Lidija Svečnjak

Traceability of Satsuma mandarin (Citrus unshiu Marc.) honey through nectar/honey-sac/honey pathways of the headspace, volatiles, and semi-volatiles: Chemical markers

Headspace solid-phase microextraction (HS-SPME) and ultrasonic solvent extraction (USE), followed by GC-MS/FID, were applied for monitoring the nectar (NE)/honey-sac (HoS)/honey (HO) pathways of the headspace, volatiles, and semi-volatiles. The major NE (4 varieties of Citrus unshiu) headspace compounds were linalool, α-terpineol, 1H-indole, methyl anthranilate, and phenylacetonitrile. Corresponding extracts contained, among others, 1H-indole, methyl anthranilate, 1,3-dihydro-2H-indol-2-one and caffeine. The major HoS headspace compounds were linalool, α-terpineol, 1,8-cineole, 1H-indole, methyl anthranilate, and cis-jasmone. Characteristic compounds from HoS extract were caffeine, 1H-indole, 1,3-dihydro-2H-indol-2-one, methyl anthranilate, and phenylacetonitrile. However, HO headspace composition was significantly different in comparison to NE and HoS with respect to phenylacetaldehyde and linalool derivatives abundance that appeared as the consequence of the hive conditions and the bee enzyme activity. C. unshiu honey traceability is determined by chemical markers: phenylacetaldehyde, phenylacetonitrile, linalool and its derivatives, as well as 1H-indole, 1,3-dihydro-2H-indol-2-one, and caffeine.

An approach for routine analytical detection of beeswax adulteration using FTIR-ATR spectroscopy

Abstract Although beeswax adulteration represents one of the main beeswax quality issues, there are still no internationally standardised analytical methods for routine quality control. The objective of this study was to establish an analytical procedure suitable for routine detection of beeswax adulteration using FTIR-ATR spectroscopy. For the purpose of this study, reference IR spectra of virgin beeswax, paraffin, and their mixtures containing different proportions of paraffin (5 - 95%), were obtained. Mixtures were used for the establishment of calibration curves. To determine the prediction strength of IR spectral data for the share of paraffin in mixtures, the Partial Least Squares Regression method was used. The same procedure was conducted on beeswax-beef tallow mixtures. The model was validated using comb foundation samples of an unknown chemical background which had been collected from the international market (n = 56). Selected physico-chemical parameters were determined for comparison purposes. Results revealed a strong predictive power (R2 = 0.999) of IR spectra for the paraffin and beef tallow share in beeswax. The results also revealed that the majority of the analysed samples (89%) were adulterated with paraffin; only 6 out of 56 (11%) samples were identified as virgin beeswax, 28% of the samples exhibited a higher level of paraffin adulteration (>46% of paraffin), while the majority of the analysed samples (50%) were found to be adulterated with 5 - 20% of paraffin. These results indicate an urgent need for routine beeswax authenticity control. In this study, we demonstrated that the analytical approach defining the standard curves for particular adulteration levels in beeswax, based on chemometric modelling of specific IR spectral region indicative for adulteration, enables reliable determination of the adulterant proportions in beeswax.

Characterization of Satsuma mandarin (Citrus unshiu Marc.) nectar-to-honey transformation pathway using FTIR-ATR spectroscopy

Samples of Satsuma mandarin (Citrus unshiu Marc.) nectar, honey sac content and honey were analyzed by FTIR-ATR spectroscopy and reference methods. The spectral analysis allowed detection of the major chemical constituents in C. unshiu nectar-to-honey transformation pathway thus providing information on the intensity and location of the compositional changes occurring during this process. The preliminary results showed that in average more than one-third of sugar-related nectar-to-honey conversion takes place directly in the honey sac; the average sugar content (w/w) was 17.93% (nectar), 47.03% (honey sac) and 79.63% (honey). FTIR-ATR results showed great spectral similarity of analyzed honey samples and small degree variations in both sugar and water content in nectar samples. The spectral data revealed distinctive differences in the chemical composition of individual honey sac contents with the most intensive and complex absorption envelope in the spectral region between 1175 and 950cm-1 (glucose, fructose and sucrose absorption bands).

Zeolite clinoptilolite as a dietary supplement and remedy for honeybee (Apis mellifera L.) colonies

Control of the nosema disease poses a major challenge, and therefore, treatment of this serious para - sitic disease using natural preparations could be of great benefit. The aim of this study was to test the performance of zeolite clinoptilolite as a curative measure against honeybee colonies ( Apis mellifera L.) naturally infected by Nosema ceranae. The histopathological structure, and the content and distribution of mucosubstances and his - tochemical activity of aminopeptidase and non-specific esterase in the midgut mucosa of honeybees originating from colonies fed sugar syrup supplemented with zeolite minerals was studied. A decline in the number of spores in honeybees fed with zeolite clinoliptolite was observed on the first sampling day (Day 10; 53.25 15.15 million spores/bee), though a statistically lower number of spores in comparison to the control was confirmed on Day 20 (41.08 ± 9.4 million spores/bee), Day 30 (28.42 ± 7.79 million spores/bee) and Day 40 (24 ± 6.25 million spores/bee). The possibility of using natural zeolites as a dietary supplement for honeybee colonies as a preventative measure and for the reduction of the deleterious effects of nosemosis is discussed.

Rhamnus frangula Honey: Screening of Volatile Organic Compounds and Their Composition After Short-Term Heating

There is no report on the chemical composition of alder buckthorn (Rhamnus frangula L.) honey and therefore volatile organic compounds (VOCs) were investigated for the first time as well as their composition after short-term heating. The electrical conductivity of the samples was 0.90 - 0.98 mScm-1 (specificity of alder buckthorn honey), and pH values were 4.00 - 4.33. The melissopalynological analysis revealed R. frangula L. as dominant plant species (52-93%) in all samples. Accompanying minor plant species were also determined (Castanea sativa L., Centaurea jacea L., Lotus corniculatus L., Prunus spp., Salix spp., Apiaceae, Asteraceae, Acer spp. and Cornus sanguinea L.). The VOCs from R. frangula L. honey were isolated by headspace solid-phase microextraction (HS-SPME) and ultrasonic solvent extraction (USE) and analysed by GC-FID and GC-MS. To investigate the influence of short-term heating, selected sample was heated 3h at 100 oC with and without H2O addition. The most representative chemical profile of R. frangula L. honey is obtained by HS-SPME containing benzaldehyde, hotrienol and 4-ketoisophorone. USE contributed to the honey characterization, mainly by vomifoliol identification. The majority of compounds found in USE were higher aliphatic alcohols. The influence of short-term heating to R. frangula L. honey is strongly dependent on H2O addition. Namely, more artefacts (furan derivatives, particularly 5-hydroxymethylfurfural) were formed during heating of the honey dissolved in H2O in comparison with direct honey heating.