Characterization of phenolic compounds in sweet lime (Citrus limetta) peel and freshly squeezed juices by LC-DAD-ESI-MS/MS and their antioxidant activity

Abstract

Sweet lime (Citrus limetta) is one of the citrus species and it is generally consumed fresh or processed to fruit juice. The squeezing method of fruit is an important factor affecting the quantity and composition of phenolic compounds of the juice. The aim of this study was to identify and quantify the phenolic compounds and determine the antioxidant activities of sweet lime peel and juices. For this purpose, sweet lime juices were prepared using two different methods. Firstly, sweet lime fruits were hand-squeezed without peeling. Secondly, fruits were hand-squeezed after the manual removal of the peel. The phenolic compounds of the peel and the two types of juices were analyzed by LC-DAD-ESI-MS/MS. Twenty phenolic compounds were determined in all extracts, 18 of which were flavonoids and two were phenolic acids. The major compound was hesperidin both in the peel and juices. The procyanidin B dimer and luteolin were detected for the first time in sweet lime peel and juices in the present study. The amount of phenolic compounds of the peel was significantly higher than those of the juices. The total phenolic contents of the sweet lime juice increased about 13% from 444.55 to 502.54 mg/L due to the effect of the peel. The antioxidant capacity of the peel was found to be higher than those of the juices resulting from its high phenolic content.