Temporal Analysis of Volatile Oil Compounds from Winter Season Flowering ‘Eureka’ Lemon

Abstract

The chemical compositions of Volatile Oil Compounds (VOCs) of Citrus limon (L.) Burm. ‘Eureka’ flowers were isolated at six stages of flower development using headspace extraction in the early of winter. The main floral headspace components were linalool, limonene, linalyl acetate, (E)-β-ocimene, γ-terpinene, (Z)-β-ocimene and myrcene were the highest VOCs for all blooming stages. The relative percentage of linalool as an oxygenated monoterpene was significantly increased to peak (56.19 %) at the early stage of the floral development, but in stage 5 the lowest quantity of linalool (28.27 %) was detected. The highest percentages of limonene, a major monoterpene hydrocarbons component of citrus volatile oils by headspace methods, were observed in stage 5 (33.9 %). Also the result indicated that the early stages of flower development (Stage 1 and 2) had the lowest quantity of this compound. Acetate esters are important contributors to the aroma of different Citrus flowers. The highest linalyl acetate was detected in stage 1 (21.24 %) and stage 5 (20.22 %) respectively. The lowest quantity of this compound was detected in stages 4 and 3 respectively. (E)-β-ocimene was significantly increased to peak (6.44 %) at the stage 5 of the floral development and accumulated during the late stages of the flowers development (stage 3-6). These results present clear proof that the content of some main volatiles did not constantly increase during flower blooming, and that volatiles have a large influence during flower maturity, maybe related to their different roles during development such as defense against pathogen and attraction of pollinating agent.