Characterisation of Volatile Compounds in Kumquat and Calamansi Peel Oil Extracts

Abstract

Kumquat and calamansi are two exotic citrus fruits that are integral in Asian cuisine. While they possess excellent flavour profiles and potential health benefits, they have not been as extensively studied as other citrus fruits. In this study, the peel oil extracts of four kumquats (Jindou, Youpi, Huapi and Suichuan) and two calamansis (the Philippines and Indonesia) were analysed using gas chromatography-mass spectrometry (GC/MS). Principal component analysis (PCA) revealed a distinct separation of kumquat and calamansi, with Huapi kumquat differentiated from the other three kumquats based on their volatile profiles. Subsequently, Youpi kumquat and Philippines calamansi were further selected for aroma extract dilution analysis (AEDA), revealing 36 and 34 key odourants, respectively. Linalool and β-pinene were the two major key odourants in Youpi kumquat, while limonene and linalool were determined to have the greatest contribution to the aroma of Philippines calamansi. With the aid of a GC coupled with a quadrupole time-of-flight MS (QTOF/MS) detector, indole was identified in Youpi kumquat and reported for the first time as a key odourant in kumquat. This study enriches existing knowledge of these exotic citrus fruits, allowing for further applications of these fruit aromas in flavour or perfumery.