Monitoring Content of Components with Functional Benefits in Coffee Made with Different Roasting Times

Importance of the Topic

Coffee contains a range of bioactive components such as trigonelline, chlorogenic acid, pyrocatechol and caffeine, which contribute to its flavor and potential health benefits. Understanding how roasting alters these compounds is critical for product development, quality control and nutritional studies in coffee research.

Objectives and Study Overview

This study demonstrates a streamlined workflow for monitoring changes in key coffee components as a function of roasting time. By coupling high-performance liquid chromatography (HPLC) with a multi-data reporting tool, the authors aimed to quantify multiple analytes simultaneously and automatically compile results into convenient reports.

Analytical Methods and Instrumentation

A Shimadzu Nexera™ lite HPLC system equipped with a Shim-pack Scepter™ PFPP column (150 × 4.6 mm, 3 μm) and a PDA detector (SPD-M40) was used. The gradient mobile phase consisted of 20 mmol/L sodium phosphate buffer (pH 2.6) and acetonitrile at a flow rate of 1.0 mL/min. The column temperature was held at 25 °C and injection volume was 5 µL. Samples were prepared by brewing 10 g of ground coffee in 150 mL boiling water, filtering through 0.2 µm membranes, and diluting tenfold with ultrapure water. Roasting was performed at 250 °C for 150 to 210 seconds in 20 s increments.

Key Results and Discussion

The calibration curves for trigonelline, pyrocatechol, chlorogenic acid, caffeine and caffeic acid showed excellent linearity (r2 ≥ 0.99999) over their respective concentration ranges. Chromatographic analysis at 270 nm and 325 nm revealed that as roasting time increased, trigonelline and chlorogenic acid levels decreased, while pyrocatechol formation increased. Caffeine concentration remained essentially constant across all roasting durations. These trends reflect the thermal degradation and transformation pathways of coffee’s functional constituents.

Benefits and Practical Applications

By employing the multi-data report function within LabSolutions™ DB/CS software, analysts can automatically generate consolidated spreadsheets and graphical plots of component concentrations versus roasting time. This automation minimizes transcription errors, reduces manual labor and accelerates data interpretation, making it valuable for routine quality assurance, product optimization and research workflows in food science.

Future Trends and Potential Applications

• Integration of advanced detectors (e.g., mass spectrometry) for broader compound coverage.
• Real-time monitoring of roasting processes using inline HPLC or sensor arrays.
• Machine learning algorithms applied to multi-data outputs for predictive roasting profiles and flavor optimization.
• Expansion to other food matrices and functional ingredients beyond coffee.

Conclusion

The combination of a PFPP-based HPLC method and automated reporting significantly enhances the efficiency and reliability of quantifying coffee’s functional compounds during roasting. This approach supports rapid decision making in both research and industrial settings.

References

1. M. Kamiyama, J.K. Moon, H.W. Jang, T. Shibamoto, Journal of Agricultural and Food Chemistry, 63(7), 1996–2005 (2015).
2. Shimadzu Application News No. 01-00286-EN, First Edition: Jun. 2022.