Packaging, storage and fresh-keeping technology of

Packaging, storage and fresh-keeping technology of mountain peach

1 Storage characteristics

peaches are not resistant to storage

2. Harvesting period

storage at room temperature or long-distance transportation requires a slightly lower maturity, which is generally sevenoreight mature; When refrigerated at low temperature or sold fresh on the spot, the maturity should be 89. When harvesting, you should choose sunny days and the morning and evening after dew evaporation, hold the peaches with your hands, twist them, and handle them gently to avoid mechanical damage

3. Pre cooling treatment

(1) 0.2 torque measuring precision is used for water cooling: 1% of cold water at 5 ℃ -1 ℃ is used for pre cooling. This cooling method is fast, and it can meet the requirements in 2 hours, and can prevent water loss. However, it needs to be dried after cooling before packaging

(2) air cooling takes 7-8 hours, and the speed is slow, which is easy to cause the peach to lose water and wilt, reducing the quality, but avoiding the decay in storage and transportation caused by incomplete drying after water cooling. Sometimes, water and air mixed precooling can also be used to give full play to the advantages of these two methods to achieve the ideal precooling effect

4. Packing method

put the selected peaches without pests, mechanical damage, hail damage, consistent maturity and uniform size into corrugated boxes, wooden boxes or plastic baskets, lined with plastic pallets. If the peaches are stored and transported in bamboo baskets, they need to be packed with soft paper single fruit, and paperboard is sandwiched in the middle of each layer, so as to better avoid friction and crush injury. You can also wrap single fruit in paper and put it into a container lined with polyethylene plastic film bags. The packaging container should be shallow and small. Generally, it is appropriate to hold 5 kg-10 kg peaches

5. Storage method

(1) the suitable cold storage temperature for cold storage and fresh-keeping method is -0.5 ℃ -0 ℃, and the relative humidity is 90%. If you want to store for a long time, you must strictly control the temperature of the cold storage. The temperature of the cold storage cannot fluctuate, and there will be the possibility of freezing below -1 ℃. At the initial stage of storage, peaches can be properly ventilated. Under low temperature conditions, chilling injury symptoms will appear after 2 weeks. When it is moved to high temperature environment for post ripening, the pulp will become dry, spongy and soft, and the pulp around the core will obviously turn brown. In serious cases, patterns can be seen on the outer skin, and the skin color is dim and lusterless, and the flavor will change. Peaches stored at 2 ℃ -5 ℃ are more prone to pulp deterioration than those stored below 0 ℃. The varieties with better storage resistance can be stored for 4 weeks under the stable condition of -0.5 ℃ -0 ℃, and the quality is good. If peaches are refrigerated for too long, they will be insipid. Therefore, their storage period should not be too long

(2) modified atmosphere storage and fresh-keeping methods peaches are stored at a temperature of 0 ℃, a relative humidity of 85%-90%, and a volume fraction of carbon dioxide of 5%6 The maximum stroke of the movable beam (mm): 800. It can be stored for 6 weeks in the controlled atmosphere environment with the volume fraction of oxygen below 1%, which is twice as long as the storage period of peaches refrigerated in the air. If bricks or zeolites soaked in potassium permanganate are added to the modified atmosphere bag to absorb ethylene, the effect will be better. It is reported that in terms of production technology, spontaneous controlled atmosphere storage using fresh-keeping bags and CT series of controlled atmosphere preservatives can be stored for 2 months at 0 ℃ -2 ℃ and at least 8-10 days at 25 ℃ -30 ℃

(3) chemical storage and fresh-keeping methods peach household materials have four obvious characteristics. During storage, a large number of peaches often rot due to brown rot. Before the storage of peaches, if the suspension of Benadryl with a mass fraction of 0.1% is soaked at 40 ℃ for 25 minutes, the decay of peaches can be prevented

(4) ice cellar storage and fresh-keeping methods when there is no mechanical cold storage in northern China, ice cellars can be used to store winter peach and other more storage resistant varieties. In areas where there is no natural ice source, artificial ice can be made in the cold season. The specific method is to chisel the ice into large ice blocks 30 cm-40 cm thick, about 1 m long and 1 m wide respectively, and put them in the cellar, and lay straw 40 cm-50 cm thick at the bottom of the cellar to prevent ponding after icing, and then seal the cellar door for ice storage. When the peaches are ripe, remove the ice in the cellar, stack a layer of 40 cm thick ice at the bottom and around the cellar, stack the peaches packed in boxes or baskets on the ice, and fill the packaging with crushed ice. After each layer is stacked, put a layer of ice on it. After stacking, cover the top layer with thermal insulation materials such as sawdust or rice straw with a thickness of about 1 m. The cellar door must be sealed tightly. When the cellar must be opened for inspection, the working time should be shortened as far as possible. The cellar temperature should be kept at 0 ℃ -1 ℃. Once the ice melting temperature rises, the peaches should be taken out of the cellar immediately

(5) storage and fresh keeping in the refrigerator. After the pre cooled peaches are dried, they are packed in plastic bags and stored in the refrigerator. The temperature is controlled at 0 ℃, the relative humidity is controlled at 85%-90%, and the storage period can reach 1 month

6. Storage points

peaches are soft and juicy, with thin skin and tender meat when mature, and are not resistant to storage. Comprehensive measures need to be taken for storage and preservation after picking

(1) formulate different storage measures according to different varieties. Generally, late maturing varieties such as snow peach and winter peach are more resistant to storage, followed by medium maturing varieties such as Okubo and Baifeng, and early maturing varieties such as honey peach and may fresh are the least resistant to storage

(2) pre cool the peaches as much as possible after harvest. After harvest, pre cool the peaches to the required temperature as much as possible, and then adjust the air humidity by watering, hanging wet straw curtains, etc., and control it to about 90% as much as possible

(3) reducing the occurrence of chilling injury requires that when storing for a long time, attention should be paid to the control of temperature to reduce the occurrence of chilling injury

(4) post ripening treatment peaches that need to be stored and preserved quickly need to be taken out of the warehouse and transferred to a room with higher temperature for post ripening before sale or processing. The length of time required for peach ripening depends on the temperature, which is generally 18 ℃ -29 ℃, and should not be too high or too low. When the temperature is 20 ℃ -25 ℃, it takes 3-4 days to finish ripening; It takes about 8-10 days at 16 ℃; At 10 ℃, it takes 15-20 days. The ripening of peaches requires speed. The faster the ripening, the better the quality of peaches

source: printed in Guangzhou