Vacuum precooling fresh-keeping technology of flowers and storage methods of flower seeds

Vacuum pre-cooling fresh-keeping of flowers after harvest. The harvested flowers should be cooled rapidly, that is, pre-cooling. There are many methods of precooling preservation of flowers, one of which is vacuum precooling. Vacuum precooling fresh-keeping is based on the characteristic that vacuum precooling can accelerate water evaporation, flowers are placed in vacuum precooling tank for vacuum treatment, part of the water in flowers transpirates outward, and the latent heat is released in vitro with water vapor. so that the flowers can cool down quickly. Vacuum precooling not only has high speed and uniform cooling, but also reduces the oxygen concentration and ethylene release concentration of flower tissue due to the decrease of air pressure, which can effectively maintain the freshness of flowers and prolong the storage life.

Technological parameters of vacuum precooling fresh-keeping of flowers. The vacuum precooling preservation of flowers is mainly to control the temperature and humidity by controlling the vacuum degree of the precooling process. The required vacuum is related to the physiological characteristics, sensitivity, humidity of flowers and the performance of vacuum equipment in the precooling tank.

Problems and countermeasures in vacuum precooling preservation of flowers. The process of vacuum precooling fresh-keeping of flowers will cause water loss of flowers, about 1% of water loss for every 10 ℃ of temperature drop, such as temperature from 30 ℃ to 5 ℃, about 3% of water loss. If the loss of the level of flowers is serious and the surface stomata are open, it will lead to the decrease of freshness and affect the quality of flowers. Therefore, flowers must be strictly controlled to have appropriate humidity. A kind of spray vacuum precooling equipment has been applied in the United States, which can not only effectively avoid dehydration in the process of flower precooling, but also quickly cool down. At present, the author is in vacuum precooling treatment. Water absorption means that flowers absorb water for a period of time before precooling, and then put together with the container in a vacuum tank for vacuum precooling. This method is mainly suitable for flowers that require lower final temperature of precooling (such as 1 ℃ to 2 ℃). In addition, for flowers with more buds after harvest, about 1% silver nitrate is added to the container water as a preservative. The water absorption treatment affects the production efficiency because the container occupies a certain space of the vacuum tank. Water spray treatment refers to the use of humidifier to evenly spray and heat flowers before pre-cooling, so that flowers can be evenly sprayed and humidified before pre-cooling, so that chemical plants have enough moisture before pre-cooling. The practice shows that the water spraying treatment is simple and applicable.

Vacuum precooling has the remarkable characteristics of fast cooling time (usually only 20 to 30 minutes), high efficiency, uniform cooling, not affected by packaging and so on. It is especially suitable for pre-cooling and fresh-keeping of articles with large surface area and volume ratio such as flowers. The vacuum precooling preservation of flowers remains to be explored and experimented. With the continuous improvement of the precooling process and the further improvement of the performance of vacuum precooling equipment, the application of vacuum precooling preservation in flower storage or transportation will become more and more popular.