Changes of some bioactive and physicochemical properties during the black tea processing

Abstract

In this research, some physical and bioactive properties of tea samples collected from every processing stage of black tea production were investigated. The processing stages were significantly effective on the investigated properties (moisture content, color parameters [L * , a * , and b * ], and pH values the total phenolic substance, antioxidant activity) (p < 0.01). The antioxidant activities were found to be at a high level in fresh tea but decreased during the processing stages. Furthermore, the lowest activity was observed in the drying stage for extracts prepared with water and in the drying and sorting stages for extracts prepared with ethanol. In addition, it was determined that palmitic acid, myristic acid, and capric acid as saturated fatty acids, oleic acid, heptadecenoic acid, and eicosenoic acid as unsaturated fatty acids formed the fatty acid profile. Palmitic acid was determined to be the dominant fatty acid in tea samples. K E Y W O R D Santioxidative, black tea, fatty acid, processing Practical Application: Tea is a beverage known to have positive health effects.The chemical structure of tea is very effective in providing these positive effects on health. Black tea production takes place in five stages in general terms (withering, rolling, oxidation, drying, and sorting stages) after the harvesting. These processes are very effective in the quality properties of tea. This research provides information about effects of processing stages on black tea. Our results demonstrate that processing was significantly effective on the physicochemical and bioactive properties of tea. Functionality of bioactive compounds could be maintained by optimization of the applied processes.

Determination of C═C Positions of Unsaturated Fatty Acids in Foods via Ambient Reactive Desorption Ionization with Water Dimer Radical Cations

“…Similarly, the contents of linoleic acid in Indian Darjeeling tea, Jiangxi Ning black tea, and Fujian Lapsang Sauchong were quantified to be ∼233.5, ∼429.6, and ∼223.4 μg/g, respectively, and the contents of linolenic acid in Indian Darjeeling tea, Jiangxi Ning black tea, and Fujian Lapsang Sauchong were quantified to be ∼566.4, ∼ 494.2, and ∼504.9 μg/g, respectively. These were similar to what is described in the previous literature …”

Comprehensive analysis of the effect of etiolated tea cultivars and harvest seasons on volatile compounds and in vitro antioxidant capacity in steamed green teas

“…The highest relative content of acids in spring tea was attributed to the higher relative content of hexadecanoic acid (27.69%–40.54% of the total volatile compounds). Hexadecanoic acid is the major fatty acid in tea ( Balaban et al, 2022 ) and the most abundant aroma component in dark tea ( Lv et al, 2017 ), contributing significantly to the unique aroma of oolong tea ( Wang et al, 2016 ), which is perceived sensorially as “slightly waxy/fatty” aroma. Compared with summer tea and autumn tea, spring tea had the highest relative content and types of alkenes, with higher average relative content of (+)-δ-cadinene (31.65 μg/L), cadinadiene (10.29 μg/L), and limonene (9.78 μg/L).…”

Hot-Air Drying Significantly Improves the Quality and Functional Activity of Orange Black Tea Compared with Traditional Sunlight Drying

“…Black tea contains a large number of functional active substances, such as tea polyphenols, amino acids, tea polysaccharides, and alkaloids, with the highest content of tea polyphenols, about 10~20% [1]. Additionally, black tea has a variety of health benefits, such as antioxidant, anti-inflammatory, and antitumor functions [2]. Moreover, the polyphenols in black tea were reported to have good antioxidant and anti-inflammatory effects [3].…”