194 results about "Rutin" patented technology

The invention provides a rutin-modified soybean protein isolate-pectin-genipin nano-particle carrier and a preparation method of the rutin-modified soybean protein isolate-pectin-genipin nano-particle carrier. The preparation method of the nanoparticle carrier comprises the following steps: preparing a soybean protein isolate solution, a soybean protein isolate solution after pH shift, an aqueous solution containing rutin-modified soybean protein isolate and an aqueous solution containing rutin-modified soybean protein isolate-pectin; the aqueous solution contains rutin-modified soy isolate protein-pectin-genipin, the concentration of the genipin is 0.05 mg / mL, and the rutin-modified soy isolate protein-pectin-genipin nano-particle carrier is prepared from the rutin-modified soy isolate protein-pectin-genipin nano-particle carrier. The invention further provides application of the rutin-modified soy isolate protein-pectin-genipin nanoparticle carrier. The rutin-modified soy isolate protein-pectin-genipin nanoparticle carrier is used for sustained release of gastric drugs and targeted release of drugs in small intestines. According to the preparation method disclosed by the invention, a rutin-modified soybean protein isolate-polysaccharide nanoparticle carrier with a shell-core structure can be formed, gastric acid erosion can be effectively resisted, and the rutin-modified soybean protein isolate-polysaccharide nanoparticle carrier is delivered to small intestines in a targeted manner.

The invention discloses a method for converting rutin into quercetin through biological catalysis, and belongs to the technical field of biological catalysis. The method comprises the following steps: mixing rutin and a solvent to obtain a quasi-solid rutin suspension; mixing the paraphlonia plant endogenous enzyme and the quasi-solid rutin suspension for enzymolysis, and then filtering, washing and drying to obtain quercetin; the solvent is methanol with the concentration of 5-50%, ethanol with the concentration of 5-50% or acetone with the concentration of 10-50%. The method is mild in biological catalytic reaction condition, does not generate pollutants such as acid waste liquid, and meets the environmental protection requirement. Efficient conversion of quercetin is realized by adopting a quasi-solid rutin strategy (rutin suspension reaction system), and the problem of substrate solubility limitation is solved. High-purity quercetin can be obtained through simple washing, the product purity is larger than 95%, and food and clinical application can be met.

The application discloses a kind of super tough polyvinyl alcohol composite hydrogel with biological activity and preparation method thereof.The polyvinyl alcohol composite hydrogel refers to that polyvinyl alcohol (PVA) is added into NaOH solution, heated to 90 DEG C, and stirred vigorously for 2 hours, after PVA is completely dissolved, a certain proportion of sodium lignosulfonate (LS) and rutin (RT) powder is added, after sodium lignosulfonate and rutin are completely dissolved, it is air-dried into 0.3~0.5 mm thick film at room temperature, then it is immersed in 20~30 mL 10 wt% NaCl solution and swells for 3~5 hours, to obtain PVA-LS-RT composite hydrogel.The polyvinyl alcohol composite hydrogel prepared by the application has super strong mechanical property, and has higher antibacterial, antioxidant and wound healing capacity, and has good application prospect in wound dressing, artificial cartilage and flexible electronics and other cutting-edge fields.

The invention relates to the technical field of analytical chemistry and food pharmacy detection, in particular to a rutin antioxidant activity colorimetric determination method based on a composite nano enzyme, which comprises the following steps: mixing a to-be-detected sample solution with an ABTS free radical cation working solution to carry out first reaction, so that an antioxidant substance in a sample and ABTS free radical cations are subjected to scavenging reaction; adding the composite nano enzyme, a 3, 3 ', 5, 5'-tetramethyl benzidine solution and a hydrogen peroxide solution into a system after the first reaction is completed, and initiating a second reaction; and measuring the absorbance value of the system after the second reaction under a specific wavelength, comparing the absorbance value with the standard curve obtained through the treatment in the same step, and calculating the antioxidant activity expressed by the equivalent concentration of rutin in the sample to be detected. By optimizing reaction conditions, the method provided by the invention simplifies operation steps and can provide accurate measurement results in a wider concentration range.

The invention discloses a determination method of an Ajowan fruit fingerprint spectrum and the fingerprint spectrum thereof, and relates to the technical field of fingerprint spectrums of medicinal materials. The method comprises the following steps: taking rutin, caffeic acid, rosmarinic acid and p-coumaric acid as reference substances, dissolving the reference substances in a solvent, and fixing the volume to obtain a reference substance solution; the method comprises the following steps: taking different batches of ajowan fruit medicinal materials as test products, adding a solvent into the test products, extracting, filtering, and taking subsequent filtrate to obtain a test product solution; respectively injecting the reference substance solution and the test solution into a liquid chromatograph by utilizing a high performance liquid chromatography, recording a chromatogram, and constructing the fingerprint spectrum of the Ajowan fruit according to the chromatogram; and determining the component content of the test solution through an external standard method according to the chromatogram. According to the method, the quality of the ajowan fruit medicinal material is controlled by adopting a method of combining chemical component content determination and a fingerprint spectrum, so that the effective and comprehensive control on the ajowan fruit medicinal material is realized, and a basis is provided for the quality control standard of the ajowan fruit medicinal material.

The application relates to a method for hydrothermal acid-controlled degradation of mulberry leaf polysaccharide and antioxidant application thereof, and belongs to the technical field of extraction of active ingredients in natural products. The method comprises the following steps: pretreating raw materials, hydrothermally reacting and acid-catalytically treating mulberry leaves, and alcohol-sedimenting, separating and purifying mulberry leaf polysaccharide, so as to obtain mulberry leaf polysaccharide, finally, the antioxidant application of the mulberry leaf polysaccharide is explored, and a theoretical basis is provided for development of mulberry leaf resources. The method can not only obtain mulberry leaf polysaccharide, but also obtain high-value natural active ingredients such as rutin, astragalin, scopoletin and isoquercitrin in the mulberry leaves, is beneficial to development and utilization of the mulberry leaf resources, meets the needs of people's health, and has practical significance and economic value.

The invention discloses a rutin-derived compound as well as a preparation method and application thereof. The rutin-derived compound has the following structural general formula, according to the present invention, the rutin is adopted as the raw material to prepare the rutin derivative through the multi-step reaction, and the research results show that the rutin derivative can provide the uric acid reducing effect in the short time, and the elimination effect on the blood uric acid at the low dose concentration is even superior to the elimination effect on the blood uric acid of the positive drug benzbromarone, such that the high clinical application value is provided; and # imgabs0 #.

The invention relates to the field of cosmetics, in particular to a two-way fermentation method, a litchi processing byproduct fermentation product and cosmetics. Comprising the following steps: inoculating a schizophyllum commune strain into a culture medium for fermentation; the culture medium comprises litchi processing by-products and saccharides; the litchi processing byproducts comprise litchi shells and / or litchi seeds; wherein in the culture medium, the mass ratio of the litchi processing byproducts to the saccharides is (1%-8%): (0.4%-2%). According to the technical scheme, the schizophyllum commune is used as an original strain to ferment the litchi processing byproducts, so that the schizophyllum commune can be promoted to secrete the lyophyllum commune polysaccharide SPG, and the release amount of rutin in the litchi processing byproducts can be effectively increased. Meanwhile, the rutin and the lyophyllum commune polysaccharide SPG are stably combined, and the rutin and the lyophyllum commune polysaccharide SPG can stably exist without additional polyhydric alcohols. The prepared fermentation product rich in SPG and rutin not only has the oxidation resistance of rutin, but also achieves the anti-inflammatory and anti-aging effect.

An object of the present invention is to provide an excellent vascular endothelial function improving agent containing hesperidin and rutin. The present invention includes a vascular endothelial function improving agent containing alpha-glucosyl hesperidin and alpha-glucosyl rutin.

The application discloses a preparation method of a hawthorn extract for cigarettes and application of the hawthorn extract in cigarettes, and the preparation method comprises the following steps: mixing and sterilizing rutin with water; inoculating Pseudomonas acidovorans ZY-03, Bacillus subtilis SMXP-58, Micrococcus ZY02 and Pichia membranacei into culture media respectively to form seed liquids; inoculating the seed liquids of the Pseudomonas acidovorans ZY-03 and the Bacillus subtilis SMXP-58 into the rutin solution to obtain a fermentation product 1; grinding and crushing hawthorn and mixing the hawthorn with water and heating, then filtering and mixing the hawthorn with the fermentation product 1 to obtain a mixed solution; mixing the four seed liquids and inoculating the mixed solution into the mixed solution; after fermentation, the mixed solution is extracted by refluxing with an organic solvent, centrifuged, rotary evaporated, and added with an organic reagent to obtain the hawthorn extract for cigarettes. The rutin and the hawthorn are mixed and fermented by using microorganisms, the fermentation effect is improved, flavonoids such as rutin and macromolecular substances in the hawthorn are degraded and converted into aroma components, and the quality of the hawthorn extract for cigarettes is improved.

The invention discloses application of rutin hydrate in preventing and treating repeated embryo planting failure, and belongs to the technical field of assisted reproduction. It is found for the first time that CD36 is a key membrane protein for lipid transport and uptake of EECs, rutin hydrate competitively inhibits combination of CD36 and natural ligands of CD36, abnormal lipid excessive uptake is remarkably blocked, lipid accumulation and lipid toxicity damage in cells are effectively relieved, and the effect of inhibiting EECs lipid transport and uptake is achieved. And finally, the endometrial receptivity defect related to RIF is reversed, and the embryo adhesion and implantation capability is remarkably improved. Therefore, rutin hydrate provides a brand new strategy for developing targeted therapy drugs for RIF, especially for lipid metabolism disorder type endometrial receptivity badness, and has remarkable clinical application and transformation prospects.

The invention relates to the technical field of biology, in particular to a tobacco Nt4CL9 gene and application thereof. According to the application, tobacco Nt4CL9 is knocked out, and compared with a wild type, the cold stress tolerance of the knocked-out mutant strain is improved, the content of flavonoid substance rutin is obviously increased, and phenolic acid substances are increased; potential support is provided for improvement of tobacco cold stress capacity and tobacco quality, and the method has important practical value in genetic improvement of tobacco important characters and basic research of botany.

The present application relates to a kind of preparation method of Fugunkang composition and its detection method, the preparation method is cut into section, first using red koji and saccharomyces cerevisiae combined fermentation extraction, dregs is extracted with water before boiling, concentrate and extract the fermentation liquor and water, it is obtained.The metabolic function of microorganism is fully utilized, promote the release and absorption of effective components of traditional Chinese medicine in vivo, so as to improve the curative effect of traditional Chinese medicine, reduce the side effect of traditional Chinese medicine.The detection method includes spray agent in just bed, parsnip medicine thin layer identification and the content detection of rutin, hypericin;The thin layer identification can identify just bed and parsnip medicine under the same chromatographic condition, the content detection increases the content detection of hypericin on the basis of original, and the content of rutin and hypericin can be determined simultaneously, save the detection cost, ensure the quality of raw material and finished product.

The invention discloses application of geum aleppicum total triterpenes in treatment of hypertension and a preparation method of the geum aleppicum total triterpenes, the geum aleppicum total triterpenes are obtained by step-by-step extraction and purification of geum aleppicum, and the geum aleppicum total triterpenes comprise bitter raspberry sweet F1, 2-hydroxyl oleanolic acid, 2-hydroxyl ursolic acid, 20beta, 20beta, 20beta, 20beta, 20beta, 20beta, 20beta, 20beta, 20beta The traditional Chinese medicine composition is prepared from the following raw materials in percentage by weight: 28-epoxy-28-hydroxytaxasan-3 beta-ol (taraxane triterpenes), ursolic acid, maslinic acid, rosa multiflora acid and tormentic acid. According to the present invention, the geum aleppicum total triterpenes are extracted and purified from the geum aleppicum step by step, and the geum aleppicum total triterpenes can significantly increase the total cross-sectional area of the vascular bed of the ischemic tissue or organ, such that the low blood pressure can meet the blood perfusion for maintaining the life activity so as to achieve the blood pressure lowering purpose; the compound can be widely applied to the field of hypertension prevention and treatment medicines.

An organic sol-gel nano-composition containing three solid lipid nano-components loaded with phytochemical active ingredients is proposed. Panax notoginseng saponins are extracted from Vietnamese Panax notoginseng. Rutin is extracted from Styphnolobium japonicum in Thai Binh Province, Vietnam, and Ginkgo biloba is extracted from Ginkgo biloba trees. The composition has shown to have low toxicity and great bioavailability. In particular, the composition is effective against local myocardial ischemias and arrhythmias, improves the blood rheology, platelet circulation and antiaggregation, and thrombosis, lowers the blood lipids to a certain limit, and has good effects against atherosclerosis. The composition has an antioxidant effect of preventing free radical damages, and has an effect of enhancing capillary resistance, strengthening the vessel walls that reduces hypertension risks, which accordingly protects the cerebral nerves, prevents strokes, and is also used to recover after strokes and other hemorrhagic diseases for the enhancement effects and reconstruction of the damaged blood vessels.

To provide a collagen-containing composition and a method for producing the same, a collagen-containing composition for addition to foods and drinks, and a collagen odor masking agent and a masking method that enable effective masking of collagen odor.SOLUTION: A collagen-containing composition contains collagen, a steviol glycoside, α-glucosyl rutin, and diethyl succinate and / or diethyl malonate.SELECTED DRAWING: None

The invention relates to the field of natural product extraction, and particularly discloses a method for extracting quercetin from sophora flower bud, which comprises the following steps: crushing dry sophora flower bud; the method comprises the following steps: by taking an ethanol water solution with the concentration of 70-80% v / v as an extraction solvent, carrying out ultrasonic extraction at 50-60 DEG C, and carrying out solid-liquid separation to obtain an extracting solution (I) containing rutin; adding glycosidase into the obtained extracting solution (I), adjusting the pH value to 3.5-5.5, adjusting the temperature to 35-50 DEG C, carrying out an enzymolysis reaction for 2-4 hours, and then carrying out enzyme deactivation; the liquid after enzyme deactivation is concentrated and filtered while being hot at the temperature of 50-60 DEG C, filter residues are washed with 70-80% hot ethyl alcohol, filtrate is combined to obtain a mixed solution, the mixed solution is loaded to a macroporous adsorption resin column, gradient elution is conducted through an ethyl alcohol-water solution with the concentration increasing progressively, target elution fractions containing quercetin are collected, concentration and freeze drying are conducted, and the quercetin is obtained. The quercetin prepared by the method has the advantages of high purity and good yield.

This invention discloses a ternary composite foaming agent of flaxseed protein-fucose-rutin, its preparation method, and its application in meringue cookies. The foaming agent is a non-covalent complex formed by flaxseed protein isolate (FPI), fucoidan (FUC), and rutin (RU) through electrostatic interactions, hydrogen bonds, and hydrophobic interactions, with a mass ratio of FPI:FUC:RU = 1:2:(0.2~0.4). This invention forms a structurally stable composite system through the non-covalent interactions of FPI, FUC, and rutin, achieving a foaming height of 95.69±8.77%. The foam retention rate after 30 minutes is more than double that of natural FPI, and the interfacial tension is reduced to below 25 mN / m, overcoming the shortcomings of poor foaming properties and insufficient stability of single plant proteins. Even after high-temperature baking, the foam retention rate remains above 75%, meeting the processing requirements of meringue cookies.

The invention relates to the technical field of buckwheat noodles, in particular to buckwheat noodles and a preparation method thereof, and the preparation method comprises the following steps: S1, raw material pretreatment; s2, preparing powder; s3, kneading dough; s4, controllable enzymatic conversion curing; s5, step-by-step calendaring molding; s6, performing segmented low-temperature drying; and S7, cutting and packaging. No flour, salt or food additives need to be added, through whole-process technology optimization, industrial stable production of the pure sweet buckwheat noodles is achieved, and the technical blank of preparation of the pure sweet buckwheat additive-free noodles is filled up; meanwhile, through a controllable enzymatic conversion process, the proportion of rutin to quercetin is regulated and controlled under the condition that exogenous components are not added, the nutritional value of the product is improved, and the scheme is different from the scheme that flavone components are regulated and controlled by depending on exogenous addition in the prior art.

The invention discloses an acanthopanax endophytic bacterium DLCWJ13 for producing isofraxidin and rutin and application of the acanthopanax endophytic bacterium DLCWJ13, relates to the field of microorganisms, and aims to solve the problems that when isofraxidin and rutin are obtained through an existing method, the plant resource consumption is large, byproducts are generated, and negative influences exist on the environment. The endophytic bacterium of the acanthopanax senticosus is bacillus subtilis DLCWJ13, the endophytic bacterium of the acanthopanax senticosus is preserved in the China Center for Type Culture Collection, the preservation date is June 4, 2025, and the preservation number is CCTCC NO: M 20251246. A secondary metabolite of the endophytic bacterium DLCWJ13 of the acanthopanax root contains isofraxidin and rutin, and has relatively good antioxidant activity. The method is used for producing isofraxidin and rutin through fermentation and carrying out in-vitro oxidation resistance.

The invention provides a preparation method and application of a dendrobium officinale polysaccharide-rutin graft, and belongs to the technical field of chemical modification of natural polysaccharides. The preparation method comprises the following steps: adding dendrobium candidum polysaccharide into deionized water, heating and dissolving, adding ethanol to obtain a binary solvent system, adding an ascorbic acid solution, a rutin ethanol solution and hydrogen peroxide, uniformly mixing, fully reacting to obtain a grafted crude product solution, concentrating, purifying and drying to obtain the dendrobium candidum polysaccharide-rutin graft with the grafting rate of 100mg / g, the molecular weight of the polypeptide is 15.2 to 35.24 kDa; the compound can inhibit the expression of inflammatory factors such as TNF-alpha, IL-6 and IL-1beta, improve the activity of T-AOC and GPx and improve the increase of liver indexes, and can be applied to the preparation of anti-inflammatory, anti-oxidation and liver protection products.

The present application relates to the technical field of plant extract preparation, and particularly relates to a rutin extraction method. The rutin extraction method provided by the present application extracts rutin from sophora fruitling decoction pieces, and comprises the step of mixing the sophora fruitling decoction pieces with an extraction solvent for extraction. The sophora fruitling decoction pieces are prepared by the method comprising the following steps: after maturation, the sophora fruitling is allowed to rise, and then is subjected to cracking treatment to make the sophora fruitling petal crack; the fine powder passing through a 40-mesh sieve accounts for not more than 25% in mass fraction. Compared with the traditional sophora fruitling processing technology, the sophora fruitling decoction piece preparation method can effectively reduce the loss of rutin, and can significantly improve the leaching efficiency of rutin and reduce the leaching of impurities such as polysaccharides. The rutin extraction method provided by the present application can realize efficient extraction of rutin in sophora fruitling, reduce the dissolution of impurities during extraction, and realize green and efficient industrial production of sophora fruitling-derived rutin.

The invention relates to the technical field of cosmetics or skin external preparations, in particular to a glucosylrutin-vitriol composition containing a supramolecular solvent and preparation and application thereof.The composition is prepared from, by mass, 25%-40% of the supramolecular solvent, 8%-10% of vitriol, 0.01%-0.5% of glucosylrutin, 0.1%-5% of an auxiliary additive, 0.01%-0.05% of an antioxidant, 0.4%-2% of 1, 2-pentanediol, 0.1%-0.5% of 1, 2-pentanediol, 0.1%-0.5% of a stabilizer and the balance water. 0.4-2% of 1, 2-hexanediol and the balance of deionized water; the supramolecular solvent comprises a hydrogen bond donor, a hydrogen bond acceptor and a functional cosolvent, the functional cosolvent comprises a deep eutectic solvent and a bio-based solvent, and the total addition amount of the functional cosolvent is 10-15% of the total mass of the hydrogen bond donor and the hydrogen bond acceptor. By optimizing component selection and matching process design, the composition has the advantages that the skin permeability is obviously improved, and the anti-wrinkle, firming and skin repairing effects are realized.

The present application belongs to the technical field of medicine, and particularly relates to a rutin composition for treating arthritis and a preparation method thereof. The rutin composition for treating arthritis comprises the following active ingredients in parts by weight: rutin 20-25 parts, typhaneoside 10-18 parts, and alisol B 11-acetate 8-15 parts. The rutin in the composition has significant anti-inflammatory and antioxidant effects, and can reduce the inflammatory response of arthritis. The typhaneoside has analgesic and anti-inflammatory properties, and the alisol B 11-acetate has anti-inflammatory and cartilage protection effects. The two components produce a synergistic effect with the rutin, and enhance the therapeutic effect of the composition. The three active ingredients are used in combination, and provide a new scheme for treating arthritis.

The invention provides a hair growth composition or a pharmaceutical composition containing rutin and application of rutin in preparation of the hair growth composition or the pharmaceutical composition. The invention provides application of rutin in improvement of hair growth and prevention of alopecia. The rutin can improve hair growth and prevent alopecia by activating a Wnt / beta-catenin signal channel, promoting proliferation of human dermal papilla cells and promoting growth of hair follicles.

The present application relates to the technical field of health food, and particularly relates to a composition and application thereof in maintaining blood glucose health level. The composition comprises rutin, quercetin, kaempferol and pectin. Experiments show that the composition of the present application significantly reduces the activity of alpha-glucosidase, significantly delays starch digestibility, thereby reduces the postprandial blood glucose level of mice, and the effect is obviously better than that of other flavonoid and pectin compositions. It is shown that the rutin, quercetin, kaempferol and pectin are compounded according to a certain proportion, and obvious synergistic effect is produced. In addition, the composition prepared by the present application reduces the use amount of quercetin, increases the utilization rate of pectin, reduces the production cost, and the raw materials are pure natural, safe and non-toxic, functional, low in cost, and have wide application prospect in the deep processing of starch-based health food.

The application discloses a kind of extraction equipment and method for high-purity rutin, it is related to high-purity rutin extraction technical field, including equipment seat, equipment seat is provided with chromatography extraction mechanism, chromatography extraction mechanism is sequentially arranged from top to bottom by first chromatography column, second chromatography column and third chromatography column, first chromatography column and second chromatography column are connected by first connecting component, second chromatography column and third chromatography column are connected by second connecting component, the chromatography column of three different fillings is used in the application, macroporous adsorption resin filling preliminary enrichment rutin and remove macromolecular impurities, polyamide filling further separates rutin and other flavonoids, silica gel filling is fine purification, the extraction purity of rutin is effectively improved in multi-stage separation process, the flow guide vane of first connecting component and external rotary drive component can accurately adjust solution flow rate and flow direction, and optimize elution effect.

The present invention discloses a method for increasing the rutin content in tartary buckwheat seeds using superheated steam technology. The method comprises the steps of tempering and superheating the whole tartary buckwheat seeds in their shells. This method breaks with the conventional wisdom that high-temperature treatment of tartary buckwheat inevitably leads to flavonoid loss. By utilizing the pressure difference between the inside and outside of the tartary buckwheat hulls caused by high-temperature airflow within a short period of time, the method promotes the migration of rutin from the hulls into the tartary buckwheat seeds. This migration is further accelerated by using water from the tempering process as a transfer medium. This method fully utilizes the nutritional value of the hulls, increases the rutin content in the tartary buckwheat seeds, and thus enhances the nutritional and functional value of the edible portion of the tartary buckwheat.

The invention belongs to the technical field of medicines, and particularly discloses an oral squamous cell carcinoma inhibitor and application thereof. The inhibitor takes rutin as an active component. In-vitro experiments prove that rutin can significantly inhibit proliferation, clone formation, migration and invasion ability of OSCC cells in a dose-dependent manner, and effectively induce cell apoptosis. The action mechanism of the rutin is as follows: the rutin can directly target STAT3 protein and inhibit phosphorylation of the STAT3 protein so as to regulate and control a downstream BCL2 / CASP3 apoptosis pathway, thereby playing a role in treating OSCC. Molecular docking results further show that rutin and STAT3 have strong binding capacity. The invention discloses a new application of rutin as an STAT3 inhibitor in treating oral squamous cell carcinoma, and provides a new strategy and a candidate compound for developing high-efficiency and low-toxicity OSCC treatment medicines.

The invention provides halogen-free soldering flux and halogen-free soldering paste, and belongs to the technical field of electronic packaging materials. The halogen-free scaling powder comprises a corrosion inhibitor, an active agent and a solvent, the corrosion inhibitor is composed of sodium lauroyl sarcosinate and rutin, and the mass ratio of the sodium lauroyl sarcosinate to the rutin is (1-4): (1-4); the active agent is composed of organic acid and organic acid salt; the solvent is composed of a glycol ether solvent, an alcohol solvent and a terpene alcohol solvent; based on the mass of the halogen-free scaling powder, the mass percentage of the corrosion inhibitor is 1-3%; the mass percentage content of the active agent is 5-8%; the mass percentage content of the solvent is 30-45%. When the halogen-free soldering flux is added into the halogen-free soldering paste, the storage stability, the printing performance and the welding performance of the halogen-free soldering paste can be improved.