## 1 Introduction  
Honey is one of the oldest untreated natural foods, part of cooking traditions, and used as a sweet additive in many cultures throughout the world [1]. Due to its particular chemical content and nutraceutical properties, honey has been also used in medicine; its anti-inflammatory, anti-microbial, and anti-oxidant properties have been demonstrated in specific studies about honey's ability to reduce cardiovascular and gastrointestinal diseases, as well as to positively influence human health [2, 3]. Honey is produced by honeybees from the nectar of plants, as well as from honeydew, and can be distinguished into monofloral or polyfloral honey, depending on whether it is derived mostly from one plant species or if it derives from different botanic sources. According to international food standards (_Codex Alimentarius Commission._, 2001) [4], monofloral honey should possess organoleptic, physical, chemical, and microscopic properties related to the plant of origin. However, these characteristics are not easily determined and, until now, a univocal and unambiguous method to clearly identify the botanic origin of honey is still missing [5]. Nevertheless, one of the most used technique to assess the botanic origin of honey is the traditional microscopic analysis of pollens present in honey samples, called melissopalynology [6; 7]. Focusing on its chemical composition, honey can be considered a viscous fluid made of sugars (saccharides) (70%-80%), water (10%-20%), and about 200 different minor components, such as minerals, proteins, amino acids and enzymes, vitamins, phenolic and other organic acids, flavonoids, lipids, and volatile compounds. Despite these general chemical features, honey is a very complex food matrix, since the presence of particular molecular markers and their concentration depend on many factors: not only the botanic and geographic origin of the plants, but also the season and climate conditions, the bee species, and soil characteristics [5]. Over the last twenty years, numerous analytical methods were proposed to investigate the chemical and physical properties of honey with the aim to discriminate among different botanic and geographic origins [8; 9; 10; 11; 12; 13]. Sugars' components and saccharides' profiles are mainly determined by chromatographic methods, such as gas chromatography coupled with mass spectrometry (GC-MS) [8], ion chromatography with an amperometric pulsed detector (HPAEC-PAD) [10], and high performance liquid chromatography (HPLC) [5; 8]. Several analytical methods were optimized to study proteins and the enzymatic content in honey, as well as the amino acids profile, mainly by means of HPLC methods and high-resolution two-dimensional electrophoresis [8]. As also reported in a comprehensive review [5], the combination between chromatographic techniques and multivariate statistical analysis identified several amino acids as possible floral origin markers (i.e., phenylalanine and tyrosine as characteristic markers for lavender honey). Among volatile and semi-volatile organic compounds, whose interests are related to the aroma and fragrance quality of honey, seven groups of compounds were identified: aldehydes, ketones, acids, alcohols, esters, linear hydrocarbons, and cyclic compounds [5]. The determination of volatile compounds in honey is not an easy task, since different isolation and extraction techniques, which usually precede the GC analysis [5; 8], have proved to largely influence the final quantification of these minor components. Several progresses both in the multivariate data analysis and extraction techniques are at the basis of recent studies on the correlation between the presence of specific volatile compounds (i.e., derivatives of \(\alpha\)-ionone) and the botanic origin (i.e., _Eucalyptus_ plant) of honey samples [13]. Another fundamental class of minor bioactive compounds is that of polyphenols, which can be classified into three sub-groups: flavonoids, cinnamic acids, and benzoic acids [14].