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

Area of Science:

• Food Science
• Agricultural Chemistry
• Phytochemistry

Background:

• Black tea is a popular beverage with known health benefits.
• The chemical composition of tea influences its health effects.
• Black tea production involves several stages: withering, rolling, oxidation, drying, and sorting.

Purpose of the Study:

• To investigate the effects of black tea processing stages on its physical and bioactive properties.
• To understand how processing influences key quality parameters and bioactive compounds.
• To provide insights for optimizing black tea production to maintain beneficial properties.

Main Methods:

• Samples were collected at each stage of black tea production.
• Physical properties (moisture, color, pH) were analyzed.
• Bioactive properties (total phenolics, antioxidant activity) and fatty acid profiles were determined.

Main Results:

• Processing stages significantly affected moisture content, color parameters (L*, a*, b*), pH, total phenolic content, and antioxidant activity (p < 0.01).
• Antioxidant activity was highest in fresh tea and decreased during processing, with lowest levels observed during drying (water extracts) and drying/sorting (ethanol extracts).
• Palmitic acid was the dominant saturated fatty acid, alongside myristic and capric acids. Oleic, heptadecenoic, and eicosenoic acids were identified as unsaturated fatty acids.

Conclusions:

• Black tea processing significantly alters its physicochemical and bioactive characteristics.
• Optimization of processing steps is crucial for preserving the functionality of bioactive compounds in black tea.
• Understanding these effects can guide the production of higher quality black tea with enhanced health benefits.