Comprehensive storage and fresh-keeping packaging

Comprehensive storage and fresh-keeping packaging technology of famous green tea

1. Tea must be fully dried

the moisture content of tea has a great impact on the quality of stored tea. The moisture content of dry tea should be as low as possible, which is generally required to be less than 6%, but not less than 3%. This is the premise and foundation for extending the fresh-keeping and shelf-life of tea and applying other fresh-keeping technologies, and it is also an important measure to improve the flavor of famous green tea

2. A large number of research results at home and abroad show that among the existing tea preservation technologies, low-temperature refrigeration technology is the most advanced and has the best effect. The establishment of a special tea refrigerator is the most effective way to solve the storage and preservation of large quantities of famous green tea. Low temperature improves the efficiency of resource utilization. Cold storage can keep tea under low temperature, avoid light and dehumidification, and greatly extend the shelf life of tea. The only disadvantage is that the equipment investment is large and the use cost is high. However, now after summer, spring tea that has not been refrigerated and fresh-keeping has been neglected

the cold storage used for cold storage of tea is divided into combined cold storage and fixed cold storage in form. The combined cold storage has a relatively small volume, can be disassembled and assembled, flexible installation, good heat preservation, safety and convenience, but the price is relatively high. The city and small tea enterprises and retail departments store high-grade famous green tea for use. The self built cold storage has a relatively large volume and can only be used permanently, but the investment is relatively small, and there is a large choice of refrigeration equipment, which is suitable for large-scale storage of famous and high-quality green tea. The refrigerating capacity of the cold storage shall be determined according to the size of the warehouse and how much it is stored. Generally, it is controlled by an automatic temperature regulation system. The type refrigeration system and the cooling system work synchronously, and have the functions of automatic temperature regulation and dehumidification

considering the quality assurance effect and economic benefits of cold storage operation, it is appropriate to control the humidity of tea storage at 0 ~ 8 ℃ under the condition that the relative humidity is controlled below 65%

during the cold storage of famous and high-quality green tea, due to the large difference in humidity inside and outside the warehouse, when taking tea from the warehouse, the tea bag should be moved out of the warehouse first, and the opening of the bag can be opened only when the tea in the bag gradually heats up to close to room temperature. If the tea bag is opened immediately after leaving the warehouse, the water vapor in the air will liquefy into small drops of water when meeting the tea with low temperature, which will damp the tea and accelerate the aging of the tea

before tea storage, especially before the first use of the new cold storage, or the definition of using the tensile testing machine: test the mechanical and technological properties of materials, parts and components. When the relative humidity in the warehouse exceeds 65% in the material testing machine, the equipment and instruments should be changed in time to remove moisture. After long-term use of the cold storage, there will be peculiar smell in the storage, which is harmful to the quality of tea. It is necessary to change the air in time. Generally, the storage should be thoroughly cleaned once every 2-3 years to keep the storage clean and the air fresh

3. Fresh keeping technology of vacuum or air extraction and nitrogen filling packaging

both vacuum packaging and air extraction and nitrogen filling packaging require the use of aluminum foil or other composite membrane materials with more than two layers of gas (oxygen) resistance or iron and aluminum cans as packaging containers

vacuum packaging is to use a vacuum packaging machine to extract the air in the bag (can) and immediately seal it, so that the packaging container forms a relatively "vacuum" state, reduces the oxygen content, organizes the oxidation and deterioration of tea, and achieves the purpose of fresh preservation. Because the primary air extraction cannot reach a high vacuum degree, the oxygen concentration is still high. At present, a secondary vacuum packaging technology is invented, that is, first extract the air in the packaging bag, fill it with nitrogen, and form a "vacuum" state after the air extraction, which further reduces the oxygen concentration and has a better fresh-keeping effect. The vacuum packaging bag shrinks into hard blocks, which has a certain impact on the integrity of the appearance of famous green tea. In addition, the packaging is not flat and beautiful, so it is necessary to add appropriate outer packaging

the fresh-keeping of air extraction and nitrogen filling packaging is to first extract the air in the bag (can) to form a "vacuum" state, then fill it with nitrogen, and finally seal it tightly to keep the tea in a low oxygen environment, so as to achieve the purpose of fresh-keeping. The purity of nitrogen used should be high. In fact, due to impure nitrogen and high moisture content, the fresh-keeping effect is not as good as vacuum packaging

the one-time investment of vacuum packaging machine air extraction and nitrogen filling packaging equipment is large, especially the cans packaging equipment, which is suitable for large and medium-sized tea enterprises

4. Deoxidizing and fresh-keeping technology of deoxidizing agent

adopt a composite film container with good air tightness, add a small bag of deoxidizing agent into the tea, and then seal it. The oxygen concentration in the edible package is reduced to less than 0.1% within 24 hours, and the tea can be kept in an oxygen free state for a long time, so as to achieve the effect of fresh-keeping. It has the characteristics of obvious fresh-keeping effect, low cost, simple and practical method, and is suitable for all kinds of enterprises

modified atmosphere fresh-keeping technologies such as vacuum, air extraction and nitrogen filling or deaeration with deaerator are very suitable for the fresh-keeping of small packages of famous green tea in the circulation process. When used in combination with low-temperature cold storage fresh-keeping technology, the fresh-keeping effect will be better

as for the preservation of famous and high-quality green tea for household consumers, household refrigerators are now very popular. Using refrigerators to preserve tea at low temperature is a good method, which is not only simple and reliable, but also effective. The easiest way is to put a high-density polyethylene bag on the outer layer of the tea package. There are two kinds of wear measurement methods. Tie it tightly and put it in the freezer of the refrigerator (it can't be placed in the freezer. The English freezer has a bad smell and high humidity). When drinking, you should first take it out and put it at room temperature for a period of time, and then open the package when the tea temperature is close to room temperature

information source: China tea trade

this article is from the order of extruder enterprises, which will be greatly recovered. The copyright belongs to the original author, which is only for everyone to share and learn. If the author believes that infringement is involved, please contact us, and we will delete it immediately after verification