High-Speed Analysis of Methylated Catechin in Benifuuki Green Tea

High-Speed Analysis of Methylated Catechin in Benifuuki Green Tea

Significance of the Topic

Benifuuki green tea is rich in O-methylated catechin, a derivative of epigallocatechin gallate with demonstrated antiallergic and anti-inflammatory properties. Reliable quantification of this compound supports quality control, functional food claims and regulatory compliance in the tea industry.

Objectives and Study Overview

This report presents a comparison between the established Japanese Agricultural Standard (JAS) HPLC method for methylated catechin determination and a high-speed variant using upgraded column technology. Goals include reducing analysis time and solvent consumption while maintaining accuracy, precision and linearity.

Methodology and Instrumentation

Both methods employ reversed-phase high-performance liquid chromatography with UV detection at 272 nm. Sample preparation follows JAS guidelines: extraction of ground tea in phosphoric acid/ethanol/water, filtration and dilution. Two analytical protocols were evaluated:

• JAS-compliant method: Nexera X3 system with Shim-pack GIST C18 column (150 × 4.6 mm, 5 μm), 1 mL/min, gradient from 23% to 70% organic over 30 min, 10 μL injection.
• High-speed method: same system with Shim-pack GIST-HP C18 column (75 × 3.0 mm, 3 μm), optimized gradient over 7.5 min, 4 μL injection.

Main Results and Discussion

Calibration across 1–50 mg/L showed excellent linearity (R2 ≥ 0.99999) for both methods. The high-speed protocol trimmed run time and mobile phase use to roughly one-quarter of the JAS method while preserving peak resolution and reproducibility (retention time RSD ≤ 0.05%, area RSD ≤ 0.79%). Analysis of a commercial Benifuuki sample yielded 12 g/kg methylated catechin with both approaches, confirming equivalence.

Benefits and Practical Applications of the Method

• Faster turnaround for routine quality control and research laboratories.
• Reduced solvent consumption and waste generation, lowering operational costs.
• Maintained compliance with regulatory standards while increasing throughput.

Future Trends and Opportunities

Further advances may include ultra-high-pressure columns for sub-2 μm packing, automation of sample preparation and coupling to mass spectrometry for enhanced selectivity. Integration into inline quality monitoring and digital laboratory workflows could accelerate functional ingredient screening.

Conclusion

The high-speed HPLC method using Shim-pack GIST-HP C18 column delivers equivalent analytical performance to the JAS-compliant protocol for O-methylated catechin in Benifuuki tea, with significant time and solvent savings. This streamlined approach is well suited for high-throughput screening and routine quality assurance.

Reference

1. Maeda-Yamamoto M. et al. Nippon Shokuhin Kagaku Kogaku Kaishi, 48, 64-68 (2001).
2. Japanese Agricultural Standard JAS 0002, Ministry of Agriculture, Forestry and Fisheries (2018).
3. Homura Y. et al. Nippon Shokuhin Kagaku Kogaku Kaishi, 63(7), 312-318 (2016).