New technology of mechanical cold storage for the

The supply time of watermelon can be adjusted through cultivation methods (such as early spring, late autumn, protected cultivation) and transportation in the South and North. At present, the mechanical cold storage technology of watermelon is also an effective method to solve the market supply

we use a high-frequency fatigue testing machine in a postmodern small cold storage equipped with corresponding experimental fixtures. In a well insulated building warehouse, we are equipped with mechanical cooling equipment. According to the storage characteristics of watermelon, we artificially adjust and control the temperature, humidity and gas components in the storage environment to prolong the fresh-keeping period of melon. For example, Fengshou No. 1, disease resistant black giant and other middle and late maturing varieties can be stored for D, with good commodity performance and considerable benefits. The specific operating procedures can also test the S-N curve. As follows, the mechanical property test items of plastics are relatively simple. 1:

1. Variety selection

the tissue structure and chemical composition of watermelon are different in different varieties. The tissue structure and chemical components of the same watermelon variety were significantly changed due to the influence of growth environment factors. For the watermelon used for storage and preservation, the middle and late maturing varieties should be selected, which have high sugar content, good flavor, bright color, and no diseases and pests on the vine and fruit surface

II. Recovery requirements

1. Maturity selection. The maturity of watermelon is closely related to variety, sowing date and accumulated temperature after fruit setting. The maturity period of the same variety is different every year. To determine the harvest maturity, it is best to select a non-destructive melon and fruit tester. Align the probe center line of the tester with the center point of the fruit. A melon less than 8 degrees is a raw melon, and a melon greater than 8 degrees is a mature melon. For watermelon used in cold storage, 8 mature melons should be selected. The fully mature watermelon tissue is easy to be damaged, affecting the storage quality, resulting in the hollow pulp of the fruit, which is soft and tasteless when eaten, and even rotten

2. 80% and (9) 0% of the results are still to be collected in the laboratory; The scope of the enterprise is small, and the R & D funds are lack of methods. Harvesting in the evening is beneficial to reduce the product temperature. When picking, leave 5cm branches and vines on the upper end of the melon stalk to reduce water evaporation and wound infection

III. precooling

precooling refers to cooling the watermelon to the specified temperature range as soon as possible before entering the cold storage, so as to better maintain its original quality. The simplest method of precooling is to stack them in the field after picking, use low temperature precooling at night, and store them in the warehouse before the temperature rises in the morning. Within one week after warehousing, the refrigerator is used to circulate cold air to cool the watermelon with the help of heat conduction and evaporation latent heat, so that the temperature of the watermelon is consistent with that of the cold storage. The general temperature is ℃, the relative humidity is about 80%, and the minimum storage temperature can be controlled at ℃

IV. disinfection and refrigeration of cold storage

watermelon cold storage and utensils shall be disinfected with 0.1mg/kg carbendazim spray d before use to keep the warehouse clean and free of miscellaneous bacteria. Start the refrigeration system in the warehouse, regulate the storage temperature to ℃, and then reduce it to the optimal temperature within one week according to the characteristics of watermelon varieties

v. management of cold storage

1. Temperature of cold storage. The suitable temperature for cold storage of watermelon is ℃, especially in the early stage of storage, it should be gradually cooled down and then transferred to normal storage, so as to reduce the physiological diseases of watermelon and improve the storage quality. When watermelon is taken out from the cold storage in summer or autumn, it is easy to condense water droplets on the surface of the melon, and the shelf life after delivery is very short. Therefore, it is necessary to gradually heat up before delivery, so that the watermelon temperature can be gradually raised to the appropriate temperature before delivery, which is conducive to ensuring the quality and extending the shelf life

2. Humidity of cold storage. The appropriate relative humidity for watermelon cold storage is%, because the evaporation pipe often forms frost, and the frost is washed away, and the buildings use cement materials, the humidity in the warehouse is reduced. If the humidity requirements of watermelon are not met, clean water can be sprinkled on the ground or grass curtains can be paved

3. Ventilation of cold storage. Watermelon in the cold storage emits CO2, ethylene and other irritant gases through respiration. When the concentration reaches a certain level, it will promote the ripening and senescence of watermelon fruit, and the quality will deteriorate, so it can not be stored for a long time. Therefore, ventilation is necessary. In the morning when the temperature is low, open the exhaust window. While ventilation, open the automatic spray to send the fine water mist into the warehouse with the cold wind. The effect is more ideal

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