Tea packaging material selection to consider quality and safety

Tea is a food for people to drink. It is a kind of product that needs to use packaging to prevent pollution and reduce deterioration due to environmental changes. Therefore, in the tea packaging, the effectiveness of the packaging should be considered first, that is, to maintain the health and quality of the product.

First, tea packaging materials

At present, there are many materials suitable for tea packaging, including paper, plastic film, metal and ceramic, and a small number of bamboo, wood and other materials. Tea packaging materials, like other packaging materials, have seen rapid development and design research. In particular, various composite packaging materials are used in tea products, such as paper-plastic composites, plastic-plastic composites, and aluminum-plastic composites. From the form of packaging, there are mainly three kinds of bags, boxes and cans.

The general requirements of tea packaging materials are: First, economic and health, not only cheap, but also in line with national health requirements; Second, durability, preservation, first of all moisture, but also consider to prevent the entry of various gases and microorganisms.

Second, the principle of tea aging

The quality of tea is mainly composed of tea polyphenols, amino acids, alkaloids, vitamins, chlorophyll and other aroma components. These quality components are mostly reducing substances, and are easily affected by environmental factors such as humidity, temperature, light, and oxygen, and undergo hydrolysis reaction, oxidation reaction, condensation, or polymerization reaction with themselves or each other. As a result, some of the larger molecules are formed, resulting in precipitation of tea broth or reduction of water leaching and producing some odors called "Chen". This is the main mechanism for aging of tea leaves.

1. Oxidation and polymerization of tea polyphenols

Tea polyphenols are the general name for more than twenty kinds of phenolic substances contained in tea, and they are the most important components that determine the color and taste of tea. Tea polyphenols are colorless, but they are prone to change. Enzymatic reactions, oxidation reactions, and condensation (polymerization) reactions produce what we call theaflavins. Theaflavins are further oxidized and condensed (polymerized) to produce tea red. In addition, the oxidation and condensation (polymerization) of thearubigins further produce theaflavins. Black tea is produced in the hope of obtaining a higher proportion of theaflavins and thearubigins, while minimizing the production of theaflavins (tea browning will make the taste worse). Green tea is characterized by high tea polyphenols retention. Therefore, the storage of tea leaves is to prevent the further oxidation of tea polyphenols, which makes tea soup brown and taste worse.

2. Changes in amino acids and alkaloids

Amino acids and caffeine are the main substances that impart fresh and pleasant taste to tea soup. There are many kinds of amino acids in tea, mainly theanine, with relatively high content. More than 90% of alkaloids are caffeine. They are all nitrogenous substances. In the process of tea storage, it is easy to combine with the oxidizing substances of tea polyphenols to produce a dark-colored polymer, so that the tea loses its original taste.

3. Changes in chlorophyll and vitamin C

Chlorophyll is an important ingredient in the formation of the color of green tea. Vitamin C is a health-care ingredient contained in green tea. However, they are extremely vulnerable to environmental damage. Chlorophyll is easily decomposed under the action of light or heat, causing browning of tea leaves. Vitamin C is also a substance that is easily oxidized. It is oxidized under the action of light or heat, and then reacts with other substances to make the quality of green tea significantly lower.

4. Changes in tea aroma components

The aroma components of tea are more complicated and the contents of the ingredients are less. Mainly some alcohols, aldehydes, lipid compounds, as well as some reduced sulfides. With the prolongation of the tea storage time, various aroma components have been oxidized or transformed, making the fragrance of the new tea declining, and the taste of the tea has revealed.

Third, the quality control of tea packaging

The quality of tea is subject to changes in the environment. There are many environmental factors, mainly:

1. The moisture resistance of moisture-proof tea packaging is very important. Tea should be strictly controlled before packaging (within 7% or less), good moisture resistance of the packaging material delays various hydrolysis reactions in the tea, and the tea quality can be well maintained.

2. It is important to avoid darkness in dark tea packaging. Illumination will speed up the condensation reaction and changes of various components of tea, especially the destruction of chlorophyll and other substances, and reduce the quality of tea. The good light protection performance of the packaging material keeps the quality of the tea better.

3. Environmental Oxygen Gas barrier properties of tea packaging are also important. Oxygen in the atmosphere will accelerate the oxidation reaction of various quality components in tea to reduce the quality of tea. Good gas barrier properties of packaging materials can also maintain the quality of tea.

4. Security of packaging materials There are many companies that currently produce tea packaging materials, but the health status of these companies is worthy of attention. Many countries in the world have already required companies that produce food packaging materials to be treated as equivalent to producing food companies. China has no provisions in this regard. In addition, many domestic companies that produce composite packaging materials misuse printing inks, thinners, adhesives, etc. in the production process, resulting in many packaging materials with many strong odors. Packaging tea leaves with these packaging materials will allow the tea to absorb these odors and destroy the original aroma and taste of the tea leaves. It should cause great concern to tea producers and consumers.

At present, there are two unfavorable tendencies for tea products sold on the domestic market: On the one hand, the proportion of loose tea sales is increasing. Not only tea houses, large shopping malls sell loose tea, and even large-scale warehouse-type supermarkets sell counters. Tea, not only does not help maintain and improve the quality of tea, but also adds difficulty to quality supervision and management. The sale of tea loose tea not only does not guarantee the hygiene and quality of the product, but also makes the product lack the required quality and specifications. The sales of loose tea were welcomed by the market. First, consumers were not assured of the quality of the interior of the packaged tea. They were mistakenly thinking that the loose tea was directly listed on the production site, and they could be seen and randomly selected and sometimes countervailed. Satisfy the consumer psychology. In fact, many loose teas are sold through the middle of many counters. Many teahouses and counter operators do not purchase directly from the origin, but they are randomly purchased from the tea wholesale market or tea dealers. To guarantee, and shoddy and counterfeit phenomenon is very serious. Second, operators use most of the consumers who do not understand the quality of tea. They mistakenly think that the tea with beautiful appearance and good name has a high price, and they can do their best. At the same time, they can avoid quality supervision and management, and it is difficult to determine the origin and production enterprises. A large number of scattered tea sales in the market not only cause the production companies to lose the basis of quality, credibility, and brand, but also create a lot of market opportunities for scattered and brave sellers. The sales of loose tea also caused confusion in the product name and price. The names of tea products are getting more and more. What kinds of gold and silver hooks, big dragons, shrimp needles, and even what is the water, hibiscus, daughter rings, etc., are really varied and surprising. . These products are mainly intended to attract and deceive consumers and have no quality requirements or standards at all. Third, sales of loose tea can be bargained, and operators often use such means to cater to consumer psychology. On the other hand, high-priced gift packaging has become increasingly fierce. The value of these gift packages exceeds the value of tea by several dozen or even hundreds of times. These luxury packagings usually use high-grade materials such as mahogany and tin alloy to attract people's attention and sell teas that should not be preserved. In essence, this is a huge waste of limited resources. It is not desirable.

At present, relevant domestic authorities should be called upon to formulate corresponding policies to restrict the sales of loose tea. Actively guide tea production enterprises to create brand products, tea sales companies sell brand products, and consumers buy brand products. It is necessary to actively encourage the sale of pre-packaged tea products.