The aim of the study was to determine nutritional value of bee pollen according to its botanical origin. Pollen is the only natural protein source in bees' nutrition, and due to its nutritional value and functional properties, it is also becoming increasingly recognised and useful in human nutrition, as a bee product. Fifty-two samples of bee pollen collected in 2014-2015, from four Slovenian macroregions, during the three periods of the beekeeping season (spring, summer, late summer/autumn) were obtained. Prior analyses, the samples were microscopically identified. Most of bee pollen samples were of polyfloral origin. On specific bee pastures and with manual selection also a monofloral bee pollen samples from sweet chestnut (Castanea sativa Mill.), rapeseed (Brassica napus var. oleifera DC.), flowering ash (Fraxinus ornus L.), buckwheat (Fagopyrum esculentum Moench), common ivy (Hedera helix L.) and plantain (Plantago spp. L.) were obtained. The contents of water, protein, fat, dietary fibre and ash were determined in accordance with the prescribed AOAC methods. The contents of total and available carbohydrates and the energy value were determined by calculation. The content of individual amino acids was determined by ion-exchange liquid chromatography and the content of elements by X-ray fluorescence spectrometry (XRF). The findings of the research indicate differences between bee pollen samples according to botanical origin in content of protein, fat, insoluble dietary fibre, individual and total amino acids and certain elements. The results were also modelled using multivariate statistical methods and the parameters that are particular for a specific botanical origin of bee pollen were determined, as well for period of collection and geographical origin. Content of non-protein nitrogen in bee pollen was determined and the most appropriate conversion factor for total proteins was estimated. The use of the general conversion factor (6.25) in the calculation provides an overestimated content of proteins in bee pollen, so smaller specific conversion factor of 5.60 is recommended.
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