Volatile Compounds in Honey: A Review on Their Involvement in Aroma, Botanical Origin Determination and Potential Biomedical Activities

Volatile organic compounds (VOCs) in honey are obtained from diverse biosynthetic pathways and extracted by using various methods associated with varying degrees of selectivity and effectiveness. These compounds are grouped into chemical categories such as aldehyde, ketone, acid, alcohol, hydrocarbon, norisoprenoids, terpenes and benzene compounds and their derivatives, furan and pyran derivatives. They represent a fingerprint of a specific honey and therefore could be used to differentiate between monofloral honeys from different floral sources, thus providing valuable information concerning the honey’s botanical and geographical origin. However, only plant derived compounds and their metabolites (terpenes, norisoprenoids and benzene compounds and their derivatives) must be employed to discriminate among floral origins of honey. Notwithstanding, many authors have reported different floral markers for honey of the same floral origin, consequently sensory analysis, in conjunction with analysis of VOCs could help to clear this ambiguity. Furthermore, VOCs influence honey’s aroma described as sweet, citrus, floral, almond, rancid, etc. Clearly, the contribution of a volatile compound to honey aroma is determined by its odor activity value. Elucidation of the aroma compounds along with floral origins of a particular honey can help to standardize its quality and avoid fraudulent labeling of the product. Although only present in low concentrations, VOCS could contribute to biomedical activities of honey, especially the antioxidant effect due to their natural radical scavenging potential

Solid phase microextraction applied to honey quality control

The assessment of the botanical origin of unifloral honeys is an important application in food control. The current official methods mainly use pollen analysis. The aim of this paper is to present an SPME analytical approach to the study of honey volatiles. Honey samples (40) obtained from hive sites in different regions of Italy were analysed. The samples had six different botanical origins: citrus (five), chestnut (10), eucalyptus (eight), lime tree (11), thyme (two) and dandelion (four). Melissopalynological analysis was also performed. Identification of volatile compounds was carried out by SPME/GC/MS analysis, and quantitative evaluation was done by SPME/GC/FID analysis for compounds with wellresolved peaks. Using the SPME method, all samples with the same botanical origin gave remarkably similar GC profiles. Some volatile compounds were found only in specific floral source honey samples and thus could be interesting for use as markers

Application of solid phase microextraction to evaluate traces of thymol in honey

The solid phase microextraction technique was tested for thymol evaluation in honey. Thymol can be present in honey as a residue of treatments against Varroa destructor Honey was sampled from apiaries treated with anti-Varroa products whose active ingredient is thymol. Thymol evaluation was done using the internal standard method; benzophenone and carvacrol were tested as internal standards/ the best results were obtained using benzophenone. The application of an alkaline hydrolysis was important for obtaining quantitative recoveries

Application of solid phase mcro extraction to evaluate traces of thymol in honey

The solid phasemicroextraction techniquewas tested for thymol evaluation in honey. Thymol can be present in honey as a residue of treatments against Varroa destructor Honey was sampled from apiaries treated with anti-Varroa products whose active ingredient is thymol. Thymol evaluation was done using the internal standardmethod; benzophenone and carvacrol were tested as internal standards/ the best results were obtained using benzophenone. The application of an alkaline hydrolysis was important for obtaining quantitative recoveries

Characterization of Spanish unifloral honeys by solid phase microextraction and gas chromatography-mass spectrometry

Volatile compounds have been investigated in unifloral honeys of the most popular types in Spain. A total of 21 eucalyptus samples, 35 rosemary samples, 33 heather samples, and 15 citrus samples were collected in the course of 3 years in different Spanish regions. Samples were analyzed by SPME followed by GC-MS. About 83 compounds were identified; the concentrations of 33 of them were selected to be processed by multivariate analysis. Discriminant analysis allowed correct assignment of most samples: 94% citrus, 92% eucalyptus, 84% heather, and 84% rosemary. As pure reference honeys are not available, a two step data analysis is proposed, selecting the samples most clearly classified in discriminant analysis as “reference samples” to be used in multiple regression to estimate the most representative compounds for each honey type and considering the rest of the samples as of mixed origin.Peer reviewe

First report on rare unifloral honey of endemic Moltkia petraea (TRATT.) GRISEB. from Croatia: Detailed chemical screening and antioxidant capacity

Rare Moltkia petraea (Tratt.) Griseb. honey from Croatia was first time characterised. The spectrophotometric assays on CIE L*a*b*Cab*hab° colour coordinates, total phenol content and antioxidant capacity (FRAP, CUPRAC, DPPH• and ABTS•+ assays) determined higher honey values generally close to dark honeys ranges. Headspace solid-phase microextraction (HS-SPME) on two fibres after GC-FID and GC/MS revealed the major compounds 2-phenylacetaldehyde (12.8%; 15.6%), benzaldehyde (11.1%; 10.0%), octane (9.3%; 7.6%), nonane, propan-2-one, pentan-2-one, pentanal and nonanal (4.9%; 14.5%). Ultrasonic solvent extraction (USE) mainly isolated non-specific higher molecular compounds characteristic of the comb environment. Targeted HLPC-DAD analysis of the honey determined higher concentration of phenylalanine (212.08 mg/kg) and lumichrome (16.25 mg/kg) along with tyrosine and kojic acid. The headspace composition (chemical fingerprint) and high concentration of lumichrome can be considered particular for M. petraea honey