The effects of brewing water on the sensory attributes and physicochemical properties of tea infusions made from Chinese teas were investigated. The tea infusions brewed in water with higher pH and total dissolved solids (TDS), generally had a darker color and lower overall sensory acceptability. Moreover, those infusions had less catechins, particularly galloylated-catechins, and lower antioxidant capacity. The teas with less fermentation contained more galloylated-catechins and had higher antioxidant capacity, but were much more susceptible to high mineral brewing water. Green tea was proved to be the most susceptible one, whereas dark tea the most stable one. Green tea infusions prepared with higher pH/TDS water were more rapidly oxidized, resulting in a darker color due to polymerization of catechins, when exposed to the air. These findings suggested that low mineral brewing water was better for Chinese tea, both from the sensory and health benefit perspectives.
Excessive consumption of caffeine presents health risks, necessitating the development of effective decaffeination methods in the food industry. This study introduced an innovative CMP aerogel that incorporated montmorillonite into a carboxymethylcellulose/polyethyleneimine framework to selectively decaffeinate without compromising the food's original flavor. The CMP aerogel achieved a caffeine adsorption capacity of 18.59 mg/g, primarily driven by electrostatic interactions and hydrogen bonding, as well as additional processes such as chelation, cation exchange, and complexation. The adsorption kinetics followed a pseudo-second-order model, with the adsorption data fitting the Langmuir isotherm, indicating monolayer adsorption. Notably, the CMP aerogel demonstrated excellent stability and reproducibility, maintaining over 90 % of its initial adsorption capacity after seven cycles. Importantly, it effectively reduced caffeine content in black tea infusions while preserving key attributes such as tea color, catechins, and aroma. The retention rate of catechins was 66.2 %, the number of flavor compounds decreased from 109 to 91 and the total retention rate was 58.7 %. These findings highlight the aerogel's promising potential as a practical decaffeination solution, providing valuable insights into alternative methods for caffeine removal, particularly in the tea industry.
危险品化学品经营许可证（带存储）