Distinction between Arabica and Robusta Coffee Beans by Hydroxycinnamic Acid Derivatives, Especially by p-Coumaroyltryptophan.

Abstract

Eleven chlorogenic acids, caffeoyltryptophan (CaT), and p-coumaroyltryptophan (CoT) in coffee beans (Coffea canephora var. robusta (Robusta) and C. arabica (Arabica)) and instant coffees on the market were analyzed by HPLC. Robusta beans contained more caffeoylferuloylquinic acids and CaT than Arabica beans. CoT was detected only in Robusta beans. The more intensely the coffee beans were roasted, the more all the chlorogenic acids decreased. CoT decreased the most slowly among phenols during roasting. Only instant coffees made of Robusta beans contained CoT. CoT becomes an indicator of Robusta beans.