## 4 Discussion
[4], and this volatile compound was not considered as a marker of citrus honey geographical origin. Alpha-4-dimethyl-cyclohexene-1-acetaldehyde is a volatile compound that has been considered to contribute to the aroma of Spanish citrus honey [8]. Indeed, in the present study this volatile compound was identified in all citrus honey samples, and in significantly lower amount (mg/kg) in the other nectar honey samples. Regarding esters, ethyl octanoate, ethyl nonanoate, and ethyl dodecanoate contribute to the geographical origin discrimination of citrus honey (Table 1). Methyl anthranilate (MA, 2-aminobenzoic acid methyl ester) was identified in all citrus honey samples in similar amounts (mg/kg), and therefore, could not be used as a potential indicator of geographical origin of citrus honey. MA is commonly used as a flavoring agent for its pleasant fruity odor. Its characteristic aroma can be described as fruity, concord grape, and musty, with a floral powdery nuance. This compound has been proposed as a fingerprint and an index of correct labelling of citrus honey [4; 6]. Indeed, [PERSON] et al. [6] reported that MA was correlated with certain volatile compounds, such as 1-para-menthene-9-al, limonene, dill-ether, and ethyl linalool, and slightly lower with the four lilac aldehyde isomers. In our case, MA was significantly correlated (r = 0.31, \(p\) = 0.043 \(<\) 0.05) only with lilac aldehyde C during the Pearson's correlation test, with some other potential correlations with volatile compounds such as lilac aldehyde D, \(\alpha\)-4-dimethyl-cyclohexene-1-acetaldehyde dill ether, and ethyl dodecanoate. Certain hydrocarbons such as heptane, octane, and nonane, have previously been identified in European unifloral honey samples[3; 4; 5; 19; 20; 21]. Among these volatile compounds, heptane and octane could contribute to the geographical discrimination of citrus honey, since these were identified in diverse amounts (mg/kg) (with respect, of course, to the geographical origin of citrus honey) (Table 1). It should be noted that the other nectar honey samples studied contained higher amounts (mg/kg) of octane. [PERSON] et al. [21] reported a higher amount (mg/kg) of octane for Spanish lesson honey compared to orange blossom honey. Several alkanes are common in the cuticle of honeybees, so the presence in honey could be due to an animal origin/activity and not exclusively from plants. Indeed, [PERSON] et al. [11] reported that aliphatic fatty acids probably originate from beeswax, and this could explain the presence of these compounds in honey. Dill ether ((3S,3 aS,7 aR)-3,6-dimethyl-2,3,3a,4,5,7a-hexahprobenzofuran) has previously been identified in Greek citrus honey [3; 5]. Dill ether was determined in a higher amount (mg/kg) in Moroccan citrus honey than in the other types (Table 1). As for ketones, 6-methyl-5-hepten-2-one and \(\beta\)-damascenone ((E)-1-(2,6,6-Trimethyl-1-cyclohexa-1,3-dienyl)but-2-en-1-one) were identified only in citrus honey from Greece. 6-Methyl-5-hepen-2-one has previously been identified as a volatile component in Spanish lemon and orange honey [21] in conformity with the results of the present study. \(\beta\)-damascenone was also identified in the other nectar honey samples. It is worth mentioning that \(\beta\)-damascenone was not identified in a recent study concerning the volatile profile of Spanish citrus, sunflower, and thyme honey [6], nor in a previous study concerning acacia, sunflower, and cilia honeys from Spain, Romania, and the Czech Republic [22]. Phenolic volatile compounds (benzeneethanol and benzeneacetonitrile) were only identified in studied nectar honey samples from countries other than Greece. Regarding 3,4,5-trimethylphenol, similar amount (mg/kg) was recorded for citrus and other nectar honey samples only from Greece. [PERSON] et al. [6] reported a similar isomer (2,4,5-trimethylphenol) to contribute to the aroma of Spanish citrus and thyme honey.