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2025.12.22
Pursuit of superior flavor and taste Plant science StoryWhat are the compounds in green coffee beans that change depending on the maturity of the coffee cherries?
Coffee, a beverage enjoyed around the world, is made through roasting and extraction of green coffee beans. Suntory has succeeded in clarifying the key compounds in green coffee beans that change according to the maturity of the coffee cherries.
This article is a re-edited version of an article that appeared on our corporate website in 2014. The position names, department names, and photos in the article are, in principle, current as of the time of publication (2014).
Article Summary
To craft truly delicious coffee beverages , we began studying how coffee cherry maturity influences metabolites in green coffee beans. We adopted a technique known as metabolomics to comprehensively track changes in the content of thousands of components. As a result, we were the first in the world to identify that tryptophan, an amino acid found in green beans extracted from immature fruit, decreases with maturity and serves as a marker for predicting ripeness. Furthermore, tryptophan was found to be the source of an unpleasant immature odor generated during roasting.
A closer look at the changes in green coffee beans according to the ripeness of the coffee fruit
With the earnest desire to manufacture superior flavor and tasting coffee beverages, Suntory is forging ahead with research by looking at plant materials.
Coffea produces brightly colored cherries whose color changes as they ripen. The seeds of those coffee cherries become green coffee beans that are the raw materials for coffee, but the changes in the green coffee beans dependent on maturity were still not clear.
For that reason, we began research focusing on the metabolites in green coffee beans that change according to the maturity of the coffee cherries.
A comprehensive analysis of the thousands of compounds contained in green coffee beans
There are numerous compounds in green coffee beans, some of which exist in very few numbers. Since some compounds significantly impact the coffee’s maturity regardless of the amount contained in the coffee beans, to search for compounds that are key to maturity a cutting-edge analytical technology was required that is capable of detecting even minute amounts. Therefore, we newly implemented a highly precise technology called metabolomics* that is used in medicine when diagnosing diseases from traces of blood and saliva. This technology makes it possible to comprehensively detect changes in the amounts of thousands of compound types, including those that exist in minute quantities.
*This technology comprehensively and objectively analyzes metabolites, which are chemical compounds produced in plant and animal cells through biological activity.
Identification of key compounds that changes depending on maturity!
We harvested coffee cherries of different maturities from nine varieties grown in a coffee plantation of collaborative research institute, then analyzed the compounds in the green coffee beans using metabolomics.
Analysis results showed that tryptophan, an amino acid, is contained in green coffee beans from immature cherries, regardless of the variety, and that the amount decreases as the cherries ripen. Though it was known that tryptophan is the precursor to the growth hormone called auxin in rice plants and corn, this research discovered for the first time in the world that it is also an important compound in the maturation process of coffee cherries. Furthermore, we also found that the thermal decomposition of tryptophan gave indole and methylindole, which cause an unpleasant immature odor in the roasting process.
Our challenges
For manufacturing superior flavor and tasting beverage, understanding the nature of plant materials is important. We understand the mechanisms of substances and phenomena, and cooperate on the project with manufacture teams. Based on fundamental principles, we challenge to develop practical technologies that lead to new manufacturing. We are discovering the hidden potential of nature’s gifts and enhancing the attractiveness of materials to contribute to the creation of new value.
[News Release] World’s First Elucidation of the Strong Correlation between Tryptophan in Coffea Arabica Green Beans and the Maturity Level of Coffee Cherries, a Determinant of Coffee Flavor Quality (Sept. 11, 2014)
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