A comprehensive study on determination of chemical composition of kumquat (Fortunella margarita L.) fruits

Kumquat (Fortunella margarita L.) is a group of small-sized fruits with a typical aroma. In this study, it was aimed to determine the chemical composition of kumquat fruit including β-carotene, sorbitol, sugars, organic acids and phenolics. According to High-Performance Liquid Chromatography (HPLC) analysis, β-carotene content was found to be 0.43 mg 100 g-1 in fresh fruit. Sucrose accounted for more than half of the sugar content with a ratio of 3.19 mg 100 g-1. Citric acid was the most abundant organic acid in kumquat. A total of 14 phenolic compounds were investigated to reveal the phenolic composition of F. margarita and the results showed that it had a great diversity of phenolics. Gallic acid (277.3 mg 100 g-1), procyanidin B1 (119.3 mg 100 g-1) and epigallocatechin (89.3 mg 100 g-1) were the major phenolic compounds identified in the whole fruit. As the fruit was eaten without peeling, the essential oil of the peel (PEO) was also analyzed by Gas Chromatography-Mass Spectrometry (GC-MS). It was determined that the PEO was a mixture of monoterpenes, sesquiterpenes, oxygenated terpenic compounds, esters and aldehydes. Limonene (83.8%), a monoterpenic substance, was the major aromatic component in the PEO, followed by β-myrcene (6.7%), germacrene D (3.3%) and α-pinene (1.8%). This work has shown that kumquat fruit is a natural source for bioactive compounds.