Nowadays, it is a lot of fresh fruit market season. Industry experts believe that the preservation of fresh fruit is one of the main means to meet the diversification, high quality, and no seasonality of agricultural products. In the case of continuous expansion of fruit planting areas and continuous expansion of production in China, the majority of fruit growers can only scientifically use this important link of cold storage and preservation, so as to better realize the post-production benefits of agricultural products. Fruit harvest time. Apple's harvesting period is determined first according to market demand and sales price. Sometimes before the fruit matures, a large number of merchants go ahead to acquire the fruit in order to seize the market. In this case, according to the market analysis of the previous year and the forecast of the current year's market, it would be worthwhile to collect and sell when it was deemed cost-effective. Sometimes merchants require that the fruit be acquired when it is fully mature. This will be based on the signing of the contract. Second, according to fruit use. If the fruit is harvested for long-distance transportation and storage, or for the processing of candied fruit, canned food, etc., it is advisable to harvest it at the middle of ripening. The fruit size has been set for a long period of time, but it has not yet fully matured. The flesh has a high hardness, and the proper flavor and aroma have not yet been fully demonstrated. If only the local market is provided, not long-distance transportation and long-term storage, or processing raw materials for fruit juices, jams, and fruit wines, it is advisable to harvest them during the ripening period. During this period, the fruits are fully mature, showing the color, flavor and nutritional value of the varieties. The highest, the best flavor. Then according to the weather conditions. If the meteorological department forecasts recent severe winds, storms, hail and other severe weather, it should be harvested in advance. To reduce economic losses. Harvesting method. At present, fresh fruit is still hand-picked, both in developed and developing countries. When picking, special tools such as picking baskets must be used to load the harvested apples into the turnover box and transport them to the graded packing site. The order of picking is from top to bottom, from outside to inside. The picking time is better in the lower temperature morning. Take care during harvesting to prevent mechanical damage. In order to improve the quality fruit rate, it is best to adopt a phased harvest, that is, the harvest of orchard fruit is divided into 2 to 3 times. For the first time, the main harvest was to collect the fruit on the periphery of the crown, with a large fruit at the top, and a good colored fruit; after about one week, picking the fruit with better coloring in the middle and lower part of the crown. When picking in stages, be careful not to bump or touch the fruit left on the tree. Graded packaging grading. Grading means that the fruit to be harvested is appropriately adjusted and divided into a number of neat categories according to relevant standards according to shape, size, color, texture, maturity, mechanical damage, pests and diseases, and other characteristics, so that the same category of fruit specifications and quality Consistent, achieve standardization of production and sales. At present, most of the apple producing areas still adopt the method of artificial grading, and the fruit size is usually determined by the grading board. There are different sizes of round holes with a difference of 5 mm from 60 mm to 100 mm per level on the classifier, which allows the fruit to be divided into several grades according to its size. The indicators such as fruit shape, color, and fruit surface cleanliness are completely determined by visual inspection and empirical judgment, and work efficiency is very low. Mechanical classification has been widely used in developed countries. The grading machine has a grading machine with a simple structure, that is, by the size of the fruit, several grades are separated by conveyor belts. There are also more advanced photoelectric grading machines that can determine the fruit color and can also separate the fruit weight. Machines with a high degree of automation can wash, dry, wax, gradate, weigh, and package at one time. The classification is accurate and the work efficiency is high. However, no matter how advanced the grading equipment, some workers are required to stand on the edge of the assembly line to check out the fruits that cannot be judged by the machines, such as scars and spots. Wash and wax. Washing the fruit is the use of soaking, rinsing, spraying or other methods of washing or brushing to remove dirt on the surface of the fruit to increase the value of the product. Apples produced by the bagging method can avoid the part of fruit washing because the fruit surface is clean. Waxing is the application of a thin, uniform, transparent film on the surface of the fruit, also known as a coating. After waxing the fruit, it not only inhibits its respiration, reduces water evaporation and consumption of nutrients, delays aging, but more importantly, it enhances the luster, beauty, and beauty of the fruit surface and increases the value of the product. This method is already an important measure for modern fruit marketing, mostly used for pre-marketing fruit processing, as well as for long-distance transportation and short-term storage. Waxing is generally performed after washing the fruit. The methods include manual dipping, brushing, and mechanical waxing. When a small amount of treatment is used, the fruit can be removed with a manual method in the prepared coating liquid, or the coating liquid can be evenly wiped on the fruit surface with a soft brush or a cotton cloth. When a large number of treatments are performed, mechanical peening wax has high work efficiency and good effect. Complete sets of equipment consist of soaking tanks, roller conveyors, cleaning and waxing machines, air dryers, and classifiers. The waxing paints mainly include emulsifying waxes, shellac waxes, fruit waxes and the like of paraffin waxes. package. Before packing, Apple should be carefully selected to ensure that the fruit is fresh, clean, free from mechanical injury, pests, and rot, and packed according to relevant standards. Packing should be carried out under cool ambient conditions to avoid wind, sun and rain. The fruit should be placed tightly and neatly in a certain arrangement in the packaging container. Between the inner wall of the container and the fruit layer, there must be paper or foam, corrugated board, tray and other cushions to avoid bumping or crushing the fruit. When packing and handling, handle it gently to avoid mechanical damage. Specify the product's trademark, product name, grade, specification, weight, number of grains, place of manufacture, specific mark, packing date, etc. outside the package. After the pre-chilled fruits were harvested from the trees, their temperature was higher due to the influence of the sun and the temperature, which resulted in a faster decrease in the hardness of the pulp, a shortened shelf life, and a reduced quality. Therefore, the fruit must be precooled as soon as possible after harvesting. The most primitive method of pre-cooling is to use the low temperature at night to reduce the fruit temperature after harvesting. The fruit is usually placed in a basket under the tree or shade, or the fruit is spread on the ground, exposed at night, shaded during the day, allowed to cool naturally, and then stored. However, this kind of pre-cooling method depends on the slow speed of natural cooling, which affects the quality of storage and preservation of fruits to a greater extent, and it is not appropriate to adopt such pre-cooling methods for controlled atmosphere storage and cold storage. At present, better pre-cooling methods mainly include low-temperature pre-cooling, ice-water pre-cooling, and vacuum rapid pre-cooling. Low temperature precooling. The harvested fruits were pre-cooled under ambient conditions around 0° C., gradually lowering the temperature to 1 to 2° C. Boxed (15 to 20 kilograms) apples should be placed in a single storey, with a pre-cooling temperature of 0°C and a pre-cooling time of 15 to 20 hours. Ice water precooling. Directly immersing the fruit in ice water at 0 to 1°C for 10 to 15 minutes, the fruit temperature can be brought to 1 to 2°C, but the water temperature must not rise above 2°C. Vacuum precooling. The fruit is placed in a vacuum rapid precooler and the temperature of the fruit can be reduced to the desired precooling temperature after 20 to 30 minutes. Vacuum pre-cooler, as long as the pressure dropped to 4.5 mm mercury column, the water temperature can reach 0 °C. This pre-cooled fruit can reach 0.3 ~ 1.5t. Other pre-cooling methods. The small cold storage area of ​​a typical apple producing place is especially a self-contained cold storage room. It adopts morning harvesting for timely storage and the evening harvesting of flat fruits to dry overnight. It is put in storage before 6 o'clock the next day. Apples in this period can generally reduce the field heat by 20% to 50%, and the energy saving effect is quite significant. The fresh cold storage built in or near the orchard can be harvested at low temperature and stored in phases. Atmosphere storage for controlled atmosphere storage is a technical measure to prolong the storage period of apples and obtain a good preservation effect by adjusting and controlling the gas composition of the storage environment. The standard air-conditioning library is a cold storage and sealing facilities and gas and gas conditioning equipment. Atmosphere storage and preservation technology points. Requirements for storing fruit: Air-conditioned apples should be of good quality and high quality. They are mainly supplied to domestic and foreign markets and supermarkets at home and abroad; any apples that undergo air-conditioning storage must be properly harvested, shipped, and carefully selected. Grading and packing are to be stored; the fruit should be stored in storage within 1 to 2 days after bin packing, and the longest should not exceed 3 days, otherwise it will affect the quality of the fruit. Fruit pre-cooling: Pre-cooling of apples before they are put into storage is a big problem that affects the shelf life and quality of the fruit. Fruits are stored without precooling after harvest, and fruit temperature is difficult to fall in the short term; therefore, post-harvest pre-cooling of fruits reduces the respiratory intensity of fruits, reduces the consumption of water and nutrients, and helps to improve storage stability. And preservation effect. Temperature and gas regulation: rapid storage, generally the storage of every 100t, the slowest time between the filling of the warehouse shall not exceed 48 hours; immediately after the closure of the library to quickly reduce oxygen; 2 to 3 days after the closure of the library, the library O2 drops 2% ~ 3%, CO2 concentration should not be higher than 5%, the temperature is constant at 0 °C up and down, relative humidity is maintained at about 90%. Air conditioning management. Before the apple is put into storage, it is necessary to carefully check whether the functions of the air-conditioning warehouse equipment are in good condition, whether it is operating normally, and eliminate various faults in time. The chiller was started and the temperature in the storage room was reduced to 0°C. After initial storage, when the storage temperature dropped to 0°C, the nitrogen generator and CO2 remover were started to perform rapid oxygen reduction and CO2 removal, so that the temperature and gas composition in the reservoir were gradually stabilized in the appropriate indicators for long-term storage. . Changes in the temperature and O2, CO2 concentration in the library should be measured 1 to 2 times a day, grasp the law of change, and strictly control. The management in the middle and later stages is mainly to inspect and inspect the work carefully and regularly so as to prevent the failure of various facilities in the warehouse. The air-conditioned storage of the apple must stop the operation of all the atmospheric adjustment equipment before exiting the warehouse. The oxygen is slowly increased by the small opening of the storage gate. After 2 to 3 days, the gas composition in the reservoir gradually returns to the atmospheric state, and the staff can enter the warehouse. operating. In addition, Apple should immediately organize the packaging, transportation and sales. The shelf life of generally preserved fruits is about 2 weeks. Apple into the storage of five Guan insisted good fruit into storage. Before the fruit is stored, the pests and fruits must be removed, and the bruised fruit should be removed to ensure that the robust fruit is stored to prevent rotting. Prepare to do a good job. For old cellars that have already been stored, they must be cleaned and disinfected prior to fruit storage in order to reduce the chance of germ transmission. They are usually fumigated with sulphur: 10 g sulfur per cubic meter or even spraying with 1% formalin solution. Then closed for two days, ventilation and then use, the ground can be sprinkled with a layer of lime disinfection. The freshly harvested fruit usually has a higher fruit temperature than the temperature. The fruit can be stored in a cool place overnight. The night temperature can be used to reduce the fruit temperature. When the fruit temperature approaches the cellar temperature, the fruit can be stored and the storage effect can be improved. After entering storage, it must be carefully managed. The suitable temperature for storing apples is -1 °C ~ 0 °C, so in the fruit before entering the storage and late storage should pay attention to cooling at night when the temperature is low. The appropriate humidity for storage of apples should be 85% to 90%. Higher humidity can reduce fruit moisture evaporation, reduce loss, and maintain a fresh and full state. The concentration of carbon dioxide should be controlled at 5% to 10%. In addition, reducing the concentration of oxygen in the cellar can make the apple crisp and color-preserving. Pay attention to prevent the occurrence of diseases during storage. The main diseases of apple during the storage period are tiger skin disease, anthrax, water heart disease, and penicillium. The specific prevention and control measures include: Strictly selecting the fruits and preventing the infected fruits from entering the pit; Before entering the storage, the conscientiously do a good job in the disinfection of the fruit pit; The fruit before the storage is sprayed with 50% thiophanate-methyl 1000 times or carbendazim 600 times. To kill the bacteria attached to the fruit. Timely sale. In the period before and after the Spring Festival, 80% of the stored fruit should be sold. Before and after the May 1st, the pit should be cleared, regardless of the selling price. The structure and type of the ventilation warehouse store ventilation. The ventilation warehouse should be constructed in a place with high dryness, low groundwater level and good ventilation. It is generally divided into three types: ground-based, semi-underground, and underground. The plane shape of the ventilation warehouse is mostly rectangular. The general warehouse is 9 to 12 meters wide, 30 to 40 meters long and 4 meters high. The direction of the warehouse is different due to the climatic conditions in different places. In the north, the construction of reservoirs tends to go from north to south in order to reduce the area of ​​the windward side of the winter and prevent the temperature of the reservoir from being too low. When building a warehouse, the most important thing is to choose a good wall, thermal insulation materials at the top of the warehouse. Under normal circumstances, the storage area with a capacity of less than 500 tons requires a ventilation area of ​​not less than 0.5 square meters per 50 tons of fruit. The arrangement of air intake facilities should generally be set at the base of the warehouse. Underground or semi-underground ventilation can also be used to introduce cold air into the central passage. The exhaust pipe is located in the center of the top of the warehouse, and it is more than 1 meter above the top of the warehouse. Usually every 5 to 6 meters, open a caliber 25 ~ 3525 ~ 35 cm exhaust. Storage management. Before the apple is stored, it is necessary to clean, ventilate, overhaul and sterilize the ventilation warehouse. Disinfection method is to use 10 grams of sulfur per cubic meter of storage capacity and sawdust, ignited after the smoke sealed for two days, and then open the ventilation. General disinfection after ventilation 2 to 3 days, the fruit can be stored. Ventilation storehouses store apples, either by stacking the boxes or by depositing the sand. However, the stacking of boxes can be used economically for storage and ventilation and management. After the fruit is put into storage, the management of the ventilation warehouse is mainly based on the differences in temperature and humidity inside and outside the warehouse, and the ventilation time and ventilation volume are correctly grasped to adjust the temperature and humidity inside the warehouse. Ventilation and ventilation are mostly performed when the temperature difference between inside and outside the reservoir is large. In the spring and autumn season, ventilation is usually more common at night when the temperature is low. When the temperature of the reservoir falls to a certain degree, the ventilation equipment is closed. During the winter season, the ventilation warehouse is dominated by insulation, and it is usually ventilated during the day when temperatures are high. In order to speed up the convection of air in the warehouse, exhaust fans and air extractors can be installed. When the air temperature is too high, ice can be placed at the air inlet, which can effectively reduce the temperature inside the warehouse. Cold storage storage Cold storage is also called mechanical refrigeration. This storage method is a warehouse built with good heat insulation materials and strong building materials, and is matched with mechanical refrigeration equipment. The temperature of the storage environment is controlled by mechanical refrigeration equipment. According to the requirements of the apple varieties on storage temperature, humidity and ventilation, the adjustment and control can be carried out. Therefore, it takes a long time for storage and preservation, and the effect is good. Variety selection and preparation before storage. Apples that can be kept fresh in cold storage can, in principle, be of any variety, but according to the varieties and economic goals of orchards, they should be stored in a variety of varieties that are difficult to keep fresh using simple storage methods, such as Red Star, Kim Shuai, Jonah King, etc., or storage prices. High, significant value-added after storage, better economic benefits, such as Red Fuji. Before warehousing, first sterilize the cold storage and all containers. The easiest way is to seal the cold store and disinfect it with sulfur. The specific approach is to use 1 to 2 kilograms of sulfur plus dry sawdust for every 100 cubic meters of storage capacity to ignite, seal it for 2 to 3 days, and remove the residual poison by unsealing, and then precool the cold storage. The light warehouse is usually pre-cooled for 3 to 5 days, and the heavy-duty civil construction (wall sandwich warehouse) is pre-cooled for more than 7 days, ie, the temperature in the warehouse can be stably reduced to about 0°C. Storage. Apples must be pre-cooled prior to storage, and they should be strictly controlled in batches and warehousing. After each batch of warehousing, it is necessary to cool down in time and wait for the next batch of warehousing to drop to the required temperature before entering the next batch. Generally, the daily storage amount should not exceed 1/10 of the total storage capacity. This is especially important for small cold storage. Apple preservation generally uses fresh-keeping packaging for storage. Over the years, more successful fresh-keeping packaging is the use of non-toxic polyvinyl chloride (PVC) special fresh-keeping bags. The general capacity of 10 to 20 kilograms, into the outer box storage storage. The stacking height of apples in the library varies depending on the situation. Apple's outer packaging is more sturdy and can withstand multi-layer pressure, it can be palletized directly, but the stacking height should not exceed 2.5 meters; if the outer packaging material is not very strong or stacking height exceeds 2.5 meters, consider stacking shelves and layering Palletizing. After racking, fresh-keeping apples can be placed directly on the shelves, eliminating the need for packaging. When palletizing, there must be a certain gap between the concrete wall and the concrete wall, between the concrete wall and the concrete box, and between the packing box to facilitate ventilation and cooling. Cold storage management. Cold storage management is mainly the inspection and adjustment of temperature, humidity and gas composition. After all the storage fruits are stored in the storage, the storage temperature should be reduced to about 0°C within 7 days and then maintained at minus 1°C to 2°C. Without the use of cold storage storage bags, the relative humidity within the library should reach 90%. When the relative humidity is low, a humidifier or a water sprayer should be installed in the warehouse; when using a cold storage room where the storage bag is stored, the humidity in the storage area should be reduced as much as possible. During the storage of fruits, CO2 and ethylene are released, and certain gases such as SO2 that are treated for preservation for a long period of time are also present in the library for a long period of time and should be excluded from the library in a timely manner. The fan is set inside the library, and the outside air is sent from the position in front of the evaporator fan to the inside of the reservoir, and fresh air can be replaced in time. However, a certain amount of air intake is required to reduce the temperature change in the refrigerator. Gas scrubbers can also be used, with water or spray brine to absorb CO2, SO2, and other gases. Trench storage location selection and setting. For the apple in the trench, the storage site should be located in a place with a flat terrain, a sunny leeward, a solid soil, a dry place without water accumulation, and convenient transportation and management. The size of the storage site can be determined according to the amount of stored fruit. Generally 250 to 300 kg of apples can be stored per square meter of trench. It is advisable that the ditch should be oriented in the north and south direction. The ditch depth is generally 0.8 to 1 m, and the ditch width is 1 to 1.2 m. The length of the ditch is determined by the topography and the amount of fruit. In the center of the bottom of the ditch, a groove with a depth of 20 cm and a width of 20 cm along the direction of the ditch is used to facilitate ventilation in the ditch. Around the ditch with soil to grow into a high about 30 centimeters of earthworms. In order to prevent cold wind and cold attacks, wind barriers should be buried around the storage area and 1 meter away from the ditch on the northern side of the ditch. A ridge-like bracket is erected above the ditch so as to cover the eaves and seats, prevent wind and cold, and resist wind and snow. The selection of fruit in the trench and pre-storage. Apples for the trench should be selected late-maturing varieties and appropriate late harvest, picking after picking, removing pests and fruits, fruits with mechanical injury and other fruits, and then pre-storage until the fruit cools down and then enter the trench storage . Apple pre-store more in the orchard on the spot. The method is to make a 20 cm deep and 1.2-1.5 m wide soil squat under the shade of cold and dry place, and build a sampan about 10 cm high. Start with the end of the pod and lay it layer by layer. Fruit thickness 5-6 layers. During the pre-storage period, it is shaded during the day and the cover is ventilated and cooled in the evening. Rainy weather prevents rain from entering the heap. Fruit storage and storage management. The pre-stored fruits are stored in time after the temperature is lowered. Before entering the ditch, lay a layer of 5 to 6 cm thick clean sand on the ditch, and then start from the end of the ditch and lay the fruit layer by layer. The fruit thickness is generally 60 to 70 cm. During the fruit setting process, a ventilation bar tied with straw or corn stalks is erected every 6 to 7 meters. Ventilation handles are about 10 cm in diameter and 10 to 15 cm taller than the top of the pile. After entering the ditch, cover the top of the heap with a layer of mat or 3 to 5 layers of cold-proof paper. Above the ditch, a ridge-like bracket should be erected, covered with a layer of corn stalks or mulch, shade and snow, and kept warm. During the entire storage period, it is necessary to do a good job of the management of the third period of junior high school according to the weather conditions. At the beginning of storage, it is the time for the fruit to enter the ditch for about one month. The focus of management during this period is to try to reduce the temperature of the storage environment. In the evening, cover the top of the gully and cover it with shade during the day. When the weather is dry and the humidity in the ditch is insufficient, water should be sprayed on the fruit pile to prevent the fruit from losing water and shrinking. In the middle of storage, it is the lowest temperature in the whole year, and the management focus of this period is thermal insulation and antifreeze. Gradually thicken the cover on the trench as the temperature decreases. Ventilators placed in the trenches should be tightly closed when the temperature drops to around 0°C. In the middle of the entire storage period, the ventilation of the cover is generally not released. The late period of storage refers to the early spring warming of the following year until the end of storage. The key to management, on the one hand, should be properly ventilated to prevent the temperature in the ditch from rising too fast; on the other hand, attention should be paid to changes in the weather to avoid freezing weather. At night, the cover on the ditch can be opened for ventilation, and cold temperatures at night can be used to reduce the temperature of the ditch. In March, when the weather gets warmer, the cover should be removed in several stages. Until about mid-March, except that only one layer of mat on the top of the shelf is protected from rain and sun, all other coverings can be removed and the fruit can be sold out as soon as necessary. China Agricultural Network Editor
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