Saša Prđun

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.

Colony development of two Carniolan genotypes (Apis mellifera carnica) in relation to environment

Summary The objective of this study was to compare the colony development cycle (unsealed and sealed worker brood, drone brood, pollen and colony strength) of two Apis mellifera carnica subpopulations in two distinct environments (alpine and continental). At each test location were two sub groups of 12 colonies headed by naturally mated sister queens from either the Institute of Apiculture Lunz am See, Austria (AT) or from the Faculty of Agriculture University of Zagreb, Croatia (HR). Colony development was monitored every 14 days. The HR genotype, adapted to a continental climate, had faster spring brood development in both environments. During spring and early summer the AT genotype maintained the number of sealed brood cells at a constant level in the more favourable conditions, although the amount of unsealed brood reached its maximum in early June. The environment influenced colony development, food stores and colony strength. Interaction between genotype and environment did not affect the number of unsealed brood cells, but the difference was statistically significant for the number of sealed brood cells. The study indicated the presence of a number of genotype and environment interactions between the two honey bee genotypes and their colony traits.

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).

Variation of wild boar reproductive performance in different habitat types : implications for management

The aim of this study was analyze reproductive performance of wild boar in different habitat over a 7-year period (2006–2012). A total of 468 pregnant females and 2.819 fetuses were analyzed, the mean number of fetuses was 6.02 (median = 6) per animal (4.62 per juvenile, 6.39 per yearling and 6.77 per adult). In litters, male-biased fetuses occurred significantly more often than female, the overall fetal sex ratio is 1: 0.86. Positive reproductive traits increased up to 90 kg of live body weight and then decreased. The reproductive parameters observed in our study reflect a relatively high reproductive capacity compared to the populations in southern and northern Europe, but are comparable with some populations in central Europe. Concerning habitat conditions, it is obvious that they influence the reproductive performance of females, and therefore must be included in management plans.

BODY MEASUREMENT OF WOODCOCK (SCOLOPAX RUSTICOLA L.) IN CENTRAL CROATIA

Woodcock (Scolopax rusticola, Linnaeus 1758) is one of the most prevailing types of the Scalopax species, and presents the important species in the entire biocenosis. Although today the woodcock population is considered stable worldwide, the newest research in biology and concrete guidelines in hunting management are necessary for the future. The reason to start this research was simply this unsufficiently researched population of woodcock which has its habitat in our area. According to the data available from the literature morphological values gathered match.