## 3 Significance of Volatile Organic Compounds in Honey  
### Determination of Floral and Geographical Origin of Honey  
Honey is often marketed as mixed-floral honey with a blend of flavors, consequently, its botanical origin which greatly influences the consumer preference, remains difficult to determine [23]. The floral origin of honey is an important characteristic in the evaluation of its quality. Indeed, the estimation of honey quality by consumers depends on its organoleptic characteristics, which is strongly dependent on its botanical origin and to some extent also on its geographical origin [2]. Honey of the same floral source can vary due to seasonal climatic changes or to a different geographical origin [3]. Monofloral or unifloral honey is produced from nectar that is derived either wholly or mainly from a single species or plant and therefore is comprised of specific VOCs [10, 28]. Accordingly, VOCs could be used to discriminate between monofloral honeys from different floral origins given that the high number of VOCs gives a distinct profile that could represent the fingerprint of each honey type. Traditionally, the botanical source of honey is determined by microscopic examination of its pollen, a technique known as melissopalinology [35]. Nevertheless, melissopalinology is expensive, time-consuming and is strongly dependent on the qualifications and judgment of the analyst [2, 36]. In addition, there is the need for a pollen library; industrial infiltration may also affect the accuracy and precision of the technique [2]. Moreover, there is great variability in the nectar contribution of any particular flower compared to the quantity of its pollen found in honey. In spite of the fact that specific pollen could be present in a honey, its presence could be low in some honey types (citrus, lavender and rosmear), consequently a wider range of markers necessary to ascertain the origin of honey becomes inevitable [37]. [PERSON] _et al_. [38] pointed out that in some cases pollen analysis could be of no use especially when the honeys are derived from sterile plants. [PERSON] _et al_. [4] reported that it is more difficult to determine the floral origin of honeydew honey because palynological analysis could not be conducted considering its source of production. Therefore, there is a tendency to replace pollen analysis by profiling analytical and/or physicochemical markers for honey discrimination. Besides the other parameters that have been extensively studied for the recognition of floral origin, VOCs is one of the main factors for differentiating honeys from different botanical/ floral origin as well as geographical origins [36]. Once VOCs have been extracted by any of the aforesaid techniques and subsequently analyzed by GC-MS, typically generates a complex chromatographic profile, with multiple peaks of different intensities and the presence of characteristic compounds mixed with non-characteristic ones (mainly arising from impurities, industrial processes, a blend of different products, _etc_). From this complex profile, it is necessary to identify compounds which are characteristic of a given source, as a mandatory step to assess the origin of a food product. With GC-MS analysis, initial identification of the compounds would be achieved by comparing their mass spectra with those of the NIST Mass Spectral Data Base [28] and or WILEY library [2]. The identity of chosen volatile compounds could be additionally verified on the basis of conformity of retention times and mass spectra with standards [35]. However, there is disagreement over which compounds could serve as floral markers for a given honey type since differences exist between plant varieties, geographical origins or beekeeping practices [4]. Also, methods of extracting the volatile fractions may display a varying degree of selectivity and effectiveness depending on the compounds involved [19].