Extraction Techniques for Bioactive Compounds in Tea Systems

Tea is a rich source of bioactive compounds, notably polyphenols and flavonoids, which underpin its health benefits and commercial value. Extraction techniques range from conventional solvent‐based maceration and heat‐reflux methods to advanced green technologies such as ultrasound‐assisted extraction, subcritical water extraction and supercritical CO₂ extraction. Key process variables include solvent polarity, temperature, extraction time, particle size and pressure. Optimisation strategies often employ statistical designs to maximise yield and preserve antioxidant activity while minimising degradation and solvent use. Analytical techniques such as high‐performance liquid chromatography and spectrophotometric assays (DPPH, ABTS, FRAP) are essential for profiling extract composition and bioactivity. Emerging approaches integrate extraction with downstream processing—such as microencapsulation—to stabilise sensitive compounds, valorise spent tea waste and enable functional food or nutraceutical applications.

Research from Nature Portfolio

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Research from all publishers

Recent studies have optimised recovery of polyphenols from spent black and green tea leaves using response surface methodology, revealing that extraction temperatures nearing 94 °C, extraction times of about 80 min and ethanol–water ratios around 55–60 % maximise total phenolic content and antioxidant activity. In green tea, comparisons of maceration, ultrasound and accelerated solvent extraction across various solvent systems demonstrated that a 1 : 1 ethanol–water mixture consistently yields the highest catechin concentrations and radical-scavenging capacity, irrespective of extraction mode. Subcritical solvent extraction of spent black tea at elevated temperatures (circa 180 °C) with around 70 % ethanol, followed by spray‐dry microencapsulation, has been shown to produce stable phenolic‐rich powders with over 90 % retention of antioxidant capacity during accelerated storage. These developments illustrate a growing trend towards process intensification, waste valorisation and product stabilisation for functional ingredient manufacture.

Extraction Techniques for Bioactive Compounds in Tea Systems publication trend

The graph below shows the total number of articles in extraction techniques for bioactive compounds in tea systems across all publications each year (not limited to Nature Index journals).

Technical terms

Polyphenols: A class of plant secondary metabolites with multiple phenolic groups, responsible for antioxidant and health‐promoting properties in tea.

Response Surface Methodology (RSM): A statistical technique for modelling and optimising complex processes by evaluating interactions between multiple variables.

Subcritical Solvent Extraction: A method using liquid solvents at temperatures and pressures below their critical point to enhance solubility and diffusion of target compounds.

Microencapsulation: A process that encloses bioactive agents within a protective coating to improve stability, control release and facilitate incorporation into formulations.

References

1. From Spent Black and Green Tea to Potential Health Boosters: Optimization of Polyphenol Extraction and Assessment of Their Antioxidant and Antibacterial Activities. Antioxidants (2024).
2. Optimization of Ultrasonic Extraction of Phenolic Antioxidants from Green Tea Using Response Surface Methodology. Molecules (2013).
3. Influence of particle size and extraction solvent on antioxidant properties of extracts of tea, ginger, and tea–ginger blend. Food Science & Nutrition (2017).
4. Valorization of spent black tea by recovery of antioxidant polyphenolic compounds: Subcritical solvent extraction and microencapsulation. Food Science & Nutrition (2020).