Due to the different chemical composition and physical characteristics of various grain and oil commodities, their storage methods and management measures are also different. According to the characteristics of different grain and oil, taking into account the local actual conditions, keeping all kinds of grain and oil is the basic task of grain and oil storage. It has very important practical significance.
(I) Rice and Rice Rice is one of China's major food crops and has a long history of cultivation. In our country since the Northern Song Dynasty, its output has been at the top of the grain. Rice production in Asia accounts for about 95% of the world's total rice production, China accounts for 35%, and rice production ranks first in the world. The main producing areas of rice in China are distributed in the Yangtze River and Pearl River basins. According to statistics, rice production in Sichuan, Hunan, Hubei, Guangdong, Jiangsu, Zhejiang, Anhui and Jiangxi accounts for more than 70% of the country's total rice production.
1. Storage characteristics of rice (1) Rice kernels have a complete rice husk protection, and have a certain resistance to the damage of insects and mildew and the influence on the humidity and heat. Therefore, rice has better storage stability than normal finished food.
(2) Rice has a short ripening period and is prone to sprouting. Generally, there is no obvious ripening period of japonica rice, and the ripening period of japonica rice is only about 4 weeks. The water needed for germination of rice is the least compared with other foods. When the water content of rice is more than 25%, germination can take place as long as the temperature is appropriate. Therefore, whether paddy is stored in the field, in the drying area or after storage, the paddy can germinate as long as it is exposed to rain, condensation on the grain surface, and moisture, and its water content reaches 25% or more. Wherever rice with sprouts is produced, even if it is dried, its storage stability, nutritional quality and food quality will be reduced.
(3) Rice is easy to age. After high temperature in summer, rice is often aged, and the fatty acid value is increased, and the germination rate is decreased. Among them, japonica rice is more stable than indica rice, and japonica rice is the worst. The new rice harvested within one year has a strong respiration effect. Later, it is similar to the decrease in enzyme activity, and the dehydration of rice colloids degrades the water absorption and decreases the hardness of the rice. Therefore, the storage stability is enhanced and it is advantageous for long-term storage. However, in the long-term storage, every time a high temperature season occurs, its seed quality and food quality decline year by year. Therefore, rice storage should pay attention to storage and storage.
(4) The resistance to high temperature is weak. The colloidal structure of rice is loose and every time it passes through high temperature or heat, it will cause deterioration of quality. When the paddy was harvested without timely threshing and drying, the temperature was raised to 60°C and the grains began to turn yellow. Grains are yellow, also known as yellow rice, yellow rice. If the temperature rises to 70°C, the grains will all turn yellow. During the storage of rice, the greater the number of fevers, the faster the rate of yellowing increases. With the extension of the storage period, although it is not heated and mildew, it will increase yellowing. After 2 years of storage, the rate of yellowing is 5% or less, storage is 3 to 7 years, and yellow grains account for 5% to 10%.
(5) Pests that harm rice include corn elephants, rice elephants, valley fools, wheat moths, tyrants of grain, and sawtooth. After the spring season every year, the pests begin to breed in about April to May. The peak season occurs in the annual high temperature season.
(6) The vast majority of microorganisms attached to rice are mesophilic, mesozoic and aerobic microorganisms. High-moisture rice fever is caused by actinomycetes, bacteria, yeasts, and molds such as Rhizopus and Mucor. Low-moisture rice mildew is caused by the activity of dry fungi such as Aspergillus niger. of.
2. Storage method of paddy (1) Strictly control the quality of paddy in the newly imported rice, the impurity does not exceed 0.5%, and the moisture does not exceed 13.5%. The safe moisture of japonica rice in storage can be relaxed by 0.5% to 1% compared with japonica rice. The control of grain moisture content within safe moisture is the primary measure to ensure the safety of stored grain. Therefore, whether it is for grain banks or for farmers, it is very important to strictly control grain quality.
(2) Strengthen the resistance of Tongfeng cooling paddy to high temperature, the grain temperature is high, the speed of quality deterioration is fast, especially when the summer grain is put into storage, it is during the high temperature season. It is necessary to use mechanical ventilation to disperse the wet and heat in the valley heap in time. After the autumn rice is put into storage, it is necessary to seize the opportunity to make full use of the cold weather in winter and reduce the grain temperature. While cooling, it is necessary to prevent condensation on the grain surface.
(3) Closed storage at a proper time For generally low-moisture rice, the moisture-proof work must be completed before the spring season. Confined storage can delay the rise of grain temperature, which is conducive to safe summer.
(4) After storage of summer grain, natural anaerobic storage, double-low storage or slow-release fumigation technology can be adopted. That is, in the sealed grain heap, the dosage of 2-3 grams of aluminum phosphide per cubic meter and 0.07 mm of polyethylene can be used. The film is made into a pouch to wrap the drug and is then buried in the upper layer of the grain heap until the phosphine is slowly released to prevent pests and inhibit the occurrence of microorganisms.
(5) The storage and disinfection of warehouses and equipment should be well done when rice is in storage. Attention should be paid to the prevention of pest infections during storage and after storage. Once pests are found, measures must be taken to eliminate them.
3. The storage characteristics of rice The rice was shelled to obtain brown rice, and the brown rice was then ground to peel and embryo to become rice. Since rice is not protected by the chaff, the endosperm is directly exposed to space and is susceptible to external factors. Therefore, rice has poor storage stability and is far more difficult to store than rice.
(1) Rice is easy to absorb moisture and return moisture, causing rice to hydrophile. Hydrophilic colloids (starch, protein) are directly in contact with air and easily absorb moisture. Under the same conditions of temperature and humidity, balanced rice moisture is higher than rice. At the same time, wolfberry powder in rice not only has strong moisture absorption but also a large number of microorganisms, which easily causes fever, mildew, deterioration, and taste deterioration.
(2) Rice is easy to explode Irregular cracks in rice are called waist bursts. The reason why rice is popped is that because of the rapid drying of rice grains, the outer layer of rice grains dries faster, the water inside the rice grains shifts outward slowly, the drying rates of the inner and outer layers are different, the volume shrinkage is different, the outer layer shrinks, and the inner layer shrinks. The shrinkage is small and it causes a crash. In addition, rice grains can also cause a crash in the case of rapid absorption of moisture. When the rice is bursting, the broken rice becomes thick and sticky, which affects the quality of the food.
(3) Easy aging As the storage time is extended, the rice is gradually aged. When it is aged to a certain degree, Chen Mi smells, and at the same time, it changes taste. In addition to losing the original flavor of rice, it also shows that the gloss of rice is darkened, the viscosity of rice is reduced, and the hardness is increased.
(4) Easy to gray rice During the storage period, if the outside environment is high in humidity or the original water of the rice is high, ashing will occur. That is, the rice grain loses its original luster, and the surface of the grain of rice exhibits grayish-powdered crumbs and Baidao grooves, which is a precursor to the deterioration of the rice.
(5) Pest-prone pests The major pests that injure rice include rice figurines, corn elephants, tyranolium, rice flatworms, and long-horned flat gorillas.
4. The method of storage of rice (1) Conventional storage mainly uses the method of drying, natural low temperature, and confinement, and the rice of the processed machine is cooled to the temperature of the storage before being stored in the stack. High-moisture rice can be stored in short-term storage after ventilation, or it can be stored in cool and dry condition after ventilation.
(2) Low-temperature storage Low-temperature storage is an effective way to preserve rice. Using low natural temperatures, the low-water rice is processed in winter. After cooling, the rice is stored in a cool store. Using appropriate moisture-proof and heat-insulating measures, rice is kept at a low temperature for a long period of time. When the food temperature is relatively prolonged, rice is safe. An effective method. Using mechanical refrigeration to keep rice cool during the summer can also make rice safe. However, due to the large investment in refrigeration equipment and plant construction, it has not been fully promoted.
(3) Atmosphere storage For packaged or bulk rice, sealed with plastic film, use the respiration of rice and microorganisms in the grain heap, reduce oxygen naturally, or store carbon dioxide or nitrogen, which has good insecticidal and antibacterial effects. It can also be stored in hibernation in small packages, with 3 to 5 kilograms of rice per bag. It can be stored fresh in CO2 and can be safely stored for more than 1 year.
(4) chemical storage in sealed rice piles, according to the dose of aluminum phosphide 2 ~ 3 g / cubic meter, using 0.07 mm polyethylene film made of small bags into 15 ~ 20 grams of aluminum phosphide tablets, hung in Sealed bags are piled or embedded in the upper layer of the packaged grain to allow the slow release of phosphine, which can kill insects, inhibit bacteria and prevent rice from mildew.
(b) Wheat and flour Wheat is a staple food worldwide. China's wheat production is second only to rice. The main producing areas are south of the Great Wall and the Huanghuai Plains north of the Yangtze River, including Henan, Shandong, Hebei, southern Shanxi, Guanzhong in Shaanxi, and northern Jiangsu and Anhui.
1. Characteristics of storage of wheat (1) Long maturation period The ripening period of wheat is relatively obvious. It takes a few weeks or even 2 to 3 months for newly harvested wheat to complete the ripening period. The ripening effect of wheat is mainly manifested in its strong breathing ability. After the new wheat is put into the warehouse, due to the strong physiological metabolism, it is easy to cause sweating and warming of the grain piles. If no inspections are found and measures are taken in time, it will cause the grain surface to be moldy and rotten.
(2) Heat-resistance Wheat has high heat-resistance, and its protein and respiratory enzymes have high heat resistance. After a certain high temperature of wheat, it will not only lose its vitality, but also improve its quality. The use of the characteristics of wheat heat resistance, hot sealed storage, can kill insects, mold.
(3) Strong hygroscopicity The seed coat of wheat is thin, contains a large amount of hydrophilic substances, and easily absorbs the moisture in the air. In the same relative humidity, the balanced moisture of wheat is always higher than that of rice. The hygroscopicity of wheat is different because of different varieties. The cortex of red wheat is thicker and the moisture absorption is slower. White wheat has thinner cortex and stronger hygroscopicity; soft wheat has stronger moisture absorption ability than hard wheat.
(4) Weak Breathing Power Wheat's respiration after the ripening period is weak, and it is lower than that of other cereals. Red wheat has lower respiratory intensity than white wheat. Therefore, wheat has better storability and can maintain good quality for 2 to 5 years under normal conditions.
(5) Vulnerable to pests Because wheat has no shell protection, the cortex is thin, and the new wheat is in high temperature season for storage, which is suitable for breeding pests. The pests that harm wheat are mainly corn elephants, wheat moths, Indian rice bran, and Otani thief.
2. Method of storage of wheat (1) Thermally sealed storage method Heat-sealed storage of wheat can prevent pests and molds, promote the postharvest action of wheat, and increase the germination rate. The specific method is: use summer high-temperature exposure of wheat, pay attention to grasp the principle of late harvest, thin and diligent, in the barley temperature above 42 °C, preferably 50 ~ 52 °C, maintain 2 hours, and then quickly put the stacking, After the grain surface is leveled, the surface of the grain is covered with hot mats, straw curtains, etc., and the doors and windows are insulated. To do a good job of heat-sealing and storage, the first requirement is that the moisture content of wheat should be reduced to 10% to 12%. Secondly, sufficient temperature and closed time are required. After entering the warehouse, the grain temperature should be about 46°C and closed for 7 to 10 days. When the temperature is around 40°C, it must be sealed for 2 to 3 weeks.
(2) Low-temperature storage method Low-temperature storage is the basic approach for safe storage of wheat. Although wheat has high temperature resistance, it will continue to be stored at high temperatures and will reduce its quality. The low temperature storage can maintain the quality and germination rate. According to reports, wheat has been stored for 16 years under low-temperature, low-oxygen conditions and its quality has changed little, and it can be made into good bread. Using low temperature in winter, natural ventilation, mechanical ventilation and cooling, and then chilling and confining, will eliminate overwintering pests and delay the impact of high temperature on the outside, with good results. In addition, the use of underground storage of wheat can also delay the deterioration of wheat quality.
(3) Natural Hypoxia Storage The most widely used method at home and abroad is natural hypoxia storage. For the newly-introduced wheat, due to the effect of post-harvest, the physiological activity of wheat is strong and the respiratory intensity is high, which is extremely beneficial to the natural oxygen reduction of the grain heap. Practice has proved that as long as the closed work is done well, after 20 to 30 days of natural anoxic wheat, the oxygen concentration can be reduced to 1.8% to 3.5%, which can achieve pest control. The purpose of anti-mildew. If it is Chenmai every other year, the subsequent ripening effect has already been completed, and it enters a deep dormant state, the respiratory intensity is very weak, and it is not appropriate to carry out natural hypoxia. At this time, microbiological assisted oxygen reduction or charging of carbon dioxide and nitrogen into the wheat heap can be adopted. Meet the requirements of the atmosphere.
3. Flour storage characteristics (1) Hygroscopicity, poor storage stability Flour moisture higher than wheat, flour processing in summer than winter processing of high moisture, the actual moisture when stored in 13% to 14%, because the flour is a particulate structure, It has a large area of ​​activation and a faster rate of moisture absorption than wheat, so the flour tends to return to moisture in high humidity conditions. Flour is hot and mildew, mainly due to the high moisture content of the flour, or the respiration of the flour particles and the respiration of the microorganisms caused by the moisture absorption of the flour.
(2) The Yicheng Unity Block flour stack is stored for a period of time, and the lower layer is pressed into a mass due to the influence of the middle and upper layer pressure. The pressed flour is agglomerated and adhered with sterile silk. After being loosened and rubbed loosely, it can return to normal after leaving the warehouse and has no major impact on quality. However, if agglomeration occurs due to heat and mildew, it is not easy to restore looseness and quality is significantly reduced.
(3) The familiar and white flour of flour is stored for about 10 to 30 days after being stored in the warehouse. The quality is improved, the gluten strength is enhanced, the fermentation is good, the bread is made large and loose, the noodle is even and uniform, and the taste is soft. The delicious, gluten-improved effect is known as the maturation of flour. In addition, the flour is stored for a certain period of time, and the color of the flour gradually fades to white due to a slight yellowish color at the time of the first discharge, which is due to oxidation of the fat-soluble pigment in the flour. The nutritional properties of flour have not improved, but have also been reduced.
(4) The change of flour sour and bitter fatty acids is the main indicator of deterioration of flour quality. Even with the normal moisture content of flour, because of the hydrolysis of fat, the fatty acid increases regularly and the acid value increases; the flour with higher moisture content, due to the adverse effects of microorganisms, causes the accumulation of water-soluble organic acids, and the decomposition of fat causes the acid price. Increase faster. Wheat that has sprouted or overheated is made into flour and its rancidity is faster than normal flour.
4. Flour storage method The main technical measures for flour storage are to do a good job of confining moisture, stacking and preventing pests. The safe storage of flour is controlled within 13%.
(1) Closed moisture-proof flour is easy to absorb moisture, so moisture protection is very important. After the flour is put into storage, the plastic film should be sealed on the six sides. This will not only prevent moisture absorption, but also prevent insects and mildew infections. It can also keep fresh and dust-proof. For flour that needs to spend the rainy season, it is necessary to close the moisture barrier as soon as possible.
(2) Reasonable stacking For freshly processed flour, piles can be piled up first and then changed into large piles after cooling and loosening. In the dumping operation, only the upper and lower positions can be changed, and the original flour in the outer layer should still be placed in the outer layer so as to avoid putting the flour with large moisture content into the core, causing heat and mildew. In addition, due to the impatience of flour storage, it is necessary to combine the sales situation and promptly change positions.
(3) Strictly Preventing Pests Pests Fighting flour pests include tyrants, horned crows, and maggots. Pests often occur at the mouth of bags. Before entering the warehouse, the flour must be cleaned and disinfected as well as disinfected and disinfected. After storage, strict management is required. Once pests are found, they are treated with fumigation in a timely manner and sieved mechanically or manually to screen worms for sale. In addition, aluminum phosphide can be used for preventive fumigation according to actual conditions.
(three) corn and corn flour
1. The storage characteristics of corn (1) Large corn embryos, strong breathing, corn embryos, accounting for almost 1/3 of the total grain size, accounting for about 10% to 12% of the total grain weight. Since the embryos absorb moisture easily and contain a large amount of unsaturated fatty acids, they are prone to mildew when the storage environment is high in temperature and humidity. The fatty acid value of the corn embryo is always higher than that of the endosperm, and the rancidity begins with the embryo.
(2) The original corn has large moisture and uneven maturity. China's corn production areas are in the north, and when the corn harvests every year, the weather is cold, so the newly harvested corn moisture is 20% to 35%. Due to the same spikes, different pollination time at the top and base, leading to uneven corn kernel maturity, and corn being vulnerable to damage during threshing, so that the presence of immature and broken kernels increases the difficulty of corn storage.
(3) Easy-to-yield corn Due to the large size of the embryo, the fat content is high and the amount of bacteria is large. When the temperature and moisture conditions are appropriate, mildew easily occurs.
(4) Pests that are more likely to infect pests are more harmful to corn, including corn elephants, Dagu Pirates, Hexagrams, Pirates of the Valley, Indian pimple, whiteflies and wheat moths. Insect pests generally harm the embryos first. If Wangmi is infected with pests, it is much more serious than other grain types.
2. The storage method of corn In our country, the storage of corn in the north is mainly based on mildew, and in the south is mainly pest control. There are two kinds of storage methods for corn: grain storage and panicle storage. The national corn storage is grain storage, and most of the farmers use the pan-Tibetan method.
(1) Head and ear panicles The ear panicle is a typical ventilated ear reservoir. In North China and Northeast China, the high-moisture maize ear reservoir has great advantages due to the low temperature when harvesting corn. After a winter of natural ventilation, the moisture of corn in the coming April to May can be reduced to 12% to 14%.
(2) The first step in grain storage is to control the moisture in corn storage, requiring the moisture content of stored corn to be less than 13%. In addition, it can be used for hypoxia storage according to the characteristics of large corn embryos and strong breathing. Need to use double low storage, three low storage methods or the use of slow release fumigation method and other comprehensive methods of storage, to prevent corn heap fever, mildew, insects.
3. The storage characteristics and methods of corn flour are often washed with water during processing to increase the moisture content. Newly-opened corn meal has a higher temperature, generally 30 to 35°C. The high temperature and large moisture create conditions for the growth and reproduction of microorganisms. Maize meal has high fat content and is susceptible to oxidative deterioration. Therefore, corn flour is not easy to store finished grain, easy to mold, rancid bitter, not long-term storage.
During the storage of corn flour, the moisture content must not exceed 14%. In addition, corn flour should not use a large number of scattered methods, generally with bags, code into a ventilation rake, and 5 to 7 days dumping 1 times, the principle of dumping the same with the dumping of flour. If there is agglomeration, it should be kneaded in time. When conditions permit, it is best to use low temperature storage or modified atmosphere storage.
When processing corn flour, it is best to go to the embryo and then milling, so that it can extract corn embryo oil, increase economic efficiency, but also improve the silty, is conducive to storage.
(D) Other coarse grains
1. Barley's storage characteristics and methods Barley's acreage and yield ranks fourth in all grain species in China. Barley is processed and ground to make barley flour, which can be made into scones, made of barley paste, or blended with wheat flour to make other foods. In addition to food, barley is the main raw material for beer, alcohol, maltose and other products.
The physical, chemical and storage characteristics of barley are similar to that of wheat, and the storage methods are basically the same. Only the barley used in industry is used for germination. Therefore, the barley for industrial use should pay special attention to maintain its germination power. Barley can also be stored in a heat-tight manner, but the high-temperature sealing time cannot exceed 1 month, otherwise it will affect its germination power and reduce economic value.
2. The storage characteristics and methods of sorghum sorghum in our country's output ranks fifth in all grain species, is one of the staple food in northern China. Sorghum is not only edible, but also an important raw material for wine making, sugar making, making soy sauce, and vinegar.
The skin of sorghum is horny, the seed coat contains tannin, and it has a mildew-proof effect, which is favorable for storage. However, sorghum is often more miscellaneous, and is harvested in late autumn in northern producing areas. The temperature is low, and it is not easy to dry. The sorghum moisture of new storage is generally 16% to 25%, and it is still prone to mildew, causing the grain to turn dark brown or Black, with a strong musty smell and wine.
For storage characteristics of sorghum, it is necessary to do a good job of storage, must reduce its moisture content and cold storage. When storage, do a good number of times, dry and wet storage separately. Practice has proved that as long as we do a good job of drying, cleaning and drying after the sun work, and then use the natural ventilation and cooling in winter, sealed storage before the spring, generally can be safe summer.
(E) Soybean and soybean oil
1. Storage Characteristics of Soybeans (1) Soybeans have strong hygroscopicity. Soybeans are easy to grow and have a thin seed coat, a large germination hole, and a stronger moisture absorption capacity than wheat and corn. After soaking in dampness, soybeans expand in volume and are extremely prone to mildew. At the beginning, the beans were soft, the seed coat was dark and white, and there was a slight odor. Then the beans swelled and deformed, the umbilical reddened, and the crushed grains appeared colony, and the quality deteriorated rapidly.
(2) Soybeans are easy to go oil, change the soybeans stored in high temperature seasons, often appear two pieces of cotyledons red color by the umbilicus, after the cotyledon red deepened and expanded, severe oil immersion, while the high temperature and humidity also make the soybean sprout Reduced power. After the soybean oil changed, the oil yield was reduced, the color of the soybean oil was deepened, and the bean curd had a rancid odor and the red color of the soybean milk was made.
2. Storage of Soybeans (1) Strictly Controlled Water Storage Soybeans can not store more than 12% of water for long-term storage. After the soybeans are harvested, they must be fully dried in the pods and then threshed. Soybeans with high moisture content after storage can be treated with sunlight, but they must be cooled before they can be put into storage.
(2) Timely ventilation, heat dissipation and wetness The uneven moisture content in the newly-deposited soybean grains, coupled with the after-ripening effect of soybeans, the accumulation of hot and humid easily in the heap, causing fever and mildew, so timely ventilation, heat dissipation and wet.
(3) After low-temperature sealed storage, ventilation and cooling should be strengthened after entering the winter. Before the spring is warm, it can be sealed and sealed by plastic film or plastic film. It is generally safe in summer.
3. Soybean Oil Storage During storage, soybean oil is susceptible to deterioration and deterioration due to moisture, impurities, environmental air, light, and temperature. Therefore, the storage of soybean oil must be as much as possible to reduce the content of water and impurities, stored in a sealed container, placed in a place protected from light and low temperatures. The usual practice is to clean and dry the equipment before putting the oil into storage or loading the barrel. At the same time, the oil product, miscellaneous content and acid price must be carefully inspected. Only those that meet the safe storage requirements can be loaded into the warehouse. The content of water and impurities in soybean oil should not exceed 0.2%, and the acid value must not exceed 4. Bottled oil should not be too little or too little. After installation, the rubber lid or hemp must be placed under the lid to tighten the lid to prevent rain and air intrusion. At the same time, the name, grade, tare weight, net weight and barreling date of the oil should be indicated on each barrel in a timely manner so as to classify and store new items. It is advisable to store the barreled oil in a stacking warehouse. If it is to be stacked in the open air, the bottom of the barrel should be covered with wooden blocks so that they are inclined and the mouth of the barrel is leveled to prevent the rust on the bottom of the barrel and the rainwater from dripping from the barrel; Shed shade to prevent heat rancidity; in the cold winter season, no matter in the open air or in the store, paddy drums such as rice straw and chaff must be used to enhance insulation and prevent the oil from solidifying.
(6) Rapeseed and rapeseed oil
1. Rapeseed storage characteristics and methods Rape grains are small and thin, with large contact area with air, it is easy to absorb moisture. It is easy to sprout, heat, and mold during storage. If the moisture content is more than 13%, rapeseed can often be mildewed for only a day or night. The temperature rises above 50°C. All the grain surfaces are covered with colonies and become gray, which greatly reduces the quality. Therefore, storage of rapeseed must be fully dried before storage, so that the moisture control in the 9% to 10% or less. Rapeseed storage must be stacked according to the size of the water and quality. The average water content is less than 9%, and the rapeseed with no more than 5% of impurities is suitable for long-term storage. It can be piled 1.5-2 meters high and packed in 12-packs; the water content is between 10% and 12% of rapeseed, which is 1 meter high in bulk. , Packaging 6 ~ 8 package high, and can only short-term storage; moisture more than 12% of rapeseed should pay close attention to treatment, otherwise it may be heated at any time mildew. If the rapeseed harvest coincides with the plum rain season, natural oxygen-deficient storage can be sealed with plastic film. If necessary, low-dose aluminum phosphide tablets can also be placed in the sealed rapeseed heap for chemical storage. But both methods can only be used as a temporary emergency measure.
2. The rapeseed oil storage rapeseed oil storage method is basically the same as soybean oil. It is worth noting that the machine extract of rapeseed oil has a dark yellow color and is not green and has a high degree of transparency. The orange mustard oil has a yellow-orange green color and poor transparency. Regardless of the squeezed, pressed rapeseed oil, it must be filtered or precipitated before entering the warehouse to remove water and impurities before long-term storage.
(7) Peanut and peanut oil
1. The storage characteristics of peanuts (1) intolerant to low-temperature peanuts, such as large water, easily frozen at -3 °C, frozen peanuts, gray color, cotyledons become soft, rancid odor, reduce the germination rate.
(2) Non-high-temperature peanuts such as high-temperature drying or sun exposure, often easy to produce focal spots and split skin discoloration; storage at high temperatures is easy to go oil rancidity, lower quality.
(3) It is easy for moldy peanuts to have a moisture content of more than 10%, and for peanuts to have a moisture content of more than 8%. When it enters a hot season, it is prone to mildew, and even molds such as Aspergillus flavus will multiply, producing toxins and poisoning peanuts.
2. How to Store Peanuts (1) Peanuts The peanuts can be stored in the warehouse or in the open air. As long as the moisture is controlled within 9% to 10%, it can be stored for a longer period of time. In winter, peanuts with large water content but no more than 15% can be stored in small open pits. After being ventilated and dehumidified in winter, they will be stored in the warehouse until the next spring. Peanuts with moisture exceeding 15% will suffer frostbite if the temperature is too low, and must be stored after reducing the moisture content. Peanut fruit storehouses are sealed in bulk, with moisture below 9%, and the temperature does not exceed 28°C. Generally, they can be stored for a longer period of time.
(2) The storage, storage, and storage of peanuts in peanuts should effectively control the three stages of drying, freezing, and sealing.
1 Control Water Peanuts The safe water for long-term storage is 8%; the basic safety of water is less than 9%; the water can be stored in the short term in the winter of less than 10%; the water must be treated in time for more than 10%, and it cannot be stored for a long time.
2 Keep low-temperature moisture below 8%, and the temperature does not exceed 20°C for long-term storage. Above this temperature limit, fatty acids increase significantly, causing rancidity.
3 Closed storage and confinement can prevent pest infections and the influence of external temperature and humidity, and is conducive to keeping the temperature low. It is the main way of keeping peanuts.
3. Peanut oil is stored in the same manner as soybean oil. Since peanut oil contains more saturated fatty acids and is more easily solidified, it will generally increase in concentration below 5°C and be opaque at -3°C. If the temperature is too low, it will solidify, solidify the oil and then melt, and it is easy to oxidize. Increase the acid price. Therefore, peanut oil should pay attention to insulation in winter. In addition, peanut oil is a non-drying oil and it is not easy to form a thin film when exposed to air, which is advantageous for storage.
(8) Other oils and fats
1. The storage of cottonseed and cottonseed oil (1) The storability of graded storage of cottonseed has a great relationship with the harvest period. Cotton picked before the frost, cottonseed husks, strong, full kernels, low moisture, plush long, easier to store; after the frost picking cotton, soft and dry kernels, generally larger water, these two types of cottonseed to be stored separately .
(2) Open-air heaping of cottonseeds can be stored in the open air or in the bin. Since the cottonseed has the characteristics of open storage, it is widely used in the cotton-producing areas for open storage, but it is appropriate to store the cottonseeds as seed for storage. The open-air stacking sites require flat, dry, ventilated, well-drained conditions, and work well. The shape of the stack is generally rectangular at the bottom and oval at the top, with a large pile of 200,000 kilograms, a small pile of 100,000 kilograms, and about 260 kilograms per cubic meter of seed.
(3) The storage method of cottonseed oil is generally the same as that of soybean oil, but its quality requirement for safe storage is that, regardless of whether the refined or fluffy oil, the moisture content should be below 0.2%. The impurity content of refined cotton oil does not exceed 0.1%, and the acid value does not exceed 1. Wool oil impurities do not exceed 0.3% and the acid value does not exceed 8.
2. Storage of sesame and sesame oil (1) Sesame Seeds The storage of sesame seeds is small, the oil content is high, and the removal of impurities is more difficult. It is easily hygroscopic and feverish, and the rancidity deteriorates. Therefore, storage of sesame should strictly control the water and impurities. Practice has proved that bulk sesame moisture is less than 7.5% and impurities do not exceed 1%. Generally, it can be safely stored. Moisture content is between 7.5% and 8%, although it can only be stored for short periods in winter. Sesame seeds with a moisture content or impurity content within the safety standard should be sealed in bulk. Closed storage of sesame seeds, the quality of change is very small, the oil yield is higher than the stored sesame.
(2) Storage of sesame oil Sesame oil contains natural antioxidants such as sesamol and tocopherol, which are less susceptible to oxidative rancidity than ordinary oils. However, natural antioxidants are easily damaged by heat during processing, so management must be strengthened during storage. When storing in storage, water and impurities should not exceed 0.2% and the acid value should not exceed 4 to 5. Its storage method is similar to that of soybean oil.
(I) Rice and Rice Rice is one of China's major food crops and has a long history of cultivation. In our country since the Northern Song Dynasty, its output has been at the top of the grain. Rice production in Asia accounts for about 95% of the world's total rice production, China accounts for 35%, and rice production ranks first in the world. The main producing areas of rice in China are distributed in the Yangtze River and Pearl River basins. According to statistics, rice production in Sichuan, Hunan, Hubei, Guangdong, Jiangsu, Zhejiang, Anhui and Jiangxi accounts for more than 70% of the country's total rice production.
1. Storage characteristics of rice (1) Rice kernels have a complete rice husk protection, and have a certain resistance to the damage of insects and mildew and the influence on the humidity and heat. Therefore, rice has better storage stability than normal finished food.
(2) Rice has a short ripening period and is prone to sprouting. Generally, there is no obvious ripening period of japonica rice, and the ripening period of japonica rice is only about 4 weeks. The water needed for germination of rice is the least compared with other foods. When the water content of rice is more than 25%, germination can take place as long as the temperature is appropriate. Therefore, whether paddy is stored in the field, in the drying area or after storage, the paddy can germinate as long as it is exposed to rain, condensation on the grain surface, and moisture, and its water content reaches 25% or more. Wherever rice with sprouts is produced, even if it is dried, its storage stability, nutritional quality and food quality will be reduced.
(3) Rice is easy to age. After high temperature in summer, rice is often aged, and the fatty acid value is increased, and the germination rate is decreased. Among them, japonica rice is more stable than indica rice, and japonica rice is the worst. The new rice harvested within one year has a strong respiration effect. Later, it is similar to the decrease in enzyme activity, and the dehydration of rice colloids degrades the water absorption and decreases the hardness of the rice. Therefore, the storage stability is enhanced and it is advantageous for long-term storage. However, in the long-term storage, every time a high temperature season occurs, its seed quality and food quality decline year by year. Therefore, rice storage should pay attention to storage and storage.
(4) The resistance to high temperature is weak. The colloidal structure of rice is loose and every time it passes through high temperature or heat, it will cause deterioration of quality. When the paddy was harvested without timely threshing and drying, the temperature was raised to 60°C and the grains began to turn yellow. Grains are yellow, also known as yellow rice, yellow rice. If the temperature rises to 70°C, the grains will all turn yellow. During the storage of rice, the greater the number of fevers, the faster the rate of yellowing increases. With the extension of the storage period, although it is not heated and mildew, it will increase yellowing. After 2 years of storage, the rate of yellowing is 5% or less, storage is 3 to 7 years, and yellow grains account for 5% to 10%.
(5) Pests that harm rice include corn elephants, rice elephants, valley fools, wheat moths, tyrants of grain, and sawtooth. After the spring season every year, the pests begin to breed in about April to May. The peak season occurs in the annual high temperature season.
(6) The vast majority of microorganisms attached to rice are mesophilic, mesozoic and aerobic microorganisms. High-moisture rice fever is caused by actinomycetes, bacteria, yeasts, and molds such as Rhizopus and Mucor. Low-moisture rice mildew is caused by the activity of dry fungi such as Aspergillus niger. of.
2. Storage method of paddy (1) Strictly control the quality of paddy in the newly imported rice, the impurity does not exceed 0.5%, and the moisture does not exceed 13.5%. The safe moisture of japonica rice in storage can be relaxed by 0.5% to 1% compared with japonica rice. The control of grain moisture content within safe moisture is the primary measure to ensure the safety of stored grain. Therefore, whether it is for grain banks or for farmers, it is very important to strictly control grain quality.
(2) Strengthen the resistance of Tongfeng cooling paddy to high temperature, the grain temperature is high, the speed of quality deterioration is fast, especially when the summer grain is put into storage, it is during the high temperature season. It is necessary to use mechanical ventilation to disperse the wet and heat in the valley heap in time. After the autumn rice is put into storage, it is necessary to seize the opportunity to make full use of the cold weather in winter and reduce the grain temperature. While cooling, it is necessary to prevent condensation on the grain surface.
(3) Closed storage at a proper time For generally low-moisture rice, the moisture-proof work must be completed before the spring season. Confined storage can delay the rise of grain temperature, which is conducive to safe summer.
(4) After storage of summer grain, natural anaerobic storage, double-low storage or slow-release fumigation technology can be adopted. That is, in the sealed grain heap, the dosage of 2-3 grams of aluminum phosphide per cubic meter and 0.07 mm of polyethylene can be used. The film is made into a pouch to wrap the drug and is then buried in the upper layer of the grain heap until the phosphine is slowly released to prevent pests and inhibit the occurrence of microorganisms.
(5) The storage and disinfection of warehouses and equipment should be well done when rice is in storage. Attention should be paid to the prevention of pest infections during storage and after storage. Once pests are found, measures must be taken to eliminate them.
3. The storage characteristics of rice The rice was shelled to obtain brown rice, and the brown rice was then ground to peel and embryo to become rice. Since rice is not protected by the chaff, the endosperm is directly exposed to space and is susceptible to external factors. Therefore, rice has poor storage stability and is far more difficult to store than rice.
(1) Rice is easy to absorb moisture and return moisture, causing rice to hydrophile. Hydrophilic colloids (starch, protein) are directly in contact with air and easily absorb moisture. Under the same conditions of temperature and humidity, balanced rice moisture is higher than rice. At the same time, wolfberry powder in rice not only has strong moisture absorption but also a large number of microorganisms, which easily causes fever, mildew, deterioration, and taste deterioration.
(2) Rice is easy to explode Irregular cracks in rice are called waist bursts. The reason why rice is popped is that because of the rapid drying of rice grains, the outer layer of rice grains dries faster, the water inside the rice grains shifts outward slowly, the drying rates of the inner and outer layers are different, the volume shrinkage is different, the outer layer shrinks, and the inner layer shrinks. The shrinkage is small and it causes a crash. In addition, rice grains can also cause a crash in the case of rapid absorption of moisture. When the rice is bursting, the broken rice becomes thick and sticky, which affects the quality of the food.
(3) Easy aging As the storage time is extended, the rice is gradually aged. When it is aged to a certain degree, Chen Mi smells, and at the same time, it changes taste. In addition to losing the original flavor of rice, it also shows that the gloss of rice is darkened, the viscosity of rice is reduced, and the hardness is increased.
(4) Easy to gray rice During the storage period, if the outside environment is high in humidity or the original water of the rice is high, ashing will occur. That is, the rice grain loses its original luster, and the surface of the grain of rice exhibits grayish-powdered crumbs and Baidao grooves, which is a precursor to the deterioration of the rice.
(5) Pest-prone pests The major pests that injure rice include rice figurines, corn elephants, tyranolium, rice flatworms, and long-horned flat gorillas.
4. The method of storage of rice (1) Conventional storage mainly uses the method of drying, natural low temperature, and confinement, and the rice of the processed machine is cooled to the temperature of the storage before being stored in the stack. High-moisture rice can be stored in short-term storage after ventilation, or it can be stored in cool and dry condition after ventilation.
(2) Low-temperature storage Low-temperature storage is an effective way to preserve rice. Using low natural temperatures, the low-water rice is processed in winter. After cooling, the rice is stored in a cool store. Using appropriate moisture-proof and heat-insulating measures, rice is kept at a low temperature for a long period of time. When the food temperature is relatively prolonged, rice is safe. An effective method. Using mechanical refrigeration to keep rice cool during the summer can also make rice safe. However, due to the large investment in refrigeration equipment and plant construction, it has not been fully promoted.
(3) Atmosphere storage For packaged or bulk rice, sealed with plastic film, use the respiration of rice and microorganisms in the grain heap, reduce oxygen naturally, or store carbon dioxide or nitrogen, which has good insecticidal and antibacterial effects. It can also be stored in hibernation in small packages, with 3 to 5 kilograms of rice per bag. It can be stored fresh in CO2 and can be safely stored for more than 1 year.
(4) chemical storage in sealed rice piles, according to the dose of aluminum phosphide 2 ~ 3 g / cubic meter, using 0.07 mm polyethylene film made of small bags into 15 ~ 20 grams of aluminum phosphide tablets, hung in Sealed bags are piled or embedded in the upper layer of the packaged grain to allow the slow release of phosphine, which can kill insects, inhibit bacteria and prevent rice from mildew.
(b) Wheat and flour Wheat is a staple food worldwide. China's wheat production is second only to rice. The main producing areas are south of the Great Wall and the Huanghuai Plains north of the Yangtze River, including Henan, Shandong, Hebei, southern Shanxi, Guanzhong in Shaanxi, and northern Jiangsu and Anhui.
1. Characteristics of storage of wheat (1) Long maturation period The ripening period of wheat is relatively obvious. It takes a few weeks or even 2 to 3 months for newly harvested wheat to complete the ripening period. The ripening effect of wheat is mainly manifested in its strong breathing ability. After the new wheat is put into the warehouse, due to the strong physiological metabolism, it is easy to cause sweating and warming of the grain piles. If no inspections are found and measures are taken in time, it will cause the grain surface to be moldy and rotten.
(2) Heat-resistance Wheat has high heat-resistance, and its protein and respiratory enzymes have high heat resistance. After a certain high temperature of wheat, it will not only lose its vitality, but also improve its quality. The use of the characteristics of wheat heat resistance, hot sealed storage, can kill insects, mold.
(3) Strong hygroscopicity The seed coat of wheat is thin, contains a large amount of hydrophilic substances, and easily absorbs the moisture in the air. In the same relative humidity, the balanced moisture of wheat is always higher than that of rice. The hygroscopicity of wheat is different because of different varieties. The cortex of red wheat is thicker and the moisture absorption is slower. White wheat has thinner cortex and stronger hygroscopicity; soft wheat has stronger moisture absorption ability than hard wheat.
(4) Weak Breathing Power Wheat's respiration after the ripening period is weak, and it is lower than that of other cereals. Red wheat has lower respiratory intensity than white wheat. Therefore, wheat has better storability and can maintain good quality for 2 to 5 years under normal conditions.
(5) Vulnerable to pests Because wheat has no shell protection, the cortex is thin, and the new wheat is in high temperature season for storage, which is suitable for breeding pests. The pests that harm wheat are mainly corn elephants, wheat moths, Indian rice bran, and Otani thief.
2. Method of storage of wheat (1) Thermally sealed storage method Heat-sealed storage of wheat can prevent pests and molds, promote the postharvest action of wheat, and increase the germination rate. The specific method is: use summer high-temperature exposure of wheat, pay attention to grasp the principle of late harvest, thin and diligent, in the barley temperature above 42 °C, preferably 50 ~ 52 °C, maintain 2 hours, and then quickly put the stacking, After the grain surface is leveled, the surface of the grain is covered with hot mats, straw curtains, etc., and the doors and windows are insulated. To do a good job of heat-sealing and storage, the first requirement is that the moisture content of wheat should be reduced to 10% to 12%. Secondly, sufficient temperature and closed time are required. After entering the warehouse, the grain temperature should be about 46°C and closed for 7 to 10 days. When the temperature is around 40°C, it must be sealed for 2 to 3 weeks.
(2) Low-temperature storage method Low-temperature storage is the basic approach for safe storage of wheat. Although wheat has high temperature resistance, it will continue to be stored at high temperatures and will reduce its quality. The low temperature storage can maintain the quality and germination rate. According to reports, wheat has been stored for 16 years under low-temperature, low-oxygen conditions and its quality has changed little, and it can be made into good bread. Using low temperature in winter, natural ventilation, mechanical ventilation and cooling, and then chilling and confining, will eliminate overwintering pests and delay the impact of high temperature on the outside, with good results. In addition, the use of underground storage of wheat can also delay the deterioration of wheat quality.
(3) Natural Hypoxia Storage The most widely used method at home and abroad is natural hypoxia storage. For the newly-introduced wheat, due to the effect of post-harvest, the physiological activity of wheat is strong and the respiratory intensity is high, which is extremely beneficial to the natural oxygen reduction of the grain heap. Practice has proved that as long as the closed work is done well, after 20 to 30 days of natural anoxic wheat, the oxygen concentration can be reduced to 1.8% to 3.5%, which can achieve pest control. The purpose of anti-mildew. If it is Chenmai every other year, the subsequent ripening effect has already been completed, and it enters a deep dormant state, the respiratory intensity is very weak, and it is not appropriate to carry out natural hypoxia. At this time, microbiological assisted oxygen reduction or charging of carbon dioxide and nitrogen into the wheat heap can be adopted. Meet the requirements of the atmosphere.
3. Flour storage characteristics (1) Hygroscopicity, poor storage stability Flour moisture higher than wheat, flour processing in summer than winter processing of high moisture, the actual moisture when stored in 13% to 14%, because the flour is a particulate structure, It has a large area of ​​activation and a faster rate of moisture absorption than wheat, so the flour tends to return to moisture in high humidity conditions. Flour is hot and mildew, mainly due to the high moisture content of the flour, or the respiration of the flour particles and the respiration of the microorganisms caused by the moisture absorption of the flour.
(2) The Yicheng Unity Block flour stack is stored for a period of time, and the lower layer is pressed into a mass due to the influence of the middle and upper layer pressure. The pressed flour is agglomerated and adhered with sterile silk. After being loosened and rubbed loosely, it can return to normal after leaving the warehouse and has no major impact on quality. However, if agglomeration occurs due to heat and mildew, it is not easy to restore looseness and quality is significantly reduced.
(3) The familiar and white flour of flour is stored for about 10 to 30 days after being stored in the warehouse. The quality is improved, the gluten strength is enhanced, the fermentation is good, the bread is made large and loose, the noodle is even and uniform, and the taste is soft. The delicious, gluten-improved effect is known as the maturation of flour. In addition, the flour is stored for a certain period of time, and the color of the flour gradually fades to white due to a slight yellowish color at the time of the first discharge, which is due to oxidation of the fat-soluble pigment in the flour. The nutritional properties of flour have not improved, but have also been reduced.
(4) The change of flour sour and bitter fatty acids is the main indicator of deterioration of flour quality. Even with the normal moisture content of flour, because of the hydrolysis of fat, the fatty acid increases regularly and the acid value increases; the flour with higher moisture content, due to the adverse effects of microorganisms, causes the accumulation of water-soluble organic acids, and the decomposition of fat causes the acid price. Increase faster. Wheat that has sprouted or overheated is made into flour and its rancidity is faster than normal flour.
4. Flour storage method The main technical measures for flour storage are to do a good job of confining moisture, stacking and preventing pests. The safe storage of flour is controlled within 13%.
(1) Closed moisture-proof flour is easy to absorb moisture, so moisture protection is very important. After the flour is put into storage, the plastic film should be sealed on the six sides. This will not only prevent moisture absorption, but also prevent insects and mildew infections. It can also keep fresh and dust-proof. For flour that needs to spend the rainy season, it is necessary to close the moisture barrier as soon as possible.
(2) Reasonable stacking For freshly processed flour, piles can be piled up first and then changed into large piles after cooling and loosening. In the dumping operation, only the upper and lower positions can be changed, and the original flour in the outer layer should still be placed in the outer layer so as to avoid putting the flour with large moisture content into the core, causing heat and mildew. In addition, due to the impatience of flour storage, it is necessary to combine the sales situation and promptly change positions.
(3) Strictly Preventing Pests Pests Fighting flour pests include tyrants, horned crows, and maggots. Pests often occur at the mouth of bags. Before entering the warehouse, the flour must be cleaned and disinfected as well as disinfected and disinfected. After storage, strict management is required. Once pests are found, they are treated with fumigation in a timely manner and sieved mechanically or manually to screen worms for sale. In addition, aluminum phosphide can be used for preventive fumigation according to actual conditions.
(three) corn and corn flour
1. The storage characteristics of corn (1) Large corn embryos, strong breathing, corn embryos, accounting for almost 1/3 of the total grain size, accounting for about 10% to 12% of the total grain weight. Since the embryos absorb moisture easily and contain a large amount of unsaturated fatty acids, they are prone to mildew when the storage environment is high in temperature and humidity. The fatty acid value of the corn embryo is always higher than that of the endosperm, and the rancidity begins with the embryo.
(2) The original corn has large moisture and uneven maturity. China's corn production areas are in the north, and when the corn harvests every year, the weather is cold, so the newly harvested corn moisture is 20% to 35%. Due to the same spikes, different pollination time at the top and base, leading to uneven corn kernel maturity, and corn being vulnerable to damage during threshing, so that the presence of immature and broken kernels increases the difficulty of corn storage.
(3) Easy-to-yield corn Due to the large size of the embryo, the fat content is high and the amount of bacteria is large. When the temperature and moisture conditions are appropriate, mildew easily occurs.
(4) Pests that are more likely to infect pests are more harmful to corn, including corn elephants, Dagu Pirates, Hexagrams, Pirates of the Valley, Indian pimple, whiteflies and wheat moths. Insect pests generally harm the embryos first. If Wangmi is infected with pests, it is much more serious than other grain types.
2. The storage method of corn In our country, the storage of corn in the north is mainly based on mildew, and in the south is mainly pest control. There are two kinds of storage methods for corn: grain storage and panicle storage. The national corn storage is grain storage, and most of the farmers use the pan-Tibetan method.
(1) Head and ear panicles The ear panicle is a typical ventilated ear reservoir. In North China and Northeast China, the high-moisture maize ear reservoir has great advantages due to the low temperature when harvesting corn. After a winter of natural ventilation, the moisture of corn in the coming April to May can be reduced to 12% to 14%.
(2) The first step in grain storage is to control the moisture in corn storage, requiring the moisture content of stored corn to be less than 13%. In addition, it can be used for hypoxia storage according to the characteristics of large corn embryos and strong breathing. Need to use double low storage, three low storage methods or the use of slow release fumigation method and other comprehensive methods of storage, to prevent corn heap fever, mildew, insects.
3. The storage characteristics and methods of corn flour are often washed with water during processing to increase the moisture content. Newly-opened corn meal has a higher temperature, generally 30 to 35°C. The high temperature and large moisture create conditions for the growth and reproduction of microorganisms. Maize meal has high fat content and is susceptible to oxidative deterioration. Therefore, corn flour is not easy to store finished grain, easy to mold, rancid bitter, not long-term storage.
During the storage of corn flour, the moisture content must not exceed 14%. In addition, corn flour should not use a large number of scattered methods, generally with bags, code into a ventilation rake, and 5 to 7 days dumping 1 times, the principle of dumping the same with the dumping of flour. If there is agglomeration, it should be kneaded in time. When conditions permit, it is best to use low temperature storage or modified atmosphere storage.
When processing corn flour, it is best to go to the embryo and then milling, so that it can extract corn embryo oil, increase economic efficiency, but also improve the silty, is conducive to storage.
(D) Other coarse grains
1. Barley's storage characteristics and methods Barley's acreage and yield ranks fourth in all grain species in China. Barley is processed and ground to make barley flour, which can be made into scones, made of barley paste, or blended with wheat flour to make other foods. In addition to food, barley is the main raw material for beer, alcohol, maltose and other products.
The physical, chemical and storage characteristics of barley are similar to that of wheat, and the storage methods are basically the same. Only the barley used in industry is used for germination. Therefore, the barley for industrial use should pay special attention to maintain its germination power. Barley can also be stored in a heat-tight manner, but the high-temperature sealing time cannot exceed 1 month, otherwise it will affect its germination power and reduce economic value.
2. The storage characteristics and methods of sorghum sorghum in our country's output ranks fifth in all grain species, is one of the staple food in northern China. Sorghum is not only edible, but also an important raw material for wine making, sugar making, making soy sauce, and vinegar.
The skin of sorghum is horny, the seed coat contains tannin, and it has a mildew-proof effect, which is favorable for storage. However, sorghum is often more miscellaneous, and is harvested in late autumn in northern producing areas. The temperature is low, and it is not easy to dry. The sorghum moisture of new storage is generally 16% to 25%, and it is still prone to mildew, causing the grain to turn dark brown or Black, with a strong musty smell and wine.
For storage characteristics of sorghum, it is necessary to do a good job of storage, must reduce its moisture content and cold storage. When storage, do a good number of times, dry and wet storage separately. Practice has proved that as long as we do a good job of drying, cleaning and drying after the sun work, and then use the natural ventilation and cooling in winter, sealed storage before the spring, generally can be safe summer.
(E) Soybean and soybean oil
1. Storage Characteristics of Soybeans (1) Soybeans have strong hygroscopicity. Soybeans are easy to grow and have a thin seed coat, a large germination hole, and a stronger moisture absorption capacity than wheat and corn. After soaking in dampness, soybeans expand in volume and are extremely prone to mildew. At the beginning, the beans were soft, the seed coat was dark and white, and there was a slight odor. Then the beans swelled and deformed, the umbilical reddened, and the crushed grains appeared colony, and the quality deteriorated rapidly.
(2) Soybeans are easy to go oil, change the soybeans stored in high temperature seasons, often appear two pieces of cotyledons red color by the umbilicus, after the cotyledon red deepened and expanded, severe oil immersion, while the high temperature and humidity also make the soybean sprout Reduced power. After the soybean oil changed, the oil yield was reduced, the color of the soybean oil was deepened, and the bean curd had a rancid odor and the red color of the soybean milk was made.
2. Storage of Soybeans (1) Strictly Controlled Water Storage Soybeans can not store more than 12% of water for long-term storage. After the soybeans are harvested, they must be fully dried in the pods and then threshed. Soybeans with high moisture content after storage can be treated with sunlight, but they must be cooled before they can be put into storage.
(2) Timely ventilation, heat dissipation and wetness The uneven moisture content in the newly-deposited soybean grains, coupled with the after-ripening effect of soybeans, the accumulation of hot and humid easily in the heap, causing fever and mildew, so timely ventilation, heat dissipation and wet.
(3) After low-temperature sealed storage, ventilation and cooling should be strengthened after entering the winter. Before the spring is warm, it can be sealed and sealed by plastic film or plastic film. It is generally safe in summer.
3. Soybean Oil Storage During storage, soybean oil is susceptible to deterioration and deterioration due to moisture, impurities, environmental air, light, and temperature. Therefore, the storage of soybean oil must be as much as possible to reduce the content of water and impurities, stored in a sealed container, placed in a place protected from light and low temperatures. The usual practice is to clean and dry the equipment before putting the oil into storage or loading the barrel. At the same time, the oil product, miscellaneous content and acid price must be carefully inspected. Only those that meet the safe storage requirements can be loaded into the warehouse. The content of water and impurities in soybean oil should not exceed 0.2%, and the acid value must not exceed 4. Bottled oil should not be too little or too little. After installation, the rubber lid or hemp must be placed under the lid to tighten the lid to prevent rain and air intrusion. At the same time, the name, grade, tare weight, net weight and barreling date of the oil should be indicated on each barrel in a timely manner so as to classify and store new items. It is advisable to store the barreled oil in a stacking warehouse. If it is to be stacked in the open air, the bottom of the barrel should be covered with wooden blocks so that they are inclined and the mouth of the barrel is leveled to prevent the rust on the bottom of the barrel and the rainwater from dripping from the barrel; Shed shade to prevent heat rancidity; in the cold winter season, no matter in the open air or in the store, paddy drums such as rice straw and chaff must be used to enhance insulation and prevent the oil from solidifying.
(6) Rapeseed and rapeseed oil
1. Rapeseed storage characteristics and methods Rape grains are small and thin, with large contact area with air, it is easy to absorb moisture. It is easy to sprout, heat, and mold during storage. If the moisture content is more than 13%, rapeseed can often be mildewed for only a day or night. The temperature rises above 50°C. All the grain surfaces are covered with colonies and become gray, which greatly reduces the quality. Therefore, storage of rapeseed must be fully dried before storage, so that the moisture control in the 9% to 10% or less. Rapeseed storage must be stacked according to the size of the water and quality. The average water content is less than 9%, and the rapeseed with no more than 5% of impurities is suitable for long-term storage. It can be piled 1.5-2 meters high and packed in 12-packs; the water content is between 10% and 12% of rapeseed, which is 1 meter high in bulk. , Packaging 6 ~ 8 package high, and can only short-term storage; moisture more than 12% of rapeseed should pay close attention to treatment, otherwise it may be heated at any time mildew. If the rapeseed harvest coincides with the plum rain season, natural oxygen-deficient storage can be sealed with plastic film. If necessary, low-dose aluminum phosphide tablets can also be placed in the sealed rapeseed heap for chemical storage. But both methods can only be used as a temporary emergency measure.
2. The rapeseed oil storage rapeseed oil storage method is basically the same as soybean oil. It is worth noting that the machine extract of rapeseed oil has a dark yellow color and is not green and has a high degree of transparency. The orange mustard oil has a yellow-orange green color and poor transparency. Regardless of the squeezed, pressed rapeseed oil, it must be filtered or precipitated before entering the warehouse to remove water and impurities before long-term storage.
(7) Peanut and peanut oil
1. The storage characteristics of peanuts (1) intolerant to low-temperature peanuts, such as large water, easily frozen at -3 °C, frozen peanuts, gray color, cotyledons become soft, rancid odor, reduce the germination rate.
(2) Non-high-temperature peanuts such as high-temperature drying or sun exposure, often easy to produce focal spots and split skin discoloration; storage at high temperatures is easy to go oil rancidity, lower quality.
(3) It is easy for moldy peanuts to have a moisture content of more than 10%, and for peanuts to have a moisture content of more than 8%. When it enters a hot season, it is prone to mildew, and even molds such as Aspergillus flavus will multiply, producing toxins and poisoning peanuts.
2. How to Store Peanuts (1) Peanuts The peanuts can be stored in the warehouse or in the open air. As long as the moisture is controlled within 9% to 10%, it can be stored for a longer period of time. In winter, peanuts with large water content but no more than 15% can be stored in small open pits. After being ventilated and dehumidified in winter, they will be stored in the warehouse until the next spring. Peanuts with moisture exceeding 15% will suffer frostbite if the temperature is too low, and must be stored after reducing the moisture content. Peanut fruit storehouses are sealed in bulk, with moisture below 9%, and the temperature does not exceed 28°C. Generally, they can be stored for a longer period of time.
(2) The storage, storage, and storage of peanuts in peanuts should effectively control the three stages of drying, freezing, and sealing.
1 Control Water Peanuts The safe water for long-term storage is 8%; the basic safety of water is less than 9%; the water can be stored in the short term in the winter of less than 10%; the water must be treated in time for more than 10%, and it cannot be stored for a long time.
2 Keep low-temperature moisture below 8%, and the temperature does not exceed 20°C for long-term storage. Above this temperature limit, fatty acids increase significantly, causing rancidity.
3 Closed storage and confinement can prevent pest infections and the influence of external temperature and humidity, and is conducive to keeping the temperature low. It is the main way of keeping peanuts.
3. Peanut oil is stored in the same manner as soybean oil. Since peanut oil contains more saturated fatty acids and is more easily solidified, it will generally increase in concentration below 5°C and be opaque at -3°C. If the temperature is too low, it will solidify, solidify the oil and then melt, and it is easy to oxidize. Increase the acid price. Therefore, peanut oil should pay attention to insulation in winter. In addition, peanut oil is a non-drying oil and it is not easy to form a thin film when exposed to air, which is advantageous for storage.
(8) Other oils and fats
1. The storage of cottonseed and cottonseed oil (1) The storability of graded storage of cottonseed has a great relationship with the harvest period. Cotton picked before the frost, cottonseed husks, strong, full kernels, low moisture, plush long, easier to store; after the frost picking cotton, soft and dry kernels, generally larger water, these two types of cottonseed to be stored separately .
(2) Open-air heaping of cottonseeds can be stored in the open air or in the bin. Since the cottonseed has the characteristics of open storage, it is widely used in the cotton-producing areas for open storage, but it is appropriate to store the cottonseeds as seed for storage. The open-air stacking sites require flat, dry, ventilated, well-drained conditions, and work well. The shape of the stack is generally rectangular at the bottom and oval at the top, with a large pile of 200,000 kilograms, a small pile of 100,000 kilograms, and about 260 kilograms per cubic meter of seed.
(3) The storage method of cottonseed oil is generally the same as that of soybean oil, but its quality requirement for safe storage is that, regardless of whether the refined or fluffy oil, the moisture content should be below 0.2%. The impurity content of refined cotton oil does not exceed 0.1%, and the acid value does not exceed 1. Wool oil impurities do not exceed 0.3% and the acid value does not exceed 8.
2. Storage of sesame and sesame oil (1) Sesame Seeds The storage of sesame seeds is small, the oil content is high, and the removal of impurities is more difficult. It is easily hygroscopic and feverish, and the rancidity deteriorates. Therefore, storage of sesame should strictly control the water and impurities. Practice has proved that bulk sesame moisture is less than 7.5% and impurities do not exceed 1%. Generally, it can be safely stored. Moisture content is between 7.5% and 8%, although it can only be stored for short periods in winter. Sesame seeds with a moisture content or impurity content within the safety standard should be sealed in bulk. Closed storage of sesame seeds, the quality of change is very small, the oil yield is higher than the stored sesame.
(2) Storage of sesame oil Sesame oil contains natural antioxidants such as sesamol and tocopherol, which are less susceptible to oxidative rancidity than ordinary oils. However, natural antioxidants are easily damaged by heat during processing, so management must be strengthened during storage. When storing in storage, water and impurities should not exceed 0.2% and the acid value should not exceed 4 to 5. Its storage method is similar to that of soybean oil.
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