1. Technical requirements for tea packaging Tea contains ascorbic acid, tea tannin, tea, aromatic oil, protein, catechin, lipids, vitamins, pigments, pectin, enzymes and minerals. These ingredients are highly susceptible to deterioration due to moisture, oxygen, temperature, light and environmental odors. Therefore, when packaging tea leaves, the influence of the above factors should be weakened or prevented, and the specific requirements are as follows.

1.1 Moisture resistance The moisture in tea is the medium for the biochemical change of tea. The low moisture content is conducive to the preservation of tea quality. The water content in tea should not exceed 5%, and 3% is best when stored for a long time. Otherwise, ascorbic acid in tea will be easily decomposed, and the color, aroma and taste of tea will change, especially at higher temperatures. The speed will increase. Therefore, it is possible to use a composite film such as an aluminum foil or an aluminum foil vapor-deposited film as a base material for moisture-proof packaging during packaging.

1.2 Anti-oxidation Excessive oxygen content in the package will lead to oxidative deterioration of certain components in the tea. For example, ascorbic acid is easily oxidized to become deoxyascorbic acid, and further reacts with amino acids to cause a pigment reaction, which deteriorates the taste of the tea. Therefore, the oxygen content in the tea packaging must be effectively controlled below 1%. In packaging technology, aeration packaging or vacuum packaging can be used to reduce the presence of oxygen. The vacuum packaging technology is to put the tea into a soft and flexible film packaging bag, to exclude the air in the bag during packaging, to cause a certain degree of vacuum, and then to seal the sealing method; the air-filling technology is to discharge the air At the same time, it is filled with an inert gas such as nitrogen, in order to protect the color, fragrance and taste of the tea leaves from being stable and maintain their original quality.

1.3 Anti-high temperature Temperature is an important factor affecting the quality of tea. The temperature difference is 10 °C, and the rate of chemical reaction is 3 to 5 times. Tea leaves will exacerbate the oxidation of the contained substances at high temperatures, resulting in the rapid reduction of effective substances such as polyphenols and the deterioration of quality. According to the implementation, the storage temperature of the tea leaves is preferably 5 ° C or less. At 10 to 15 ° C, the color of the tea leaves is slower, and the color effect can be maintained. When the temperature exceeds 25 ° C, the color of the tea leaves will change rapidly. Therefore, the tea leaves are suitable for storage at low temperatures.

1.4 Shading light can promote the oxidation of chlorophyll and lipids in tea, increase the odorous substances such as valeraldehyde and propionaldehyde in tea, and accelerate the aging of tea. Therefore, when packaging tea leaves, it must be shielded from light to prevent chlorophyll and fat. Photocatalytic reactions occur in other components such as the substance. In addition, ultraviolet light is also an important factor causing deterioration of tea. Shading packaging technology can be used to solve such problems.

1.5 Gas barrier The fragrance of tea is easily lost, and it is easily affected by external odor. In particular, the residual solvent of the composite membrane and the odor of the electric iron treatment and heat sealing treatment will affect the flavor of the tea and affect the fragrance of the tea. Therefore, when packaging tea leaves, it is necessary to avoid escaping from the package and absorbing odor from the outside. Tea packaging materials must have certain barrier properties.

2. Packaging method of tea As a special kind of commodity, the packaging of tea is different from the packaging of other general commodities due to its own and objective conditions. At present, the commonly used tea packaging methods mainly include the following.

2.1 Metal can packaging The metal can packaging is excellent in anti-breakage, moisture-proof and sealing performance, and is an ideal packaging for tea. Metal cans are generally made of tin-plated steel sheets, which are square and cylindrical, and are covered with a single layer cover and a double layer cover. There are two types of general tanks and sealed tanks. In the packaging technology processing, the general tank can be enclosed in a deoxidizer packaging method to remove oxygen in the package. Sealed tanks are mostly inflated and vacuum packed. The metal can is superior to the composite film in the protection of the tea, and the appearance is beautiful and noble. The disadvantage is that the packaging cost is high, the weight ratio of the package to the commodity is high, and the transportation cost is increased. The exquisitely designed metal cans are suitable for the packaging of high-grade tea.

2.2 Carton packaging The carton is formed by printing on white paper, gray board paper, etc. The carton packaging is easy to break and the shading performance is excellent. In order to solve the volatilization of the tea leaves in the carton packaging and to avoid the external odor, the tea leaves are generally packed in polyethylene plastic bags and then loaded into the carton. The disadvantage of carton packaging is that it is susceptible to moisture. In recent years, paper-plastic composite packaging boxes have emerged to overcome the problem of moisture-absorbing carton. This kind of paperboard made of plastic film layer or moisture-proof coating is made of packaging material. The packaging box not only has the function of packaging the composite film bag, but also has the protection and rigidity of the carton packaging. If a plastic bag is used as a small bag inside, the protective effect is better.

2.3 Plastic molding container packaging Plastic molding containers such as polyethylene, polypropylene, polyvinyl chloride, etc. have the characteristics of generous, beautiful, and good packaging display effect, but their sealing performance is poor. They are mostly used as outer packaging in tea packaging, and their packaging Multi-purpose composite film plastic bag packaging.

2.4 Composite film bag packaging Plastic composite film has many advantages such as light weight, not easy to break, good heat sealability and reasonable price, and is widely used in packaging. There are many kinds of composite films for tea packaging, such as moisture-proof cellophane/polyethylene/paper/aluminum foil/polyethylene, biaxially oriented polypropylene/aluminum foil/polyethylene, polyethylene/polyvinylidene chloride/polyethylene, etc. The composite film has excellent gas barrier properties, moisture resistance, aroma retention, odor prevention and the like. Since most plastic films have a light transmittance of 80% to 90%, in order to reduce the transmittance, ultraviolet light suppression can be added to the packaging material or the light transmittance can be reduced by printing or coloring. In addition, a composite material based on an aluminum foil or a vacuum aluminized film may be used for the light-shielding packaging. The composite film bag is packaged in a variety of forms, including a three-sided sealing shape, a self-standing bag shape, a folding shape, and the like. Because the composite film bag has good printability, it is used for sales packaging design, which has a unique effect on attracting customers and promoting tea sales.

2.5 Paper Bag Packaging Also known as teabag, this is a kind of bag packaging made of thin filter paper for the village. When it is used, it is placed in the tea set together with the paper bag. The purpose of packaging in a filter paper bag is mainly to increase the leaching rate, and also to make full use of the tea plant tea. Because the tea bag has the advantages of fast brewing, clean and hygienic, standard dosage, convenient mixing, convenient slag discharge, easy to carry, etc., it can adapt to the fast-paced life needs of modern people and is very popular in the international market. Early bagged teas generally have bag lines to meet the convenience of multiple soaking. Due to environmental protection requirements, bagged tea without bag lines is now becoming popular.