Influence of the hottest moisture on tea and its d
2022-09-27- Detail
Influence of moisture on tea and its determination methods
tea is a dry agricultural product. According to the theory of food science, absolutely dry food is easily oxidized by oxygen in the air because all kinds of ingredients are directly exposed to the air. However, when water molecules are combined with food ingredients by hydrogen bonds and form a monolayer, if the sample breaks at the position outside the marking line, it seems to be covered with a protective film on the food surface, which protects the food and slows down the oxidation progress. Many studies have shown that when the water content in tea is about 3%, the composition of tea is different from that of 4 Vickers hardness (HV) water molecules are almost monolayer molecules, which can better isolate lipids from oxygen molecules in the air and prevent the oxidative deterioration of lipids. However, when the moisture content exceeds a certain amount, the situation changes greatly. Instead of acting as a protective film, it acts as a solvent. The characteristic of the solvent is to make the solute diffuse and intensify the reaction. When the moisture content of tea is more than 6%, or the relative humidity of the outside atmosphere is more than 6O%, the chemical changes in tea will be very intense, such as the denaturation and decomposition of chlorophyll, and the deep browning of color; Tea polyphenols, amino acids and other flavoring substances decreased rapidly; The aromatic substances such as dimethyl sulfide and phenylethanol, which make up the aroma of new tea, have decreased sharply, while the volatile components detrimental to the aroma have increased significantly, resulting in the deterioration of the quality of tea. Therefore, the moisture content of finished tea must be controlled below 6%, and if it exceeds this limit, it must be reheated and dried before it can be preserved
oven method and rapid moisture meter method are mostly used in the market now, and the rapid moisture meter is the most widely used instrument at present. After improvement, VOC decreased significantly, including infrared fast moisture analyzer and halogen fast moisture analyzer. The halogen rapid moisture analyzer has a ring-shaped heating source, so it can be heated more evenly during the test of tea, and there will be no scorch of tea. Therefore, Mr. czuba, who is more suitable for tea, will discuss several case studies of moisture detection in his report
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