The controlled atmosphere cold storage for Tuoketuo Yellow River Wetland Management Committee is constructed for storing grapes. The cold storage temperature is designed at -1-0 ℃and the cold storage relative humidity is 90-95%. The entire cold storage is divided into 4 separate rooms, including three controlled atmosphere cold storages with the height of 5 meters and one ordinary cold storage. The total storage capacity is 300 tons. The project was completed in October 2014, and according to the after-sales tracking, cold storage equipment is operating normally.
Nature, picking and storage characteristics of grape
The freezing point of grape is at -3 ℃ or so, and the appropriate storage temperature is -1 ~ 0 ℃. Lower than the temperature of grape's freezing point, the berry tissue of the grape will be frozen and damaged. The appropriate humidity is 90 to 95%. Higher humidity causes fruit decay and lower humidity causes dehydration and degranulation of fruit stalk. Although grapes are non-respirable fruits, it is positive to grape preservation to raise carbon dioxide concentration by reducing the oxygen concentration in the environment. Generally the combination of 2 ~ 4% oxygen content and 3 ~ 5% of the carbon dioxide content is suitable for storage of most grape varieties. High-quality late-maturing varieties of grapes are more suitable for storage in controlled atmosphere cold storage, and generally they can be stored 2-7 months.
Grapes are prone to rot, fall from the grape stalk, its stalk is prone to dry. The decaying process can be slowed down by maintain the relative humidity in the controlled atmosphere cold storage. The problem of rot can be solved by eradication of fungi, for it is the fungi that result in rotting of grape, and Botryis Cinerea has strong resistance to low temperature.
Picking and pretreatment of grape
In the premise of not being frozen, grapes should be harvested when they are fully ripe. Fully mature grapes have high dry matter content, strong toughness, good coloring, fully formed fruit wax, enhanced storage resistance. It is proper to harvest grape when the weather is warm and clear, the temperature of the morning is low after the dew on the grapes is cleared or in the evening. Grapes are cut with scissors, and the injured grapes are removed. The grape clusters are laid flat in the 3-4 layer paper boxes or baskets. The containers should be shallow and small. When the grape clusters are filled with the container, they are covered with paper to prevent cold.