Scientists find genes that determine the quality of coffee

In order to earn more income, coffee growers have been committed to producing higher quality products. But getting high-quality coffee beans means a better understanding of biological processes-flowering, ripening, etc.-that determine the final quality of the product.

Many compounds (sugar, fat, caffeine, etc.) determine the quality of coffee. Their content in coffee beans is the decisive factor. Among them, sucrose plays the most important role in the sensory quality of coffee, because the decomposition of sucrose in the roasting process produces a variety of aromas and other tastes.

Since 2001, CIRAD and Brazil's IAPAR have jointly studied the ripening process of coffee beans. They found a decisive enzyme in sucrose metabolism, which scientists studied using molecular biology and biochemical techniques with the support of the University of Campinas in Brazil. The results showed that this sucrose synthase determined the deposition of sucrose in coffee beans. There are at least two forms of sucrose synthase, which are compiled by two different genes: SUS1 and SUS2.

Scientists analyzed the expression of these genes in a variety of tissues of growing coffee beans. The results showed that SUS2 determined the sucrose deposition during ripening. SUS2 is related to sucrose decomposition and energy production. Another part of the study is genetic diversity, which explains why there are differences between different types of coffee. This helps to confirm the content of sucrose and ultimately affect the quality of coffee.

The above research results have been applied at present. Scientists found that coffee grown in shadows had higher activity of sucrose synthase and sucrose phosphate synthase. The final quality of these coffees may also be related to other factors, such as lipids.