucumber, adding an organic acid for adjusting the pH value to 4.0-6.0, placing the whole into a microwave sterilizer for microwave heating to 40-75 DEG C, and performing heat insulation treatment for 5-60 minutes; taking the sea cucumber out of the solution, and using ethanol solution containing 0.1-1% of tea polyphenol and 0.1-10% of propolis for impregnation or spraying the ethanol solution on the outer surface and the outer surface of the body wall of the sea cucumber; and performing compound modified atmosphere packaging on the sea cucumber so as to get the instant fresh sea cucumber. The instant fresh sea cucumber made through the method is low in loss of nutritional ingredients, the heat denaturation of protein is avoided, the instant fresh sea cucumber further has good taste and no fishy and astringency smell, and is convenient to preserve and take, simple in processing technology, short in period and low in energy consumption, and subsidiary ingredients can further increase the health care function of the sea cucumber while being used for processing.

A production technology of formula milk powder comprises the following steps: 1, dissolving an auxiliary material in pretreated raw milk A through utilizing a vacuum mixing method to obtain an auxiliary material solution, and carrying out vacuum concentration of pretreated raw milk B to obtain concentrated milk, wherein the solid concentration of the auxiliary material solution is 40-50wt%; 2, carrying out steam spraying sterilizing treatment of the auxiliary material solution obtained in step 1; 3, adding the auxiliary material solution obtained in step 2 to the concentrated milk obtained in step 1, uniformly mixing, and preheating to 65-75DEG C; and 4, carrying out spray drying to obtain the formula milk powder. The production technology only needs the raw milk B subjected to the vacuum concentration pretreatment, so the concentration evaporation amount is reduced, and the energy consumption is reduced; and simultaneously the vacuum concentration heat treatment of heat-sensitive raw materials comprising concentrated whey protein powder, vitamins and the like is avoided, so the protein heat denaturation and the heat losses of the heat-sensitive raw materials are reduced, and the nutritional quality of the formula milk powder is improved.

The present invention discloses one kind of recombinant analogous human collagen and its biological synthesis process. The recombinant analogous human collagen consists of one collagen region and one non-collagen region. The non-collagen region in the carboxyl group end of the collagen region has one amino acid sequence originated the minor fibrin of T4 bacteriophage and as shown in SEQ ID No. 3, and the collagen region has the amino acid sequence shown in SEQ ID No. 2. The recombinant analogous human collagen has relatively high heat stability, high hydrophilicity, high biocompatibility, heat denaturation temperature and heat decomposition temperature higher than that of natural collagen, and stable structure. It may be applied widely in biomedicine material, tissue engineering, cosmetics, food and other fields.

The invention provides a method for extracting oil camellia seed polypepetide from oil camellia seed protein. The method sequentially comprises the following steps of preparing the oil camellia seed protein, crushing, screening, adding water to obtain suspension, carrying out heat denaturation treatment, regulating pH value, carrying out enzymolysis with compound enzyme, carrying out enzyme deactivation, centrifuging, extracting supernatant, desalting with resin, carrying out SephadexG-50 column chromatography, centrifuging, extracting the supernatant, and carrying out freeze drying to obtain the oil camellia seed polypepetide. By adopting the method for extracting the oil camellia seed polypepetide from the oil camellia seed protein, disclosed by the invention, the enzymolysis time is shortened, the energy consumption is reduced, the extraction rate of the oil camellia seed polypepetide is also improved, and the purposes of turning waste into wealth and having low energy consumption and low pollution are achieved.

The invention discloses a preparation method a formaldehyde-free protein-based wood adhesive. According to the invention, fresh plant stems and leaves are added into water, and are crushed and press-filtrated, such that a juice is obtained; soybean meal and separated animal protein or separated vegetable protein are sieved by using a sieve of 60 to 300 meshes; the meshed materials are stirred with water according to a ratio of 0-1:1-0:5-15, until a crude protein content of the mixture is 7 to 20%; the mixture is placed in a reactor, and is stirred for 30min to 5h under a temperature of 45 to 65 DEG C and a pH value of 8.5 to 13.5, such that the mixture is subject to a reaction; when the temperature is reduced to 35 to 45 DEG C, the fresh plant stem and leaf juice obtained through the press-filtration step is added to the mixture of protein and water while stirring, wherein the juice takes 0.1% to 50% of the weight of the mixture; the content of adhesive mass crude protein is controlled, that when the adhesive is used in a plywood, the content is 11 to 13%, and when the adhesive is used in a fiber board, the content is 5 to 7%; the pH value of the material is regulated to 7.5 to 10.5, and the material is stirred for 15 to 45min; 0.00 to 0.50% of a preservative is added, and polyphenol is blended. The adhesive provided by the invention is not polluted by free formaldehyde, volatile phenols, isocyanate or synthetic resin. A conflict of protein denaturation and hydrolysis can be regulated by using a heat denaturation technology. When denaturation is finished, the reaction temperature and the pH value can be reduced instantly. With the invention, the produced artificial plates satisfy an international standard of II grade plates. After the plates are boiled for 4 hours by boiled water with a temperature of 100 DEG C, adhesive failure is not occurred.

The invention discloses a preparation method for active collagen from compound protease. The method comprises the following steps: 1) adding compound protease into pretreated fish skin mixed liquor for enzymatic hydrolysis, wherein the compound protease at least comprises two selected from the group consisting of papain, bromelain, trypsin, neutral protease, animal protein hydrolase, acidic protease and pepsin; 2) subjecting the obtained enzymatic hydrolysis liquid to centrifugation and taking supernatant; 3) subjecting the supernatant to ultrafiltration and concentration and then to salting-out; and 4) carrying out ultrafiltration, desalination and concentration; wherein the fish skin mixed liquor has a concentration of 2.0 to 8.0 wt% and a pH value of 2 to 6, and the addition amount of the compound protease is 2.0 to 8.0 wt% of the weight of the fish skin mixed liquor. The method provided by the invention has high security and no side-effects; and the prepared active collagen has the advantages of a high extraction rate, high purity, high thermal denaturation temperature and the like.

The invention discloses a production method of pasture fresh milk, comprising the following steps: (1) selecting fresh cow milk; (2) checking and accepting; (3) degassing; (4) clarifying the cow milk; (5) performing standardization; (6) blending, preheating and homogenizing; (7) performing plate-type pasteurization; (8) cooling and homogenizing; (9) performing aseptic packaging. The high-quality fresh milk in an own pasture breeding base is adopted as a base material, so the raw material source is natural and safe; in a production process, before a low temperature heat treatment sterilizing technology is adopted, bovine lactoferricin and a protein protectant are blended for the cow milk, so that the raw material protein heat resistance can be improved, denaturation by heating is not easy to cause, and meanwhile the mouthfeel and flavor of the raw material are improved; the bovine lactoferricin and the protein protectant further have the health efficacy of resisting bacteria and a synergistic effect, destroy nutrient components of the milk at a minimum level, have multiple bactericidal and antibacterial effects, and prolong the shelf life of the milk.

The invention discloses a rapid purification method for recombinant pyrolytic enzyme. According to the method, escherichia coli is used as an expression host of recombinant pyrolytic enzyme, the recombinant pyrolytic enzyme is subjected to inducible expression in host cells of escherichia coli, thalli are collected centrifugally, and escherichia coli is broken by heating to release expressed pyrolytic enzyme; meanwhile, host protein of escherichia coli is denatured, devitalized and precipitated at high temperature, which is favorable for purifying pyrolytic enzyme resisting to thermal denaturation; further, high-purity pyrolytic enzyme is obtained rapidly through the process of bacteria debris catching and protein concentration of pyrolytic enzyme through ultra-filtration. The rapid purification method is easy to operate; the escherichia coli protein thermal denaturation removal rate is high; the purification concentration efficiency is high; the method is adaptable to industrial production and marketing promotion and application.

The invention discloses a grassland roasted lamb leg and a method for making same. The method for making the grassland roasted lamb leg comprises the steps of pre-treating the lamb leg, boiling with special components, roasting, cooling, sterilizing, baking and packaging. Because the lamb leg is boiled with special component, is roasted and is sterilized by rapidly increasing temperature stage by stage through consuming the least heat without overheating the lamb leg, the quality guarantee period of the grassland roasted lamb leg can be ensured, the nutrients of the lamb leg can not be lost due to overheating, and the thermal injury and denaturation of the grassland roasted lamb leg can be reduced. The grassland roasted lamb leg which is traditional food can be industrially produced on a large scale, keeps the traditional taste and nutrients and does not need to be processed on the spot so that the time and the labor are saved.

The invention discloses collagen and an extraction method thereof. The method includes the steps: 1) refrigerating and rubbing animal tissues containing the collagen in liquid nitrogen; 2) extractingthe collagen from the rubbed animal tissues by an acid/enzyme method to obtain collagen solution; 3) dialyzing and freeze-drying the collagen solution to obtain the powdery collagen. By the refrigeration-rubbing pretreatment method, the animal tissues containing the collagen is refrigerated in the liquid nitrogen in advance for a period of time and rubbed into powder under a certain frequency by arubbing instrument, a triple-helical structure and thermal denaturation temperature cannot be affected after treatment by the method, compared with an original acid-extraction method without refrigeration-rubbing, the extraction rate of the method is increased by 18%-82%, and the method is of great significance for application of the collagen and collagen-based biological materials.

The invention relates to an antibacterial antioxidant whey protein isolate edible film and a preparation method thereof, and belongs to the technical field of food packaging. The whey protein isolateedible film is prepared by taking whey protein isolate as a main film-forming matrix, matching the whey protein isolate with a bamboo leaf antioxidant and sodium caseinate, adding a plasticizer, and performing the steps of uniform mixing, thermal denaturation, vacuum degassing, plate casting, drying, film uncovering and the like. The method is simple in process, the prepared whey protein isolate edible film is good in stretchability and high in strength, has the advantages of being low in moisture permeability, good in transparency, antibacterial and antioxidant, the shelf life of food can beeffectively prolonged, and the requirement for food packaging is met.

The invention discloses a desalination method for salted egg white, and the method is simple in technology, low in equipment requirement and high in desalination efficiency. The method is characterized by in that the method comprises steps of performing protein heat denaturation on salted egg white and performing water-washing immersion desalination on salted-egg-white protein; a coagulum prepared by desalinating salted egg white is crushed by a colloid mill and is enzymolyzed, the enzymolysis solution is subjected to condensation and spray drying, so that the salted-egg-white protein peptide powder is obtained. The salted-egg-white protein peptide powder does not have bitter taste, the freshness is same to that of a monosodium glutamate solution with the concentration of 0.5%, the protein recovery rate is 92% or more, the physical and chemical indexes of the salted-egg-white protein peptide powder accord with GB/T 22492-2008 standard requirements, and the peptide content is detected to be 70% or more according to GB/T 22493-2008 standard. The technology is simple, desalination efficiency is high, desalination rate reaches 96% or more, an asynchronous enzymolysis manner of papain and flavourzyme is employed when enzymolysis is performed, and the enzyme killing technology and the condensation technology of the enzymolysis solution are synchronously performed, the technology is simple, and the produced salted-egg-white protein peptide powder is good in quality, safe and reliable to eat, and is widely applicable to various nutrient food, health-care beverages and cakes.

The invention relates to a production method for a recombinant humanized superoxide dismutase and belongs to the bioengineering technology field. In the method, most of impure proteins are removed by utilization of copper salt heat denaturation; after centrifugation, bacteria and impurities are removed by microfiltration; concentration is carried out by utilization of ultrafiltration, salts and micromolecule impure proteins are removed; after anion exchange chromatographic purification, freeze drying is carried out. The purity of the superoxide dismutase can reach 92%, and the activity is 3170U/mg. During the separation process, no organic solvents are used, and protein denaturation caused by organic solvents is avoided. The method has simple operation and low cost, and is suitable for industrial production.

The invention discloses a production method of a Sacha inchi polypeptide. The method uses the properties that Sacha inchi protein has different solubility under different conditions and can be subjected enzymatic hydrolysis by protease, and that ultrafiltration membrane and nanofiltration membrane have different retention rate on substances with different molecular weights. The method is as below: extracting protein from Sacha inchi meal by water, separating Sacha inchi pomace, and conducting ultrafiltration on the aqueous extract to remove impurities to obtain purified water extract; mixing and heating Sacha inchi pomace and purified water extract for denaturation; conducting enzymatic hydrolysis, enzyme inactivation and separation to obtain a Sacha inchi polypeptide solution; conducting ultrafiltration impurity removal and nanofiltration concentration on the Sacha inchi polypeptide solution to obtain a Sacha inchi polypeptide a concentrated liquid; and conducting spray drying on the polypeptide concentrated liquid to obtain Sacha inchi polypeptide. The production method of Sacha inchi polypeptide has the advantages of low cost, high purity, white color, good flavor, edibility, high yield, strong function and mechanization.

The invention relates to a method for extracting CEL I nuclease in celery and discards measures adopting a plurality of high-speed or ultra-speed centrifugation and a plurality of gel filtration and ion exchange chromatography in the prior art. The method comprises the following steps: adding a small amount of sodium sulfite to extract so as to reduce and clear colored substances in the extract; adopting a thermal denaturation physical method to rapidly clear a great amount of foreign protein with poor temperature toleration; utilizing the characteristic that CEL I is the combination of glycoprotein and activated concanavalin to combine CEL I nuclease and concanavalin so as to remove the foreign protein and further purify the CEL I; and finally, selecting DEAE-Sepharose FF as a suitable medium for the CEL I by once chromatography purification. Accordingly, the extraction method replaces the time-consuming and expensive measures adopting a plurality of high-speed even ultra-speed refrigerated centrifugation, a plurality of gel filtration and ion exchange chromatography, and the like and achieves the aims that the CEL I nuclease is rapidly extracted from the celery and purified.

The invention relates to a making method of instant nutritional vegetable bean curd. The method comprises the following steps: preparing vegetable granules; preparing soybean milk; preparing bittern; boiling soybean milk, comprising: carrying out low temperature boiling on the prepared soybean milk, heating to 80DEG C in the boiling process, and carrying out heat insulation for 5min in order to carry out protein heat denaturation treatment; adding glucose accounting for 1% of the mass of the soybean milk when the temperature rises to 100DEG C, boiling for 10min to carry out glycosylation crosslinking polymerization, cooling to 80DEG C, and adding the prepared vegetable grains into the boiled soybean milk; adding the bittern to make bean curd; seasoning; compacting; and packaging to obtain the instant nutritional vegetable bean curd. Vegetable bean curd products with the characteristics of abundant nutrition, good color and taste, convenience and fastness can be directly made by adopting the making method, and the bean curd products have the advantages of good hardness, fine texture, good elasticity, unbreakable property and substantially improved mouthfeel. Determination results show that the protein content, the fat content and the vegetable content of the instant nutritional vegetable bean curd are greater than 16%, greater than 9% and greater than 5% respectively.

The invention provides a water cooling mold for low-pressure casting of an aluminum alloy wheel. The water cooling side mold comprises an upper mold, a lower mold and side molds, wherein the upper mold, the lower mold and the side molds form an aluminum alloy cavity, a cooling insert is arranged into side mold frames of the side molds, an upper parting surface, a lower parting surface and side parting surfaces of the cooling insert are in contact segmentation with the side mold frames, and the side parting surfaces comprise front part areas and rear part straight section areas, and gaps of 1.5-2.5 mm are formed between the rear straight section areas and the side mold frames. A cooling water channel is designed in a straight channel mode, so that the temperature difference between the center and the two sides of the side molds is balanced, and the heat denaturation of the mold is reduced; the air permeability of the mold is improved; the cooling range of the side molds can be further controlled through the cooperative use of blind holes and a through hole heat insulation groove; and the service life of the mold can be prolonged, and the cost of the mold can be reduced.