55 results about "Kjeldahl method" patented technology

The invention relates to a method for determining element content of substances, in particular to a method for conveniently and rapidly determining total nitrogen content in an organic material including the content of the organic nitrogen and the content of inorganic nitrogen. The method mainly adopts a concept for combining the digestion with sulfuric acid and titration of ammonia ion with formaldehyde, so that the three steps of alkalization distillation, absorption with boric acid and acid titration in a kjeldahl determination method can be omitted, and equipment, instruments and chemical reagent used in the method are ordinary, so that the determination of the total nitrogen content in the organic material becomes convenient and rapid, and remarkable economic benefit and social benefit can be realized.

The invention belongs to the field of peanut protein deep processing, and provides a formula of composite peanut protein powder. The formula is characterized by consisting of low-temperature cold-pressed semi-defatted peanut protein powder, mung bean flour, millet flour, peanut shell water-soluble dietary fiber and xylitol. The invention also provides a method for preparing the composite protein powder, which comprises the following steps of: weighing raw materials; mixing; soaking in aqueous solution; grinding into pulp by using a colloid grinder; preparing solution; homogenizing at high pressure; and performing freeze drying. The composite peanut protein powder prepared by the method has high protein content of over 40 percent through a Kjeldahl method, comprehensive and balanced nutrients, and can be drunk after being made by boiling water. Therefore, the composite peanut protein powder has the advantages of high protein content, easy solubility in boiling water, suitability for different groups, simple and easy operation of production process, suitability for industrial production and good economical and social benefits.

The invention relates to a method for producing organic environment-friendly horticultural humus, and discloses a method for producing organic ecotype insecticidal and environment-friendly horticultural humus. The method comprises the following steps of: adding 10kg of oleander chip into each 1,000g of camellia shell and stirring to prepare a material, determining the content of total carbon in the material by a potassium dichromate volumetric method, and determining the content of total nitrogen by a micro Kjeldahl method; calculating the content of pure nitrogen which is required to be added on the basis of the carbon nitrogen ratio of (25-30):1; and adding 1kg of fermentation strains and 3kg of pure nitrogen, stirring uniformly, regulating and controlling composting time to 20 to 60 days to fulfill the production aims of garden surface coverage and soilless culture substrates, and oven-drying or air-drying until the water content is less than 30 percent. The process is simple, the source of raw materials is stable, and the humus is cheap in price and meets environmental protection requirements. By the method, the problem of the pollution of the partial forestry waste is solved,and a recycling and added-value utilization way is also explored for forestry waste.

The invention relates to a method for detecting the basic protein content of milk, and provides a method for determining basic protein substances in the milk, in particular for the determination of milk basic proteins. The method comprises the following steps of: 1) removing caseins and fats in an acid regulation centrifugation way; 2) adsorbing the caseins by using cationic resin; 3) collecting eluent; and 4) determining the proteins by utilizing a micro Kjeldahl method. The invention also provides a method for collecting the milk basic proteins by utilizing chromatography equipment instead of manual collection.

The invention relates to a method for rapidly monitoring the solubility of protein in a preparation process of beer wheat malt. The method can be used for judging the wheat malt library value according to the measurement results of water-soluble protein content and FAN content in green wheat malt, and aims at rapidly and accurately judging the solubility of green wheat malt protein. A conventional wheat malt library value measurement method mainly refers to the standard of QB/T1686 beer wheat malt. A standard method comprises the steps of drying green wheat malt into finished wheat malt, carrying out EBC saccharification and then respectively measuring the content of soluble nitrogen and the total nitrogen of wheat malt in a kjeldahl method. The standard method is more in steps, complicated in operation, long in time consumption (about 30h) and high in cost. The method, which can judge the solubility of the wheat malt protein according to the water-soluble protein content and the FAN content in the green wheat malt, has the total time consumption of shorter than 3h, can rapidly and accurately judge the wheat malt library value, reasonably control the germinating time and accurately judge the finished wheat malt library value, and is capable of saving the analysis time and improving the processing efficiency and quality of wheat malt.

The invention provides a method for extracting protein from grain finemeal, which comprises the steps: firstly saccharification is carried out to the grain finemeal, and then the protein residue after saccharification is separated and purified by the alkaline extraction and acid precipitation method for obtaining high-purity protein. The saccharification process solves the technical problems that some grain protein is combined with starch tightly and is not easy for being separated, and the extraction of protein is difficult; the alkaline extraction and acid precipitation process effectively improves the extraction rate and purity of grain protein; and the saccharification liquid can be used for other usages, thereby saving the resources to the largest extent. The protein extracted by the invention can be analyzed and determined with kjeldahl method-GB/T 5009.5 and is not less than 80 percent when being counted by crude protein content (NX6.25 dry basis), and the yield thereof is 6-10 percent.

The invention belongs to the technical field of Kjeldahl nitrogen measurement methods, and in particular relates to a novel method for measuring Kjeldahl nitrogen. The novel method for measuring Kjeldahl nitrogen achieves the purposes of measuring nitrogen content in a measured object by the following steps of: digesting the measured object according to a conventional Kjeldahl method to obtain a digestion solution, adding water to dilute the digestion solution and adding alkaline to obtain an alkaline digestion solution, heating and blowing off the digestion solution with gas, absorbing the blown-off gas with an absorption solution, and measuring the difference value between the electrical conductivities before and after the absorption by a conductivity meter.

The invention discloses a rapid protein detection kit as well as a detection method and an application using the same. The detection kit comprises a biuret reagent, a surfactant and a cosurfactant. According to the detection method disclosed by the invention, through addition of the surfactant and the cosurfactant in the biuret reagent, the prepared microemulsion has the characteristics of solubilization and sensibilization, the improved biuret method has the advantages of high sensitivity, simplicity in operation, less interferents and good repeatability. The detection sensitivity of the detection method disclosed by the invention on protein is 6-11 times that of the traditional method. The detection method can be applied to detection of a trace protein sample, and the relative error of the detection method is between 0.28% and 0.60% as compared with that of an national standard kjeldahl determination method. The detection method disclosed by the invention has good precision and accuracy.

The invention discloses a method for determining the content of organic amine. The method comprises the following steps: step 1: determining content w2 of inorganic amine in a sample to be detected by adopting a distillation titration method; step 2: determining content w1 of total amine in the sample to be detected by adopting a Kjeldahl method; and step 3: calculating the content of the organic amine in the sample to be detected, wherein content w3 of the organic amine in the sample to be detected is equal to (w1-w2), and sequences of the step 1 and the step 2 can be exchanged or the step 1 and the step 2 can be carried out simultaneously. Compared with a traditional gas chromatography for determining the content of the organic amine, the method for determining the content of the organic amine has the advantages of relatively low cost and relatively simple operation. Meanwhile, the method also has the advantages of relatively high precision, accurate determination result, good repeatability, environment friendliness and the like, and can be applied to conventional analysis and quality control of the content of the organic amine.

The invention provides a method for influencing moisture soil nitrogen mineralization characteristics and crop yield by long-term positioned fertilization. By means of in-situ field and anion-cation exchange resin process, the influence of long-term application of nitrogen fertilizer and supportive phosphorus potassium fertilizer upon non-calcareous moisture soil nitrogen in-situ field mineralization characteristics, crop nitrogen absorption and crop yield is studied, and a relation of the influence with crop nitrogen absorption and crop yield is studied; total nitrogen of soil and plants is measured by Kjeldahl determination, NO3<->-N and NH4<+>-N in soil and ion exchange resin bags are extracted with KCl solution, and after filtering, determinations are made respectively by means of dual-wavelength ultraviolet spectrometry and Nessler's reagent colorimetry. Theoretical basis is provided for the sustainable development of a soil nitrogen nutrition bank, controlling of soil nitrogen supply in this area and achievement of high crop yield.

The invention discloses a method for detecting protein content in regenerated protein fiber. The method includes weighing a certain amount of regenerated protein fiber baked to constant weight, into adigestive tube, adding a certain amount of copper sulfate, potassium sulfate and concentrated sulfuric acid, then digesting the mixture in a constant temperature digestion furnace for a period, and then performing test on a Kjeldahl analyzer after cooling. The protein content can be obtained by performing converting according to the set protein conversion coefficient. The method overcomes the shortcomings of complicated operation and long test period of the existing Kjeldahl method and the sodium hypochlorite method, and has the advantages of short test period, wide application range, high efficiency, simple operation and good repeatability.

The invention relates to a method for preparing thallus protein extractum from bacterial residue of amino acid fermentation liquor. The method comprises the following steps of: filtering amino acid fermentation liquor with a ceramic membrane, taking a concentrated slurry fungus residue solution, and measuring the protein content by a Kjeldahl determination method; adjusting the pH value of the concentrated slurry fungus residue solution to 7.0-8.5 by using alkali, carrying out high-temperature high-pressure treatment, and adding protease for enzymolysis; after the enzymolysis reaction is finished, preserving heat, adding activated carbon, and performing decolorizing and filtering to obtain a decolorized liquid; and preparing the extractum: concentrating the decolorized liquid under reducedpressure to obtain the thallus protein extractum. The method subjects amino acid fermentation thalli to high-temperature high-pressure wall breaking, enzymolysis, filtration and concentration so as to obtain the extractum with a micromolecule bioactive peptide (namely, oligopeptide) content exceeding 90%, thereby greatly improving the added value, wherein the market price of the thallus crude protein is about 2500 thousand yuan per ton, and the market price of the extractum is about 20-30 thousand yuan per ton.

The invention relates to a method for quantitatively detecting the content of protein in protein viscose. The method comprises the following steps: (1) arranging a test sample in a measuring bottle, and transferring the dried test sample to a constant weight into a conical flask with a stopper; (2) diluting a well-calibrated sodium hypochlorite stock solution to given concentration, arranging the diluted sodium hypochlorite stock solution into the conical flask with the stopper, covering a bottle cover, oscillating the moistened test sample, and arranging the test sample into a constant-temperature oscillation water-bath pot and oscillating at a given temperature; transferring residues into a glass sand core crucible with known drying mass, and washing the residues by utilizing the sodium hypochlorite sodium solution, tertiary water and dilute acetic acid respectively; (3) calculating the content of the protein according to the reduced mass of the protein viscose test sample before and after being processed by sodium hypochlorite. By adopting the method, the weaknesses that the test period is long, the danger in operation is high, toxic and harmful gas is likely to generate, and the like in the classical kjeldah method for measuring the content of the protein can be overcome. The method has the advantages of good test reproducibility, simplicity in operation, accuracy conforming to the analysis requirement, slight environmental pollution and the like.

The invention discloses colored nutritive formula organic rice. The colored nutritive formula organic rice contains the following raw materials in percentage by weight of the organic rice: 50% of organic brown rice, 10% of organic black rice, 10% of organic red rice, 10% of organic green rice, 10% of organic purple rice and 10% of organic yellow rice. The invention further discloses a making method of the colored nutritive formula organic rice. The making method comprises the following steps of taking materials, performing preliminary cleaning, removing stones, performing husking, performing rice milling, performing classification, performing polishing, compounding colored organic rice, separately measuring the water content, the amylose content, the crude protein content and the crude fatcontent of raw material rice by a 105 DEG C constant mass method, an iodine combination colorimetric method, a kjeldahl method and a Soxhlet extractor method, selecting the materials including the organic brown rice, the organic red rice, the organic yellow rice, the organic green rice, the organic purple rice and the organic black rice, of which the water mass content is 13-16%, the amylose masscontent is 18-22%, the crude protein mass content is smaller than or equal to 10% and the crude fat mass content is smaller than or equal to 0.45%, compounding mixed colored organic rice, and performing mixing in a quantitative manner, so that the organic rice can integrate various nutrients.

The invention discloses a method for extracting livetin and oil from larimichthys crocea eggs at the same time. The method comprises the steps of larimichthys crocea egg freeze-dried powder preparation, freeze-dried powder dissolution, primary extraction, precipitation dissolution, secondary extraction, mixing and dialysis. According to the method for extracting the livetin and the oil from the larimichthys crocea eggs at the same time, a sodium chloride solution is adopted for digestion at a room temperature, and through centrifugation, the livetin and the oil are separated according to different tensity so that the oil and protein can be recovered at the same time; the livetin recovery rate is up to 76-82%, a kjeldah method is used for detecting the protein purity which is up to 80% or above, and through mass spectrum identification, the livetin content accounts for more than 99% of the total protein content; the oil recovery rate reaches 22-23%, and the oil purity is reaches 90% orabove; the emulsibility of the larimichthys crocea egg livetin prepared through the method is significantly improved compared with that of the freeze-dried powder and is significantly better than thatof soy isolate protein, so that the method has important significance in larimichthys crocea egg deep-processing.

The invention discloses a method for determining the nitrogen contents of different organs of a plant. The method comprises the following steps of taking a plant sample, separating according to organs, drying the sample, grinding and sieving, acquiring a reflectivity spectrum of the powder sample by using a hyperspectral camera, meanwhile, determining the nitrogen content in the sample by adoptinga Kjeldahl determination method, and establishing a spectral prediction model of the nitrogen content. According to the method, different organs of the wheat plant are subjected to nitrogen content determination, and an organ-specific nitrogen content prediction model is established, so that research on nitrogen transfer among the organs can be carried out in a targeted manner. According to the method, the spectral camera is used for acquiring reflectivity spectral data, so that the requirement on the sample amount is low, multiple groups of samples can be simultaneously collected, and the detection flux is improved. According to the method, prediction model construction is carried out by adopting an unprocessed original spectrum, and model construction is carried out by adopting an opensource algorithm, so that the spectrum analysis threshold is simplified, and the spectrum technology can be better applied to the technical field of agriculture.

The invention relates to the field of measurement of pasture quality, and in particular relates to a method for measuring crude protein content in Phalaris arundinacea by using near infrared spectrum.The method comprises the following steps of 1, widely collecting representative Phalaris arundinacea samples; 2, collecting near infrared spectrum data of modeled samples; 3, measuring the crude protein content in the samples by using a kjeldahl determination method; 4, building a calibration model; 5 verifying the calibration model; and 6, measuring the Phalaris arundinacea samples to be measured. The measurement method is easy to acquire samples and convenient to measure; continuous and unlimited analysis can be performed after the model is built, the time for being on the machine only needs 16s, the test period is shortened, the analysis efficiency is greatly improved, the measurement result is good in reproducibility and high in stability, meanwhile no chemical reagent is used, no pollution and damage are generated. The method can be used for quickly measuring the plenty of material, and has the wide application prospect in the aspects of Phalaris arundinacea quality assessment, quality breeding, daily ration configuration and forage product circulation.

The invention discloses a method for simply and conveniently measuring the content of a non-protein nitrogenous substance in a milk product. According to the method, casein serves as a standard substance; a kjeldahl method and a colorimetric method are used for measuring simultaneously; a correction coefficient is calculated; a calculated result of the colorimetric method can be converted into total nitrogen of the kjeldahl method. When a sample is measured, the two methods are used for measuring simultaneously, and the result of the colorimetric method is converted into a result of the kjeldahl method, and deducted from total nitrogen of the kjeldahl method, so that the content of the non-protein nitrogenous substance in the milk product can be obtained. A colored sample is decolorized and then measured by the method, and milk powder can be diluted and then measured by the method.

The invention belongs to the fields of genetic breeding and innovation of germplasm resources, and provides an economical novel method for quickly screening high-protein variety of paddy rice. The method comprises the following steps of: comparing by taking the paddy rice variety which is tested by a Kjeldahl method to have the protein content of about 8-9% as medium-protein content, randomly selecting one grain of polished rice from each variety to be tested, dipping in distilled water in a 1.5ml small centrifuge tube for 3 hours, breaking the polished rice to be naturally fractured by hands, dyeing by acridine orange (0.02%, v/v) for 10 minutes under the condition of keeping out of the sun, and washing by the distilled water for 1 minute. The Nikon ECLIPSE 90i laser scanning confocal microscope is used for observing, excitation light is 488nm, emitted light is 575nm-605nm, and NIH Image 1.6.2 software is used for analyzing an image. The transverse facial cleft of the polished rice is higher in protein content compared with the coarse surface, the higher the roughness is, the higher the protein content is, and otherwise the protein content is lower. The method can be used for quickly screening the high-protein variety of the paddy rice by few samples for the subsequent genetic breeding, so that the quality of the paddy rice can be improved.

The invention provides an analytical method for measuring the content of mildronate intermediate 3-(2,2,2-trimethylhydrazine) methyl propionate methylsulfate by use of nonaqueous titration, and relates to an analytical method for measuring the content of a mildronate crude drug intermediate. The analytical method is characterized in that kjeldahl determination is adopted and nitrogen in a C7H17N2O2SO4-CH3 monomer is measured by use of a neutral titration method after digestion, and therefore, the purpose of measuring the main content of the intermediate can be achieved. The analytical method comprises the following specific measurement steps: putting a test sample into a Kjeldahl flask, adding water for dissolving, adding a sodium hydroxide test solution, heating for distillation, guiding the distillate into a boric acid solution, taking methyl red-bromocresol green as an indicating liquid, titrating by use of an inorganic acid titrant until the terminal point that the solution turns to grey purple from blue-green, and then calculating the content of C7H17N2O2SO4-CH3 according to the dosage of the titrant. The detection result obtained by the method is capable of achieving basically consistent effects with an HPLC (High Performance Liquid Chromatography) detection result. The method is simple and quick, precise in measurement result and high in accuracy, and can be applied to conventional analysis and quality control of the mildronate crude drug intermediate 3-(2,2,2-trimethylhydrazine) methyl propionate methylsulfate.

The invention discloses a method of judging fertilizing amount by utilizing citrus leaf nutrients. The method comprises the following steps: 1, setting a plurality of sample plots in a citrus garden plot to be tested; 2, selecting leaves on the top of spring vegetative shoots of a current year and mixing the leaves into a leaf sample; 3, removing dirt and petioles, carrying out enzyme deactivationunder the condition of 100 DEG C, and placing in a constant temperature oven with the temperature of 75 DEG C for baking for 24 hours; 4, crushing and sieving the sample, adding concentrated sulfuricacid and hydrogen peroxide, and carrying out boiling elimination at 300 DEG C; 5, measuring N by adopting kjeldahl determination, measuring P by adopting a molybdenum-antimony anti-colorimetric method, and measuring K by adopting an atomic absorption method; if N is 2.40-2.70%, P is 0.12-0.16%, K is 1.00-1.40%, P/N is 0.050-0.059, and K/N is 0.416-0.519, a citrus tree is balanced in nutrition. The method of judging fertilizing amount by utilizing the citrus leaf nutrients can judge deficiency of nutritive elements and balance conditions of the various nutrients, and reduce adverse effects ofblind fertilization on soil.