1. Preservation and freshness preservation means keeping fresh, including preservation, transportation, and sales, etc. The usual meaning of preservation refers to the storage and preservation of vegetables after fruits. 2. The internal nature of preservation and the inherent quality of external fruits and vegetables are the inherent nature of its freshness. This inherent nature of the variety is internal. Taking various measures to suppress aging, keeping fresh measures is an external factor. The quality of fruits and vegetables and the absence of injuries are the basis for good preservation. Storage technology is an external cause and can only supplement and modify certain biological characteristics of fresh-keeping products. For a given product, no matter what kind of advanced preservation technology is adopted, its storage life is limited, only pre-harvest production and cultivation Post-harvest preservation techniques complement each other to achieve optimal storage. 3, the chemical composition of fruits and vegetables and its changes in post-harvest ripening The chemical composition contained in fruits and vegetables can be divided into two parts, namely water and solids. (1) Moisture: Most fruits and vegetables account for more than 80% to 90% of water content. Moisture is an important component that affects the tenderness, freshness and taste of fruits and vegetables, and is closely related to the flavor quality of fruits and vegetables. After the fruits and vegetables are harvested, the water is not supplemented, and it is easy to evaporate and lose moisture during transportation and cause wilting, weight loss, and loss of freshness. The degree of water loss is closely related to the types and varieties of fruits and vegetables, and the conditions of storage and transportation. (2) Inorganic components: mineral elements such as: potassium, sodium, calcium, magnesium, phosphorus, sulfur, trace elements such as manganese, zinc, molybdenum, boron, etc. (3) Vitamins: such as vitamin B1, vitamin B2, vitamin C, vitamin A, vitamin E, and vitamin K. (4) carbohydrate: such as sugar, starch, cellulose, pectin substances. Sugar and starch can be transformed into each other, such as green peas stored at high temperatures, after two days of sugar synthesis of starch, so that sugar is reduced, reduced sweetness, quality deterioration. (5) Organic acids: such as citric acid, malic acid, oxalic acid, etc. (6) Pigment substances: such as chlorophyll, carotenoids (including: carotenoids, lycopene, lutein, paprika, and lycopene), anthocyanins. (7) Tannin Substances: Polyphenolic compounds have astringent astringency. Browning is caused by the oxidation of single condensate under the action of enzymes. Pre-harvest calcium spray on grapes inhibits post-harvest polyphenol oxidase activity and reduces tannin oxidation and browning. (8) Aromatic substances: Alcohols, esters, aldehydes, ketones, etc., and waxes. The formation of waxes enhances the protection of the skin of fruits and vegetables, and reduces the transpiration of water and the invasion of germs. Therefore, do not wipe the fruit powder when harvesting, so as not to affect the storage stability of fruits and vegetables. (9) Nitrogen compounds: mainly proteins, amino acids, etc. (10) Glycosides: Glycosides are compounds in which a glycosyl group and a non-glycosyl group are combined and can be hydrolyzed to produce sugar and aglycone under the action of an enzyme or an acid. (11) Enzymes: such as oxidoreductases, pectinases, cellulases, amylases, and phosphorylases. Artificial Insemination Syringe Artificial insemination Syringe AI GUN Jinan Mucho Commercial Inc. , https://www.muchovet.com