The volatile profiles of a rare apple (Malus domestica Borkh.) honey: shikimic pathway derivatives, terpenes and others

The volatile profiles of rare Malus domestica Borkh. honey were investigated for the first time. Two representative samples from Poland (sample I) and Spain (sample II) were selected by pollen analysis (44 –45% of Malus spp. pollen) and investigated by GC/FID/MS after headspace solid-phase microextraction (HS-SPME) and ultrasonic solvent extraction (USE). The apple honey is characterized by high percentage of shikimic acid-pathway derivatives, as well as terpenes, norisoprenoids, and some other compounds such as coumaran and methyl 1H-indole-3-acetate. The main compounds of the honey headspace were (sample I; sample II): benzaldehyde (9.4%; 32.1%), benzyl alcohol (0.3%; 14.4%), hotrienol (26.0%, 6.2%), and lilac aldehyde isomers (26.3%; 1.7%), but only Spanish sample contained car-2-en-4-one (10.2%). CH2Cl2 and pentane/Et2O 1:2 (v/v) were used for USE. The most relevant compounds identified in the extracts were: benzaldehyde (0.9–3.9%), benzoic acid (2.0–11.2%), terpendiol I (0.3–7.4%), coumaran (0.0–2.8%), 2-phenylacetic acid (2.0–26.4%), methyl syringate (3.9–13.1%), vomifoliol (5.0 –31.8%), and methyl 1H-indole-3-acetate (1.9–10.2%). Apple honey contained also benzyl alcohol, 2-phenylethanol, (E)-cinnamaldehyde, (E)-cinnamyl alcohol, eugenol, vanillin, and linalool that have been found previously in apple flowers, thus disclosing similarity of both volatile profiles

Activity of Polish unifloral honeys against pathogenic bacteria and its correlation with colour, phenolic content, antioxidant capacity and other parameters

The use of honey as an antimicrobial agent gains importance due to often ineffectiveness of conventional treatment. However, activity of honey depends mainly on its botanical and geographical origin. To date, antimicrobial potential of Polish honeys has not yet been entirely investigated. In this study, 37 unifloral samples of 14 honey types (including rare varieties) from Poland were analysed and compared with manuka honey. The most active were cornflower, thyme and buckwheat honeys. Their MICs ranged from 3·12 to 25·00%, (depending on tested micro-organism) and often were lower than for manuka honey. Additionally, colour, antioxidant activity, total phenols, pH and conductivity were assessed and significant correlations (P < 0·05) of MICs with several parameters were found. The most active were darker honeys, with strong yellow colour component, rich in phenolics, with high conductivity and water content. The honey antibacterial properties depended mainly on peroxide mechanism and were vulnerable to excessive heating, but quite stable during storage in cold. A number of honey samples showed potential as effective antimicrobial agents. The observed correlations of MICs and physical-chemical parameters help to understand better the factors impacting the antibacterial activit

Screening of Coffea spp. honey by different methodologies: theobromine and caffeine as chemical markers

Coffea spp. honey was screened by UV/VIS, HS-SPME/GC-MS/FID, USE/GC-MS/FID and HPLC-DAD. The direct HPLC-DAD methodology overcame the major limitations of the other methods used. The obtained results constitute a breakthrough since dominant xanthine derivatives were found (theobromine and caffeine with HPLC-DAD and caffeine by USE/GC-MS/FID). Phenylacetaldehyde was the major headspace compound

Phytochemical and physical-chemical analysis of Polish willow (Salix spp.) honey: identification of the marker compounds

The case study of Polish Salix spp. honey was compared with published data on willow honey from other regions. GC-FID/MS (after HS-SPME and ultrasonic solvent extraction) and targeted HPLC-DAD were applied. Phenolic content, FRAP/DPPH assays and the colour coordinates were determined spectrophotometrically. Beside ubiquitous linalool derivatives, borneol (up to 10.9%), bicyclic monoterpenes with pinane skeleton (pinocarvone up to 10.6%, myrtenal up to 4.8% and verbenone up to 3.4%) and trans-bdamascenone (up to 13.0%) dominated in the headspace. The main compounds of the extractives were vomifoliol (up to 39.6%) and methyl syringate (up to 16.5%) along with not common 4-hydroxy-3-(1-methylethyl)benzaldehyde (up to 11.1%). Abscisic acid (ABA) was found (up to 53.7 mg/kg) with the isomeric ratio (Z,E)-ABA:(E,E)-ABA = 1:2. The honey exhibited low antioxidant potential with pale yellow colour. The composition of Polish willow honey is similar to Mediterranean willow honeys with several relevant differences

Comprehensive study of Mediterranean (Croatian) Propolis peculiarity: headspace, volatiles, anti-Varroa-treatment residue, phenolics, and antioxidant properties

Eight propolis samples from Croatia were analyzed in detail, to study the headspace, volatiles, anti-Varroa-treatment residue, phenolics, and antioxidant properties. The samples exhibited high qualitative/quantitative variability of the chemical profiles, total phenolic content (1,589.3-14,398.3 mg GAE (gallic acid equivalent)/l EtOH extract), and antioxidant activity (11.1-133.5 mmol Fe2+/l extract and 6.2-65.3 mmol TEAC (Trolox® equivalent antioxidant capacity)/l extract). The main phenolics quantified by HPLC-DAD at 280 and 360 nm were vanillin, p-coumaric acid, ferulic acid, chrysin, galangin, and caffeic acid phenethyl ester. The major compounds identified by headspace solid-phase microextraction (HS-SPME), simultaneous distillation extraction (SDE), and subsequent GC-FID and GC/MS analyses were α-eudesmol (up to 19.9%), β-eudesmol (up to 12.6%), γ-eudesmol (up to 10.5%), benzyl benzoate (up to 28.5%), and 4-vinyl-2-methoxyphenol (up to 18.1%). Vanillin was determined as minor constituent by SDE/GC-FID/MS and HPLC-DAD. The identified acaricide residue thymol was ca. three times more abundant by HS-SPME/GC-FID/MS than by SDE/GC-FID/MS and was not detected by HPLC-DA

Cornflower (Centaurea cyanus L.) honey quality parameters: chromatographic fingerprints, chemical biomarkers, antioxidant capacity and others

The samples of cornflower (Centaurea cyanus L.) honey from Poland were subjected to ultrasonic solvent extraction applying the mixture of pentane and diethyl ether 1:2 v/v (solvent A) as well as dichloromethane (solvent B). The major compounds of the extracts (analysed by GC–MS/GC–FID) were C13 and C9 norisoprenoids. Among them, (E)-3-oxo-retro-a-ionol (2.4–23.9% (solvent A); 3.9–14.4% (solvent B)) and (Z)-3-oxo-retro-a-ionol (3.7–29.9% (solvent A); 8.4–20.4% (solvent B)) were found to be useful as chemical biomarkers of this honey. Other abundant compounds were: methyl syringate (0.0–31.4% (solvent A); 0.0–25.4% (solvent B)) and 3-hydroxy-4-phenylbutan-2-one (1.6–15.8% (solvent A); 5.1–15.1% (solvent B)). HPLC–DAD analysis of the samples revealed lumichrome (4.7–10.0 mg/kg), riboflavin (1.9–2.7 mg/kg) and phenyllactic acid (112.1–250.5 mg/kg) as typical compounds for this honey type. Antioxidant and antiradical properties as well as total phenolic content of the samples were found to be rather moderate by FRAP (ferric reducing antioxidant power), DPPH (1,1-diphenyl-2-picrylhydrazyl radical) and Folin–Ciocalteu assays, respectively. Additionally, CIE L⁄a⁄b⁄C⁄h chromatic coordinates were evaluated. Colour attributes of cornflower honey were characterised by elevated values of L* and particularly high values of b* and h coordinates, which correspond to medium bright honey with intense yellow colour

Antioxidant activity, color characteristics, total phenol content and general HPLC fingerprints of six Polish unifloral honey types

Total phenolic content, antioxidant activity (two assays: 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and ferric reducing antioxidant power (FRAP)), and color coordinates (CIE (Commission Internationale de l’Eclairage) L*a*b*) for six Polish unifloral honeys (black locust, rapeseed, lime, goldenrod, heather and buckwheat) were assessed for several batches of the same honey type and statistically evaluated. Total phenolic content (121.6e1173.8 mg GAE/kg) was similar to the values previously reported for other European honeys and it was also correlated with the color parameters as well as antioxidant activity. The honeys’ color ranged from pale yellow to dark amber. Dark buckwheat honey with much higher phenolic content (1113.0 mg GAE/kg) exhibited higher antioxidant activity (5.7 mmol Fe2þ/kg and 1.2 mmol TEAC/kg). CIE L*a*b* color coordinates can be helpful for identifying and distinguishing between several honey types, such as heather and buckwheat, but almost no differences were found among very light honeys (rapeseed, goldenrod, black locust and lime). High-performance liquid chromatographic (HPLC) analysis revealed general characteristic fingerprints of Polish unifloral honeys with significant differences among the samples of other honey types

Color evaluation of seventeen European unifloral honey types by means of spectrophotometrically determined CIE L*C*abh°ab chromaticity coordinates

CIE (Commission Internationale de l’Eclairage) LCabh ab color coordinates for 305 samples of 17 unifloral honeys types (asphodel, buckwheat, black locust, sweet chestnut, citrus, eucalyptus, Garland thorn, honeydew, heather, lime, mint, rapeseed, sage, strawberry tree, sulla flower, savory and thistle) from different geographic locations in Europe were spectrophotometrically assessed and statistically evaluated. Preliminary separation of unifloral honeys was obtained by means of L*-Cab color coordination correlation. Hierarchical Cluster Analysis (HCA) revealed an expected segregation of the honeys types according to their chromatic characteristics. Principal Component Analysis (PCA) allowed to obtain a more defined distinction of the 17 unifloral honey types, particularly when using 3D graphics. CIE LC abh ab color coordinates were useful for the identification of several honey types. The proposed method represents a simple and efficient procedure that can be used as a basis for the authentication of unifloral honeys worldwide