Oil and grease contains human body can not synthesize linoleic acid, linolenic acid, and a variety of oil-soluble vitamins (ADEK), but also can be used as an industrial raw material, soap, paint, leather, medicine, lubrication and so on. Proposed fatty acids, fatty alcohols used in the production of candles, cosmetic base, emulsifiers, plasticizers, oil for feed, but also contains phospholipids (atherosclerosis, hyperlipidemia, hepatic dysfunction), sugars, vitamin E, sterols, soy isoflavones to improve the ability of menopausal women to fight heart disease, saponins to reduce plasma cholesterol and the prevention of rectal cancer
China's demand for 25 million tons of vegetable oils, domestic Supply accounted for only 9.4 million tons, held in 1972, the National Oil Leaching Conference, 1987 Beijing Nanyuan Oil Factory built China's own design and production of the first 50t / d full continuous oil refining production line.
Proteins with a diameter of 2um-20um protein body exists in the seed cells, oil and grease to 0.2um-0.5um sphere scattered in the gap between the protein body. Enzymes important to oil production in oilseeds, lipase (hydrolysis and synthesis of fat, 30-40 degrees), fat oxidase (catalyzes the generation of hydroperoxides from high-level unsaturated fatty acids and fatty acid esters, oxidative degradation products associated with soybean fishy smell), phospholipase (hydrolysis of phospholipids to produce glycerol, fatty acids, choline), urease (anti-nutritional factors in soybeans, humid-heat treatment to passivate and destroy), and other enzymes, sugar, oilseeds Seeds contain mainly oil pentose and hexose. Lipids, can be saponified (glycerides, glycerides, fatty acids, phospholipids, sugar esters, ether esters), unsaponifiable (neurophosphatidylinositol, waxes, sterols, pigments, hydrocarbons, antioxidants, trace metals), pigmentation is a fat concomitant
The world's total production of soybeans in the 350 million, China's production of about 19 million, the demand for more than 100 million tons. Oil storage, the purpose of the weight does not occur loss, quality does not deteriorate. Physical properties and physiological properties affect, among them physical properties are oilseed dispersal, automatic grading, porosity, adsorption and thermal conductivity. Soybean storage period, prone to hygroscopic (good air permeability of the seed coat, protein and other hydrophilic colloid content is high), mold (mostly occurring in the lower part of the heap or on the upper layer, the lower part due to hygroscopicity, the upper part due to condensation, generally not more than 30cm), soaked in oil ruddy (moisture exceeds 13, the temperature exceeds 25 easy to change ruddy, protein denaturation, destruction of the state of the **** storage), intolerance of high temperature (about 20, water-soluble nitrogen decreased by 5%, and Oleic acid rises 37%), loss of germination power (temperature above 25) and other phenomena, but good insect resistance (seed coat hard, containing more fiber and wax). Storage technology: removal of impurities, drying and de-watering, ventilation and heat dissipation (about 20 degrees, can be stored for more than 2 years, 25 degrees storage 18 months, 30 degrees 8-10 months)
Pressing process:
Sieve, vibrating sieve, plane rotary sieve, rotary sieve,
wind separator, specific gravity method of de-stoning, magnetic separation, dust collector
Softening, temperature and moisture regulation of oil, elasticity, 70 degrees. Moisture regulation, elasticity, 70-80 degrees 15-30 minutes, moisture 13-15%
Rolled billet, soybean thickness of 0.3mm,
Oil in the process of extrusion and expansion by the instantaneous (expansion time of 20-30S) high temperature cooking effect, 0.35-0.45mm, into the expansion machine moisture 10-11%, the temperature of 60-65, out of the expanding machine material grain Temperature 105-110 degrees, moisture content of 12-13%, after drying and cooling so that the moisture content of 8-10%, the temperature of 50 degrees, into the puffing machine saturated steam pressure of 0.65-0.75Mpa,
Leaching method of oil extraction using the principle of solid-liquid extraction, leaching method of extracting the oil after meal residual oil in less than 1%,
6 extraction solvent oil is commonly known as light gasoline in the leaching, petroleum fractional distillation from the A large number of hydrocarbon mixtures, boiling point range of 60-90 ℃, which requires a mixture of oil in the evaporation, steam and wet meal evaporation solvent to raise the temperature, which will cause the oil and meal quality indicators decline, this shortcoming prompted the production and application of China's production and distillation range of the narrower of the light gasoline and industrial hexane to do the extraction of solvents, but also easy to form explosive mixtures with the air, the steam impact on the human nervous system.
Industrial hexane, (96% -98%), boiling point 66-69 ° C, flash point -32 ° C, spontaneous combustion point of 240 ° C, hexane gas and air mixed with a concentration of 1.25% -4.9% will explode, the vapor is toxic to the human nervous system.
Hexane is included in one of the 169 chemicals that break the atmosphere, and 40% of the leaching plants in the United States use methyl pentane as the leaching solvent. Leaching solvent research mainly consider two aspects: one is the safety of edible oils and fats, and the other is the functionality of the extracted oils and fats. Currently there are three problems that need to be solved for solvent application, one is to solve the solubility problem of non-polar edible fats and oils in polar solvents. Secondly, the solvent is completely removed from the oil and meal extracted to ensure food hygiene and safety. Third, the production process is fully realized heat exchange technology, so that the production of energy consumption than the existing production process is greatly reduced.
The new leaching process to explore, one is a polar solvent leaching, ethanol leaching can be extracted from soybeans without refining the oils and fats, you can get a high protein and amino acid content of the meal,. Second, acetone leaching, hydrophilic and lipophilic properties. Third, mixed solvent leaching, fourth, liquefied gas leaching, the use of compressed liquefied gas mixture, as well as other hydrocarbon mixtures, such as No. 4 and No. 6 solvent leaching; fifth, supercritical fluid leaching, supercritical carbon dioxide leaching, the gas at the critical temperature and the critical pressure of the critical temperature and the critical pressure of the performance of having the nature of the liquid.
Mixed oil suspended 0.4%-1.0% of the solid meal, through filtration (self-filtration, intermittent filter 40 mesh 80 mesh 120 mesh screen, spin-liquid separation), sedimentation (gravity settling) first meal separation, and then according to the difference between the boiling point of the mixed oil evaporation (indirect steam heating, evaporation alone is not feasible to completely remove solvents in the mixed oil, because with the concentration of the boiling point of the mixed oil increased) (indirect steam heating, evaporation alone is not feasible to completely remove the solvent in the mixed oil, because as the boiling point increases with the concentration of mixed oil, it is easy to lead to oil and grease and the accompanying undesirable reactions, so to steam), steam (steam distillation, heated mixed oil into the water vapor to talk about solvent vapors away), and finally through the determination of the leaching of oil soluble residue to determine whether the residual capacity is up to standard, the requirements of the following 0.05%. Leaching oil good or bad in addition to the selection of solvents, depends largely on the steam process conditions, mixed oil processing stage of steam consumption accounted for a large proportion. Mixed oil evaporation and gas process under full negative pressure has been widely used and achieved remarkable results, negative pressure under the concentration of 26% mixed oil by the first evaporator 50 ℃ (heat source from the DT steam stripper 80 ℃ mixed steam) concentration increased to 70-75%, by the second evaporator concentration increased to 90-95%,
Mixed oil evaporation and vaporization process, due to the role of water and temperature, acid price Elevated (0.3-0.5) due to moisture and temperature, which is particularly noticeable at temperatures above 130°C and increased fouling of the evaporator and vaporizer tower heating surfaces. The evaporation and stripping processes also vaporize small amounts of free fatty acids, which can slightly reduce the acid price.
Evaporation and vaporization process of phospholipid oxidation decomposition, sugar coking, reducing sugar and phospholipid liquid role in the formation of black phospholipids to deepen the color of oil, it is recommended to use brine to wash the mixed oil, wash out the sugar substances. Colored substances in the evaporation vapor extraction process, due to the temperature higher than 100 ℃, carotenoids are destroyed.
Evaporation of the vapor extraction stage can be found in the first products of lipid oxidation such as peroxides, and then they undergo decomposition, and further formation of thermally stable second products, such as epoxides, oxygenated acids, carbonyl compounds, etc. In order to reduce the oxidation of the concentration of oxygen in the steam must be reduced.
The vaporized gross oil is cooled by a gross oil dryer.
Wet meal processing, generally containing 25% solvent, by the desolvation, drying, cooling treatment, one is to ensure that the desolvation to a minimum, the second is to passivate and destroy the meal in the harmful toxins and anti-nutritional components. DT Steam Dehulling Machine steam injection to take away 90% of the solvent,
baked meal time 15-25min, out of the meal moisture 14-15%, meal temperature of 100-105 ℃, the solvent steam dehulling machine discharges
The meal is dried and cooled to form a finished meal, different grades of soybean meal for different purposes, a (48) laying hens, sows, piglets, chicks; secondary (16-45) broiler, adult pigs, fish; tertiary (40-41) out of the pig, cattle; fourth (<38) cattle, sheep, rabbits and other ruminants
The meal is generally crushed using a hammer mill, crushing particle size control In 4-6 mesh.
Soybean urease (animal body urea decomposition into carbon dioxide and ammonia, red blood cells have agglutination), trypsin inhibitor (inhibit the activity of trypsin in the animal body, affecting the protein digestion and absorption), saponins (inhibit the growth of) blunted in the process of DT, destruction.
How to automatically detect the phenomenon of heat in the warehouse meal?
Oil refining process:
Gross oil suspended impurities are removed by gravity sedimentation, centrifugal separation and filtration
Moisture is removed by decompression drying
Gummy impurities: phospholipids and proteins, sugars, mucilage
Phospholipids are both rich in nutrients and antioxidant potentiation of fats and oils, which will make the fats and oils dark, high temperature scorching, emulsification in alkali refining, increase of adsorbent in decolorization, poisoning of catalyst in hydrogenation. Hydrated phospholipids contain polar groups, choline, ethanolamine, inositol, serine, etc. Non-hydrated phospholipids are glycerophosphoric acid, lysophosphoric acid, phosphatidic acid.
Lecithin added to the fresh soybean processing oil, can effectively remove non-hydrated phospholipids, on the damaged or longer storage life of raw materials processing oil non-hydrated phospholipids removal does not have much effect.
The protein and sugar content in the gross oil is not much, but because of its hydrophilicity, it is easy to promote the hydrolysis and rancidity of oil.
Fat-soluble impurities: free fatty acids (alkali neutralization method to remove), sterols (converted to vitamin D under the action of the ultraviolet, the formation of alkali refining of fats and oils in the soap foot adsorption of sterols, decoloration process to remove most of the sterols, high-temperature deodorization to remove some of the sterols), tocopherols (vitamin E is a mixture of tocopherols, the processing of the loss of not much), pigments (carotenoids are more common in oxidation, and easy to grab with the oil in the process of oxygen, oxidation to a certain extent to become oxygenated. Oxygen, oxidized to a certain extent to become a carrier of oxygen, promote the rancidity of fats and oils), hydrocarbons, waxes and fatty alcohols.
Hydration degumming - acid refining degumming - alkali refining deacidification - desaponification water washing - decolorization - deodorization
Decolorization, pigment is divided into 3 categories, one is organic pigment, the second is organic degradation products, such as proteins, sugars, phospholipids degradation products, and the third is the chromogenic, oxidation or specific reagents act to develop color. In alkali refining, acid refining, hydrogenation, deodorization and other sections have auxiliary decolorization, evaluation of the color there are two methods, one is the Rovibon colorimeter method for light-colored oils, deacidified oils, etc., and one is the spectrophotometer method, mainly used for dark-colored fats and oils in the wavelength of 400-700mm between the measurements. Used in the adsorbent: natural bleaching earth, the scientific name of bentonite, composed of montmorillonite; activated white earth, bentonite as raw material processed and processed, after decolorization of the residual earthy taste by deodorization; activated carbon, expensive, high oil absorption rate, generally used with activated white earth; zeolite, composed of silica, alumina, decolorization can reduce the acid value of fats and oils and water; Aubergine earth, a magnesium-rich fibrous mineral, the farmers use as feed. Composition is silicon dioxide, farmers as feed additives, and activated white earth than the dosage, oil loss, cheap, difficult to filter; diatomaceous earth, the main ingredient of silicon dioxide, decolorization coefficient is low, high oil absorption, generally do filter aids; silica gel, silicon dioxide, the cost is high, generally more filled into silica gel columns for filtering and decolorization.
Deodorization, high temperature and high vacuum conditions with the help of water vapor distillation to remove odor substances, the use of odor substances and triglyceride volatility differences, total loss of deodorization, including distillation loss (low molecular aldehydes, ketones, and free fatty acids) and splash loss (grease splash)
Note: Anisic amine value characterizes the number of aldehydes, ketones, quinones, and other secondary products inside the oil, the majority of the journals in the literature are Most of the literature in journals claim that anisidine value can be greatly reduced. However, the phenomenon observed in the actual production is not in accordance with the literature. The more the content of secondary products such as aldehydes, ketones and quinones, the easier it is to produce small molecules of aldehydes and ketones during the heating process. Comparison of anisidine values of four oil samples, finished oil, decolorized oil, dried oil and gross oil, showed that decolorized oil had the highest anisidine value and finished oil had a lower anisidine value than it. In the process of decolorization, there are many secondary products of peroxides of oils and fats, and the temperature is not enough to decompose the secondary products into smaller small molecules, so the anisidine value is high; while in the process of deodorization, the high temperature makes the secondary products decompose, so the anisidine value is slightly lower. Detection of anisidine value: test principle: in acetic acid solution, make the aldehydes and P-anisidine reaction in oil and grease, and then measure its absorbance at 350nm, so as to get the value of P-anisidine. Procedure: Weigh 2.0g of oil sample in a 25ml volumetric flask, dissolve with iso-octane and set the volume. Accurately weigh 5ml of oil sample in a 25ml colorimeter tube, accurately add 1ml of P-anisidine reagent with a pipette and shake, and then let it stand for 10min. firstly, use iso-octane solvent as a blank to determine the absorbance Ab of the oil sample, and then use 5ml of iso-octane+1ml of P-anisidine reagent (let it stand for 10min) as a blank to determine the absorbance AS of the oil sample solution. P-Anisidine Value ( PAV)=25*(1.2AS-Ab)/W Preparation of P-anisidine reagent: accurately weigh 0.25g of P-anisidine, first dissolve it in a beaker with glacial acetic acid, wash it, inject it into a 100ml volumetric flask, and fix the volume.