Vegetables and fruits are fresh foods, which are perishable after harvesting. In order to extend the preservation period, researchers from various countries have invented a variety of fresh-keeping techniques. First, the preservation of carton This is a new type of carton developed by the Japan Food Circulation System Association in recent years. Researchers used a "Ristoval" (a type of silicate) as an additive to pulp. Due to this kind of stone powder, it has unique adsorption effect on various gases, and it is cheap and does not require low-temperature and high-cost equipment. It has a long-term preservation effect, and the weight of fresh fruits and vegetables will not be reduced, so businesses love it. With it, it is even more unique to carry out long-distance storage and transportation. Second, the microwave preservation This is a Dutch company for the preservation of fruits, vegetables and fish-meat foods at low temperatures. It uses microwaves to heat it up to 72Â°C in a short time (120s), and then this processed food is listed at 0ï½ž4Â°C and can be stored for 42-45 days without deterioration. Suitable for the off-season supply of "seasonal fruit", much favored by people. Third, edible fruits and vegetables preservatives This is a British food association developed by the edible preservatives. It is a "translucent emulsion" formulated with sucrose, starch, fatty acids and polyesters. It can be sprayed, brushed, and impregnated into watermelons, tomatoes, bell peppers, eggplants, cucumbers, apples, Bananas and other surfaces can be stored for up to 200 days. This is because this preservative forms a layer of â€œsealing filmâ€ on the surface of fruits and vegetables, which completely prevents oxygen from entering the interior of fruits and vegetables, so as to achieve the purpose of prolonging the ripening process of fruits and vegetables and enhancing the preservation effect. Fourth, the new film preservation This is a one-time consumption of moisture absorption and preservation of plastic packaging film developed in Japan, which is composed of two translucent nylon membrane with strong permeability, and between the membrane with natural Sugar syrup with high osmotic pressure and osmotic pressure can slowly absorb moisture leaching from the surface of vegetables, fruits and meat to achieve freshness preservation. Fifth, the pressure preservation This is successfully developed by the Institute of Food Science, Kyoto University, Japan, the use of pressure to produce food methods, vegetables after pressure sterilization can extend the preservation time, improve the fresh taste, but the acid can not play a role in the pressurized state, Therefore, it is best to keep pickles and fruits under the best conditions. Six, ceramic storage bag This is a Japanese and a company developed a far infrared fruit and vegetable fresh-keeping bag, mainly in the inner side of the bag coated with a thin layer of ceramic material, so through the ceramic can be released by the infrared and The water contained in fruits and vegetables undergoes a strong "resonance" movement, which promotes preservation of fruits and vegetables. VII. Microbial Preservation Method Ethylene has the effect of promoting the aging and maturation of fruits and vegetables. Therefore, if fruits and vegetables are to be preserved, the ethylene must be removed. After screening research, the scientists isolated an "NH-10 strain" that can be used to make ethylene-removing "NH-T" substances that prevent browning, loosening, and grain loss during storage. Tomato, pepper to prevent loss of water, discoloration and loose effect, there is a clear effect of preservation. Eight, decompression and preservation method It is a new method of storage of fruits and vegetables, has a good effect of preservation, and has the advantages of convenient management, simple operation, low cost, etc. At present, Britain, the United States, Germany, France and other countries have developed The low-pressure containers with standard specifications have been widely used in long-distance transportation of fruits and vegetables. IX. Preservation of hydrocarbon mixtures This is a â€œnatural edible preservativeâ€ that can be used to extend the storage life of tomatoes, peppers, pears, grapes, and other fruits and vegetables by a British company, Sembep Biotechnology. It uses a complex mixture of hydrocarbons. When in use, it is dissolved in water to be in a solution state, and then the fruits and vegetables to be preserved are soaked in the solution so that the surface of the fruits and vegetables is uniformly coated with a liquid agent. This greatly reduces the amount of oxygen absorbed and causes almost all of the CO2 produced by the fruits and vegetables to be discharged. Therefore, the effect of preservatives is exactly like giving â€œanestheticsâ€ to fruits and vegetables to make them sleep. Ten, electronic technology preservation method It is the use of negative oxygen ions and ozone generated by high-voltage negative electrostatic site to achieve the purpose. Negative oxygen ions can passivate the enzymes that cause metabolism of fruits and vegetables, thereby reducing the respiratory intensity of fruits and vegetables, and reducing the production of ethylene as a fruit ripening agent. Ozone is a strong oxidant, and it is also a good disinfectant and fungicide. It can not only eliminate microorganisms on fruits and vegetables and secrete toxins, but also can inhibit and delay the hydrolysis of organic matter in fruits and vegetables, thereby prolonging the storage period of fruits and vegetables.