## 4 Discussion
Seven terpenes, 2,6,6-trimethyl-bicyclo [3.1.1]hept-2-ene (\(\alpha\)-pinene), 1-methyl-4-(1-methyl-ethyl) benzene (para-cymene), dll-limonene ((4\(R\))-1-methyl-4-prop-1-en-2-ylcyclohexene), her boxide (isomer II) (5-isopropyl-2-methyl-2-vinyltetrahydro), hotrienol ((E)-3,7-dimethylocta-1,5,7-trien-3-ol), cis-linalool oxide (2-[(2S,5R)-5-ethehenyl-5-methyloxolan-2-yl]propan-2-yl carbamates), andlinalo (3,7-dimethylocta-1,6-dien-3-ol), were also identified in diverse amounts (mg/kg) (Table 1), in conformity with previous studies in the literature concerning Greek and Spanish citrus honey [3; 6; 7; 20]. Trepenoids comprise the major components of essential oils of the flowers and fruits of the _Citrus_ genus [4] and the presence of these volatile compounds in citrus honey is associated with the honeybee feeding on the nectar of these plant materials. Driving the hypothesis further, the potential of volatile compounds in combination with chemometrics for the geographical and botanical origin discrimination of honey is really very satisfactory. Previous studies in the literature are in accordance with the results and the hypothesis presented in the present study. More specifically, [PERSON] et al. [8] differentiated Spanish citrus, rosemary, laverde, thyme, eucalyptusptus, and heather honey using inalool derivatives, limonyl alcohol, sinensal isomers, and \(\alpha\),4-dimethyl-3-cyclohexene-1-acetaldehyde, acetoin, 5-hydroxy-2,7-dimethyl-4-octanone, para-cymene derivatives, 3-caren-2-ol, spathoul, hexanal, meridol oxide, coumarin, hexanol, benzene, and phenolic compounds in combination with PCA. The first four components (PC1-PC4) explained 71% of the total variance. [PERSON] et al. [11] reported that 3,8-para-menthatiene; cyclopropyl-lidenomethylbenzene; 1,1,6-trimethyl-1,2-dihydronanghthenlee; 1,2,4-trimethylbenzene; \(\alpha\)-pinene; isopropyl 2-methylbutanoate; cypene; 2,6-dimethyl-1,6-octadiene; 3-methyloctane; 1-(1,4-dimethyl-3-cyclohexen-1-yl)ethanoneone; terpinolene; ethyl 2-phenylacetate; naphthalene; and seven unknown compounds could be used to classify Argentinean honey according to their geographical origin with a prediction success of 96% using principal component analysis (PCA), redundancy analysis (RDA), and linear discriminant analysis (LDA). [PERSON] et al. [19] reported that the application of PCA and hierarchical cluster analysis, as a comparative multivariate technique, on the volatile composition of Turkish pine honey showed that nonanal, nonanol, octanol, decanal, phenylacetaldehyde, benzaldehyde, octanal, \(\alpha\)-pinene, 4-oxoisophorone, methyl salicylate, isopropyl myristate, limonene, and \(\beta\)-damascenone could be used as marker compounds of these type of honey. The first two components of PCA (PC1 and PC2) explained 41.3% of the total variance. [PERSON] et al. [6] applied PCA on the volatile composition of Spanish citrus, sunflower, and thyme honey, and reported that methyl anthranilate, 1-para-menthene-9-al, limonene, dill-ether, and ethyl linalool could be used for the differentiation of honey. The total variance explained by the first two components (PC1 and PC2) was 67%. However, there is a lack in the relevant literature for a conclusive index originating from volatile compound composition to be used for discrimination purposes (geographical or botanical origin determination). A New Index for the Geographical Origin Discrimination of Citrus Honey Based on the Ratio of Semi-Quantitative Data of Specific Volatile Compounds  
The volatile compounds (variables) that contributed dynamically to the discrimination of citrus honey according to geographical origin were those with the higher absolute correlation during LDA, as LDA is a more efficient chemometric technique for discrimination purposes compared to PCA [16; 17; 18].