Storage and fresh-keeping of pear fruit

Different varieties and types of pear fruits require different standards of suitable temperature, humidity and the best gas composition. For the newly bred new varieties, the suitable temperature and humidity and the best gas composition required for storage must be found through experiments, so that the temperature and humidity and gas composition can be regulated effectively during storage, and the best storage effect can be achieved. The types of pear fruits can be roughly divided into two types.

1. Crispy meat type varieties: White pear system and sand pear system mostly belong to crispy meat type. After harvesting, most of the crispy meat varieties in Yin went through a gradual pre-cooling process at 10 ℃ and then stored at 0: 1 ℃. Take the new variety Jinfeng pear as an example: pre-cooling should be carried out before cold storage, the suitable pre-cooling temperature is 5-8 ℃, and the pre-cooling time is 2 days. Such as the use of natural low-temperature storage, in the night before the low-temperature pre-cooling night, the next morning into the warehouse early. The suitable storage temperature is 0: 1 ℃. After storage, the storage temperature should be lowered by all means. The temperature of cold storage should be reduced to 0 ℃ within 7-10 days, and the temperature of natural cold storage should be reduced to 0 ℃ within 30-40 days, the longest should not exceed 50 days. The storage temperature should not be lower than-1 ℃, otherwise chilling injury will occur and irregular brown spots will appear in the pulp. Generally, the relative humidity in the storage is kept at 85%-90%, and the relative humidity in the cold storage should be kept at 90%-95%. When the humidity in the storage is less than 80%, it is easy to shrink the pericarp. Water should be sprinkled on the ground when the humidity in the natural cold storage is insufficient (humidification devices can be added in the cold storage). Jinfeng pear is stored in controlled atmosphere under 0% ℃, oxygen should be kept at 10%-15%, carbon dioxide 1%-2%. Jinfeng pear is very sensitive to low oxygen and high carbon dioxide during long-term storage. Carbon dioxide poisoning will occur when carbon dioxide reaches more than 2% at a low temperature of 0 ℃. Oxygen can not be less than 10%, too low can also cause harm. Jinfeng pear is a storage-tolerant variety, which can be stored for 8 or 9 months at 0: 1 ℃ after harvest.

2. Soft meat type: this type includes Xiyang pear system and Qiuzi pear system varieties, which often become soft and lose storage value after harvest. Therefore, after pre-cooling after harvest, it should be stored at a temperature of about 0 ℃. Taking Nanguo pear as an example (including Hongnanguo pear and Dananguo pear), Nanguo pear belongs to soft-fleshy fruit with obvious respiratory transition period. When the respiratory peak comes, the fruit begins to age and the flesh begins to soften. Restraining and delaying the arrival of fruit respiration peak is an important technical measure to do well the storage of Nanguo pear. Nanguo pear was harvested in well-done, when the fruit respiration peak has not yet arrived, but the seed coat of the seed has become dark brown. The harvested Nanguo pears were pre-cooled at 5-7 ℃ for 2-3 days, and then stored in 0 ℃ cold storage for 3-4 months. After ripening, it can still maintain its original color, smell and smell.

If the Nanguo pear is stored in controlled atmosphere, it should be treated at 15 ℃ for 3-5 days, and then transferred to 0 ℃ controlled atmosphere storage. The oxygen concentration should be kept at 2%-3%, and the carbon dioxide concentration should be maintained at 3%-5%. After storage, the pear should be ripened for 5-6 months. The fresh-keeping effect of controlled atmosphere storage is better than that of ordinary cold storage. If simple controlled atmosphere storage is adopted, when the flesh of Nanguo pear has not yet softened or is becoming soft, it should be put into a PE bag 0.04mm thick and stored in a natural ventilation storage. the storage temperature should be about 15 ℃ at first, and gradually drop to 0 ℃ after 10 to 20 days. Stored in PE bag, the amount of fruit in the bag should not exceed 10 kg. The composition of the gas in the bag has changed. When the initial storage temperature is high, oxygen is 2%-3%, and carbon dioxide concentration is 5%-8%. When the storage temperature drops to 0 ℃, the oxygen in the bag rises to 5%-10%, and the carbon dioxide drops to 3%-5%. Pay attention to maintain a stable temperature, which can be stored for 3 to 4 months.