72 results about "Polyphenol oxidase" patented technology

The invention discloses a method for inhibiting browning of apple juice through combination of ultrahigh pressure and medicinal and edible substances, and belongs to the technical field of fruit processing. In order to solve the problems of color deterioration, nutrition loss and flavor loss caused by enzymatic browning in the processing and storage processes of non-concentrated and reduced apple juice, the technical scheme is characterized in that fresh apples, gastrodia elata and phyllanthus emblica are respectively prepared into juice, gastrodia elata juice and phyllanthus emblica juice are added into the apple juice according to a ratio, and the juice is added into the apple juice according to a ratio. The raw materials are stirred, mixed, packaged and packaged, then subjected to ultrahigh pressure treatment with specific parameters at a constant temperature, and finally subjected to low-temperature storage. The preparation method can effectively inhibit the activity of polyphenol oxidase and peroxidase, delay the browning process and remarkably improve the oxidation resistance of fruit juice, and is mainly used for quality maintenance and browning inhibition of natural and additive-free apple juice and other fruit and vegetable juice.

The present application provides an application of inhibiting or knocking out tobacco polyphenol oxidase gene NtPPO12 in inhibiting tobacco browning. The present application screens an important gene NtPPO12 related to tobacco browning through transcriptome sequencing and molecular biology experiments, further verifies the promoter activity and gene expression site of NtPPO12, and deeply researches the function of the gene through gene editing and overexpression. The present application proves by molecular biology experiments that the NtPPO12 gene provided by the present application is a key gene related to browning in the mature curing process of tobacco, and by regulating the expression amount of the NtPPO12 gene, the browning degree of tobacco can be controlled, and the tobacco maturity and curing resistance can be improved, which is beneficial to reducing the picking frequency, improving the curing characteristics, and improving the appearance and internal quality of tobacco leaves, so it has a broad market application prospect.

The application discloses a kind of high-activity polyphenol oxidase and preparation method thereof, belong to nano mimic enzyme synthesis technical field.The polyphenol oxidase of the application is with copper ion as active center, 2-methyl imidazole and guanylate disodium as organic ligand.Preparation method thereof includes the following steps: guanylate disodium solution is added to copper chloride solution under stirring condition, to obtain first mixed solution;First mixed solution is slowly added to 2-methyl imidazole solution under stirring condition, to obtain second mixed solution;Second mixed solution is centrifuged after ultrasonic at room temperature, to obtain brown precipitate, and the polyphenol oxidase is prepared by washing and drying brown precipitate.The mimic enzyme prepared by the application has higher catalytic performance, better stability and feasibility of large-scale preparation compared with natural enzyme, and will have broad application prospect in the field of biosensor.

The invention provides a cooking method and device, a readable storage medium and cooking equipment. The cooking method is applied to the cooking equipment, and the cooking method comprises the following steps: on the basis that the cooking temperature in a cooking cavity is within a first temperature range and lasts for a first duration, stopping heating the cooking cavity; on the basis that the cooking temperature is lowered to a first temperature threshold value, the cooking cavity is heated, so that the cooking temperature is within a second temperature range; and heating the cooking cavity until the target liquid in the cooking cavity is in a boiling state on the basis that the cooking temperature is within a second temperature range and lasts for a second duration. According to the method, oxidation of polyphenol oxidase in the food materials on polyphenol nutritional ingredients is reduced, loss of the polyphenol nutritional ingredients caused by the high cooking temperature is reduced, and the content of the polyphenol nutritional ingredients in the cooked food is further increased.

The present application relates to asparagus tissue culture technical field, specifically to a kind of asparagus tissue culture rapid propagation seedling cultivation method.A kind of asparagus tissue culture rapid propagation seedling cultivation method, comprising: the disinfection and browning prevention treatment of explant, preparation of composite antibacterial agent, preparation of culture medium, asparagus explant culture and transplanting.The present application adopts ozone fumigation to combine ultraviolet light disinfection, synergistic sterilization, covers surface and deep layer, reduces explant injury and browning.Browning prevention agent inhibits polyphenol oxidase, removes free radicals, reduces browning, promotes axillary bud germination.Add composite antibacterial agent in induction culture medium, destroys microbial cell membrane, has antibacterial and antioxidant effects, and guarantees explant growth.Compound rooting agent contains activated carbon, chitosan and sucrose, adsorbs harmful substances, stimulates root differentiation and provides energy, improves rooting rate and plant robustness.Overall, it improves the success rate of asparagus tissue culture.

Compositions and methods for the production of L-glufosinate are provided. The method involves converting racemic glufosinate to the L-glufosinate enantiomer or converting PPO to L-glufosinate in an efficient manner. In particular, the method involves the specific amination of PPO to L-glufosinate, using L-glutamate, racemic glutamate, or another amine source as an amine donor. PPO can be obtained by the oxidative deamination of D-glufosinate to PRO (2-oxo-4-(hydroxy (methyl) phosphinoyl) butyric acid) or generated via chemical synthesis. PPO is then converted to L-glufosinate using a transaminase in the presence of an amine donor. When the amine donor donates an amine to PPO. L-glufosinate and a reaction by product are formed. Because the PPO remaining represents a yield loss of L-glufosinate, it is desirable to minimize the amount of PPO remaining in the reaction mixture. Degradation, other chemical modification, extraction, sequestration, binding, or other methods to reduce the effective concentration of the by-product. i.e., the corresponding alpha ketoacid or ketone to the chosen amine donor will shift the reaction equilibrium toward L-glufosinate, thereby reducing the amount of PPO and increasing the yield of L-glufosinate. Therefore, the methods described herein involve the conversion or elimination of the alpha ketoacid or ketone by-product to another product to shift the equilibrium towards L-glufosinate.

The invention discloses application of pseudopenicillin variotii in preparation of a resistance inducer for preventing and treating plant diseases, and belongs to the technical field of plant protection. The invention provides an application of Panax variotii in prevention and treatment of plant diseases, the application concentration of the Panax variotii is 0.1 microgram / mL-1 microgram / mL, a plant resistance inducer containing the Panax variotii can be sprayed on plant leaves or fruit surfaces and has a remarkable prevention effect on anthrax leaf blight, and the higher the concentration is, the better the prevention effect is; the pseudopenicillin variotii can promote synthesis or activity improvement of catalase, peroxidase, polyphenol oxidase, glutathione S-transferase and superoxide dismutase in apple bodies, and also can remarkably induce up-regulation expression of disease-resistant related genes such as MdPR2 and MdPR5, so that the disease resistance, the antioxidant level and the plant immunity of apples are enhanced; a novel and efficient plant resistance inducer application scheme is provided for apple disease control and physiological regulation.

The invention belongs to the field of crop heredity, and relates to application of a polyphenol oxidase gene. The invention discloses an InDel marker for rice brown glume traits, a regulatory gene and application of the InDel marker and the regulatory gene. Based on a brown glume mutant material in the background of Hunan early indica 42, genetic analysis shows that the mutation is dominant mutation, single-gene control and gene positioning find that the mutant gene is a polyphenol oxidase encoding gene (MSULocus is LOCOs04g53300), and the exon region of the mutant gene is deleted by 6bp (GCGACT), so that the material shows brown glume; the gene is knocked out from a brown glume mutant, and the glume color becomes normal; the method has the advantages that the GCGACTs are used as the raw materials, the GCGACTs are accurately edited in the wild type materials, the corresponding 6bp deletion (GCGACT) materials are obtained, the glumes of the GCGACTs are brown, and new gene resources and methods are provided for quickly and directionally cultivating novel rice materials and rice materials suitable for mechanized seed production of hybrid rice.

The invention relates to the technical field of seasoning sauce preparation, in particular to a composite enzymatic hydrolysis aroma enhancement preparation method of seasoning sauce, which comprises the following steps: soaking shiitake mushroom particles in a composite buffer solution to obtain a solid A and a flavor liquid B, mixing the solid A with deionized water, grinding into a homogenate, performing three times of enzymatic hydrolysis to obtain an enzymatic hydrolysate C, and adding the sterilized supernate D, the solid A and the flavor liquid B into other stir-fried raw materials to obtain the seasoning sauce with obvious shiitake mushroom flavor and sufficient fragrance. Cellulase in the composite buffer solution can quickly decompose a cellulose skeleton of a cell wall, so that polyphenol oxidase can enter cells conveniently, an enzymatic browning reaction is catalyzed, a Maillard reaction is facilitated, and various flavor substances are generated; and after the three-step enzymolysis reaction, protein in the shiitake mushrooms is hydrolyzed into small molecular amino acids, so that the fresh and sweet flavor is effectively increased, the shiitake mushroom flavor is more obvious, and the method has a wide application prospect.

The application discloses application of NtPPO7 gene in regulating chlorogenic acid content in tobacco leaves and tobacco variety cultivation, and belongs to the technical field of plant genetic engineering. The cDNA of leaves of common tobacco at different periods is used as a template, and a homologous gene of polyphenol oxidase of tobacco is cloned by using PCR technology, and is named as NtPPO7. It is found through cloning of the NtPPO7 gene and construction and analysis of an expression vector that overexpression of the gene in tobacco plants can significantly reduce the content of chlorogenic acid in mature tobacco leaves, which indicates that the NtPPO7 gene has an important role in regulation of chlorogenic acid in mature tobacco leaves. The application enriches the polyphenol oxidase gene family of tobacco, and lays a foundation for in-depth study of the polyphenol oxidase gene family in tobacco. Meanwhile, the application lays a foundation for elucidating a molecular regulation mechanism of chlorogenic acid biosynthesis in tobacco leaves, and provides a new precise regulation gene for regulation of the content of chlorogenic acid in tobacco leaves.

The invention relates to the technical field of tea processing, in particular to a black tea fermentation regulation and control method and equipment based on a multienzyme synergistic effect, and the method comprises the following steps: S1, mixing enzymes such as polyphenol oxidase and peroxidase, adding trehalose, trisodium citrate and vitamin C, fixing the volume with a phosphate buffer solution, and activating in a water bath at 30 DEG C to obtain a compound enzyme solution; s2, withering the fresh leaves until the water content is 60-65%, performing UV-C intermittent irradiation, and performing gradient rolling to obtain rolled leaves; s3, spraying enzyme liquid which accounts for 1.5-2.0% of the weight of the rolled leaves, and performing ultrasonic-assisted permeation; s4, performing three-stage temperature-controlled fermentation, stirring every 30 minutes, introducing ozone air, and adding a pulsed magnetic field every hour; s5, detecting the conversion rate of tea polyphenol, theaflavin and the like, and terminating fermentation after reaching the standard; s6, performing microwave fixation after hot air treatment; and S7, drying in sections until the water content is 5-6% to obtain a finished product. According to the method, the tea polyphenol conversion efficiency and theaflavin generation balance of the black tea are improved, aroma substances are reserved, and the functional activity is enhanced; the process stability is optimized, the energy consumption and pollution are reduced, and the black tea quality and industrial benefits are improved.

The invention provides a tea leaf freezing, withering and rolling process parameter determination method and a preparation method, relates to the technical field of tea leaf preparation, and aims to solve the problem of poor tea leaf quality caused by non-uniform withering and finished product appearance in a traditional process. According to the method, a technological parameter control algorithm is introduced, key technological parameters are subjected to collaborative optimization, the phenomenon of traditional uneven withering is improved, and the identifiability of a three-technological-parameter coupling relation is improved, so that the rapid contact reaction of polyphenol compounds and polyphenol oxidase is promoted, and the tea quality is effectively improved. The optimal key process parameters determined on the basis of the method are applied to the preparation process of the pointed Taiping Kui black tea, the effective index content and withering uniformity can be remarkably improved, the tea strip forming rate and moderate overflow of tea juice are ensured to support flavor formation, and the parameters of each step are controllable to ensure the stable quality of a finished product.

This invention discloses tobacco polyphenol oxidase NtPPO6, its encoding gene, gene editing vector, and applications. The nucleotide sequence of the tobacco polyphenol oxidase encoding gene NtPPO6 of this invention is: (1) the nucleotide sequence shown in SEQ ID NO.1; or (2) the nucleotide sequence shown in SEQ ID NO.1, after substitution and / or deletion and / or addition of one or more nucleotides, expressing a protein with the same function. Detection revealed that knocking out the NtPPO6 gene in tobacco significantly reduces the activity of polyphenol oxidase in tobacco plants and increases the chlorogenic acid content in tobacco plants; moreover, tobacco plants with the NtPPO6 gene knocked out show increased plant height, reduced average leaf size, and increased maximum leaf width in the middle, width of the top leaf, and length of the top leaf.

The invention belongs to the technical field of intelligent food packaging films, and particularly relates to a preparation method and application of a biomass-based active packaging film. According to the film, a double-network skeleton is constructed by using wood nano cellulose / sodium alginate, so that the film is endowed with excellent flexibility, ultraviolet shielding property and antibacterial activity; furthermore, zein nanoparticles loaded with curcumin are uniformly embedded into the matrix, so that ammonia-sensitive color development and curcumin slow release synergism are realized. Due to the introduction of the curcumin-zein nanoparticles, the mechanical strength, the water-oxygen barrier property, the oxidation resistance and the antibacterial property of the film are further remarkably improved, and reversible color change occurs in the presence of NH3, so that the meat product decay visual detection is realized. Fresh shrimps are packaged with the film and stored at 4 DEG C, the activity of polyphenol oxidase can be remarkably inhibited, blackening and microbial proliferation are delayed, and a green, visible and controllable multifunctional packaging strategy is provided for a meat supply chain.

The application belongs to the technical field of biological fermentation, and relates to a bacillus subtilis SXZY-03 and application of the bacillus subtilis SXZY-03 in tobacco leaf fermentation. Bacillus subtilis The bacillus subtilis SXZY-03 is separated from the surface of tobacco leaves (CCTCC NO: M 2025150), and the strain is fermented to prepare a biological preparation containing the bacillus subtilis SXZY-03; after activation and concentration optimization of copper sulfate, manganese sulfate and ferric sulfate, polyphenol oxidase enzyme activities reach 112.59, 69.26 and 51.26 U·mL ‑1 respectively; the biological preparation is applied to tobacco shred fermentation, polyphenols are degraded, tobacco aroma quality is effectively improved, irritation is reduced, and aftertaste is improved. The technology provides a green and environment-friendly solution for tobacco quality upgrading, and meets the high-quality development direction of the industry.

The invention discloses an efficient and universal tissue culture anti-browning method for sugarcane plants, and belongs to the technical field of tissue culture. According to the invention, the potassium cinnamate is used as an anti-browning active substance for the first time and is used in plant tissue culture pretreatment and induction culture treatment, and a synergistic strategy of low-temperature pretreatment, explant potassium cinnamate soaking and culture medium addition is introduced, so that a remarkable beneficial effect is achieved in sugarcane plant tissue culture anti-browning. Through synergistic application of low-temperature pretreatment and potassium cinnamate, the activity of polyphenol oxidase is inhibited in a targeted manner, and browning is effectively blocked. According to the method, the browning rate of different germplasm sugarcane plants is remarkably reduced, the regeneration efficiency is synchronously improved, the genotype dependence of a traditional browning resisting technology is successfully overcome, and an efficient and universal solution is provided for development and utilization of sugarcane germplasm resources.

The invention provides a multi-product comprehensive preparation method based on potatoes and products thereof, and belongs to the technical field of deep processing of the potatoes, the preparation method comprises the following steps: firstly, washing the potatoes, peeling, and cutting into small blocks to obtain blocky potatoes; soaking the blocky potatoes in a citric acid solution for color protection treatment to obtain a solid-liquid mixed material; crushing the blocky potatoes in the solid-liquid mixed material, so that the potato blocks are always in an acidic reducing environment in the crushing process to inhibit the activity of polyphenol oxidase, and filtering to obtain coarse potato filter residues and raw potato juice; then carrying out centrifugal treatment on the raw potato juice, and collecting to obtain a bottom precipitate and a nutritional supernatant; and drying the potato coarse filter residue and the bottom precipitate to obtain a potato raw whole powder product, and sterilizing the nutritional supernatant to obtain a potato beverage product.

The application discloses a cassava tuber postharvest browning inhibition and fresh storage quality preservation treatment method, which comprises a three-step synergistic process of polyphenol oxidase targeted inhibition pretreatment, selective air permeable composite coating treatment and biological antagonistic bacteria surface inoculation treatment. First, the tuber is immersed in a vacuum infiltration treatment of a citric acid and L-cysteine hydrochloride composite inhibition solution, then is immersed and coated with a chitosan-sodium alginate-nano silicon dioxide selective air permeable composite coating, and finally is sprayed with bacillus subtilis inoculation. The three-step treatment synergistically realizes vascular browning inhibition for 25-30 days, and prolongs the shelf life from 2-3 days to 3-4 weeks.

This invention discloses a method for preparing high-astragalus-content dried apples using a cyclic steaming and drying process, belonging to the field of food processing technology. Through a three-stage cyclic steaming and drying process involving three steaming cycles and three low-temperature drying cycles, combined with the steam explosion effect, pores are formed within the apple tissue. This allows the water-soluble component of astragalus, astragalus polysaccharide, and some fat-soluble component astragaloside A in astragalus to be continuously released under the action of warm steam. This promotes the rapid absorption of the water-soluble components of astragalus polysaccharide and some fat-soluble components of astragaloside A by the dried apples, which diffuse with the moisture, thus simultaneously increasing the content of astragalus polysaccharide and astragaloside A in the dried apples. Furthermore, by pre-soaking apple slices in a color-protecting solution and a preservative coating solution, and then combining this with the three-stage cyclic steaming and drying process, the polyphenol oxidase in the apples is deactivated by the hot steam, effectively preventing browning.

The present invention provides isolated DNA molecule(s), isolated polypeptide(s), artificial vector(s), and cell(s) including same. Further provided are methods for increasing the amount of an amino acid, as well as for synthesizing L-DOPA including a derivative thereof.

The invention provides a disinfection method of a ginseng explant, which comprises the following steps: soaking and disinfecting the ginseng explant by using a chemical disinfectant, soaking the soaked and disinfected explant into a first ethanol solution, taking out, igniting residual ethanol on the surface of the explant, burning, and cooling. According to the method disclosed by the invention, conventional chemical disinfection and high-concentration ethanol infiltration-flame burning are creatively combined, and the step-by-step and synergistic sterilization strategy is particularly suitable for explants with complicated structures, such as ginseng roots. Compared with a traditional disinfection method needing long-time soaking and multiple times of rinsing, the method has the advantages that the total disinfection time is greatly shortened and the explant preparation efficiency is remarkably improved by introducing an instantaneous firing step, and the explant preparation efficiency is greatly improved by reducing the total contact time of a chemical disinfectant, inactivating surface polyphenol oxidase by utilizing instantaneous high temperature and combining rapid cooling. The browning reaction is effectively inhibited, and the activity of the explant is ensured.

The application discloses a strain of Lecythophora ramosa LicG6 and application of the strain in solid-state fermentation of Pu'er tea, and belongs to the field of industrial microbial resource development and tea deep processing technology. The Lecythophora ramosa LicG6 is preserved in the China General Microbiological Culture Collection Center on June 14, 2024, and the address is No. 1, Xibei Road, Chaoyang District, Beijing, and the preservation number is CGMCC No. 41370. The application inoculates the Lecythophora ramosa LicG6 strain with double-enzyme synchronous secretion capacity, namely, simultaneously high expression of beta-glucosidase and polyphenol oxidase, into a solid-state fermentation system of Pu'er tea, realizes flower fragrance development by continuously hydrolyzing and releasing glycoside aroma precursor driven by beta-glucosidase under the condition of temperature control in stages, realizes red soup color transformation by oxidizing and polymerizing catechin driven by polyphenol oxidase, and thus, the two quality targets of "flavor enhancement" and "color transformation" are achieved simultaneously in the same fermentation process.

The application discloses an insect pathogenic preparation for preventing and treating Cylas formicarius, a preparation method and application thereof, and belongs to the field of agricultural technology. The insect pathogenic preparation for preventing and treating Cylas formicarius comprises a corpse compound agent of an insect pathogenic nematode and a sweet potato root protection agent. The corpse compound agent of the insect pathogenic nematode comprises an insect pathogenic nematode corpse agent, an artificial feed of Cylas formicarius, a polyphenol oxidase inhibitor and trehalose (alpha,alpha) dry powder, and the mass ratio is 1-3:6-8:0.25-0.35:0.6-0.8. Each 1L of the sweet potato root protection agent contains 0.03-0.05g of a biocontrol bacterium agent, 3-5g of a Cylas formicarius repellent and 90-110ml of a bonding agent, and the volume is supplemented with water. The application further discloses a preparation method of the insect pathogenic preparation and application thereof in preventing and treating Cylas formicarius. The insect pathogenic preparation can prevent and treat Cylas formicarius through multiple actions, and has a good prevention and treatment effect on adult and larva of Cylas formicarius.

This invention discloses an in-situ tyrosinase sensor based on a carbon quantum dot microneedle composite structure, its preparation method, and its application. Carbon quantum dots (Cate-CQDs) with surface-modified catechol groups were synthesized using urea, anhydrous citric acid, and catechol as raw materials. The Cate-CQDs were uniformly dispersed in a hydrogel and then fixed inside the microneedles after drying. When the microneedles pierce the target skin containing TYR, due to the polyphenol oxidase properties of TYR, catechol is specifically oxidized to benzoquinone by TYR, quenching the original fluorescence of the Cate-CQDs. This invention uses Cate-CQDs as a probe, possessing sensitive tyrosinase detection capabilities and resisting interference from common amino acids and proteases. Compared to small molecule fluorescent probes, carbon quantum dots exhibit stronger resistance to photobleaching. With a fluorescence detection limit as low as 0.052 U / mL and a colorimetric detection limit of 0.10 U / mL, and a linear range covering 0.5–100 U / mL, it can complete the detection within 30 minutes and is suitable for rapid analysis of tyrosinase concentrations in the skin or other matrices.

The invention provides a notopterygium root complex microbial inoculant with excellent shape and high quality and a use method thereof, and belongs to the technical field of plant cultivation. The invention provides a complex microbial inoculant for inhibiting the formation of lateral roots of notopterygium seedlings, which comprises Witzia ciliaris and Brevibacillus laterosporus. The complex microbial inoculant is mainly used for reducing the content of 1-aminocyclopropane-1-carboxylic acid (on the premise of ethylene synthesis) and the content of ICA (Indoleacetic Acid) (auxin) by increasing the content of salicylic acid; the activity of peroxidase and glutamine synthetase and the content of total phenols in plants are improved; the contents of soil urease, polyphenol oxidase and alkali-hydrolyzable nitrogen are increased, and the contents of rapidly available potassium and total phenolic acid are reduced; and ammonium nitrogen is promoted to be converted into nitrate nitrogen, so that the generation of lateral roots of the notopterygium roots is inhibited, the nitrogen content of seedlings of the notopterygium roots is increased, the disease resistance is improved, and the breeding of excellent-shape and high-quality seedlings is promoted.

An intelligent preservation control system for a refrigerated transport warehouse, belonging to the field of refrigerated transport warehouses, includes a refrigeration unit, a humidification unit, a hydroxyl-based sterilization and disinfection unit, a respiration suppression unit, a data acquisition unit, a control unit, a storage unit, and a remote terminal. This invention constructs an IoT-based intelligent sensing and monitoring system covering the entire equipment process. Through IoT technology, it monitors the fruit and vegetable storage environment in real time, achieving real-time monitoring of the equipment and ensuring stable quality. This invention also develops an intelligent application system that intervenes and controls the release of ethylene within the product by controlling temperature, humidity, oxygen content, carbon dioxide content, and environmental microorganisms, inhibiting the effects of pectinase, cellulase, and polyphenol oxidase on the product, ensuring product quality, achieving the goal of long-term product preservation, and realizing precise environmental control during product transportation and storage.

The invention belongs to the field of food processing, and relates to a response surface method optimized tarragon color protection treatment process which comprises the following steps: S1, blanching fresh tarragon to be processed; s2, cooling the blanched artemisia dracunculata, and putting the cooled artemisia dracunculata into a color protection solution for soaking treatment; the color protection liquid comprises citric acid, ascorbic acid, calcium chloride and water. And S3, draining the artemisia dracunculata subjected to the soaking treatment. The blanching treatment can significantly inhibit the activity of polyphenol oxidase in the tarragon, further inhibits the leaf browning of the tarragon, and prolongs the green value of the tarragon. The green color of the tarragon can tend to be deepened by soaking the tarragon in the color protection liquid, the loss of chlorophyll in the tarragon can be reduced by the color protection liquid, and meanwhile, the activity of polyphenol oxidase is reduced.

The invention discloses a method for inhibiting browning of calluses of woody plants, and belongs to the technical field of plant tissue culture. Aiming at multi-factor inducements of enzymatic browning, a multi-level synergistic intervention strategy is adopted, and the method mainly comprises the following steps: (1) introducing a double-chelation working solution for specifically inhibiting the activity of polyphenol oxidase and peroxidase and a bidirectional pH response self-buffering microcapsule capable of accurately maintaining the pH value of the culture medium for a long time into an improved DKW culture medium; (2) thoroughly removing condensate water on the surface of a culture medium before inoculation of the explant; and (3) implementing staged temperature regulation and control, and helping the explant to pass through a trauma stress period through initial low-temperature dark culture. According to the method disclosed by the invention, the browning rate of the callus is remarkably reduced, the quality of the callus is improved, and an efficient and stable technical scheme is provided for solving the problem of browning of woody plant tissue culture industrialization.

The invention discloses a processing method for improving the quality of a potato whole powder finished product, and relates to the technical field of potato whole powder preparation. The method solves the problems that in traditional processing, potato cell structures are prone to damage, starch leaks, so that the potato is pink and sticky to teeth after rehydration, polyphenol oxidase causes enzymatic browning, so that the color becomes dark, and the safety risk is caused by chemical color fixative residues. According to the technical scheme, the method comprises the following steps: peeling and slicing potatoes, and carrying out stepped variable-temperature synergistic treatment: firstly, carrying out enzyme activation in a weakly alkaline treatment solution containing pectin methylesterase at 45-50 DEG C to strengthen cell walls, and then, carrying out crosslinking and color protection in a weakly acidic treatment solution containing glucose oxidase and calcium chloride at 15-25 DEG C to replace sulfite; and then drying and grinding at low temperature under the protection of inert gas. The obtained potato whole flour is high in cell integrity, pure white in color and luster and good in reconstitution property, is mainly used for production of potato staple food products such as noodles and steamed buns, and improves the cooking quality and sensory characteristics of terminal products.

Compositions and methods for the production of L-glufosinate are provided. The method involves converting racemic glufosinate to the L-glufosinate enantiomer or converting PPO to L-glufosinate in an efficient manner. In particular, the method involves the specific amination of PPO to L-glufosinate, using L-glutamate, racemic glutamate, or another amine source as an amine donor. PPO can be obtained by the oxidative deamination of D-glufosinate to PPO (2-oxo-4-(hydroxy(methyl)phosphinoyl)butyric acid) or generated via chemical synthesis. PPO is then converted to L-glufosinate using a transaminase in the presence of an amine donor. When the amine donor donates an amine to PPO, L-glufosinate and a reaction by-product are formed. For example, when the amine donor is glutamate (including racemic glutamate or L-glutamate), L-glufosinate and the reaction by-product α-ketoglutarate (KG), also known as oxoglutarate, are produced. Because the PPO remaining represents a yield loss of L-glufosinate, it is desirable to minimize the amount of PPO remaining in the reaction mixture. Degradation, other chemical modification, extraction, sequestration, binding, or other methods to reduce the effective concentration of the by-product, i.e., the corresponding alpha ketoacid or ketone to the chosen amine donor will shift the reaction equilibrium toward L-glufosinate, thereby reducing the amount of PPO and increasing the yield of L-glufosinate.Therefore, the methods described herein involve the conversion or elimination of the alpha ketoacid or ketone by-product to another product to shift the equilibrium towards L-glufosinate.