Spectroscopic Discrimination of Bee Pollen by Composition, Color, and Botanical Origin.

Martina Živčáková,Andriy Synytsya,Roman Bleha,Martina Ježková,Anna Korbářová,Ivan Saloň,Ján Brindza,Tetiana V Shevtsova

doi:10.3390/foods10081682

Martina Živčáková, Andriy Synytsya + Show 6 more

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https://doi.org/10.3390/foods10081682

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Abstract

Bee pollen samples were discriminated using vibrational spectroscopic methods by connecting with botanical sources, composition, and color. SEM and light microscope images of bee pollen loads were obtained and used to assess the botanical origin. Fourier transform (FT) mid- and near-infrared (FT-MIR, FT-NIR), and FT-Raman spectra of bee pollen samples (a set of randomly chosen loads can be defined as an independent sample) were measured and processed by principal component analysis (PCA). The CIE L*a*b* color space parameters were calculated from the image analysis. FT-MIR, FT-NIR, and FT-Raman spectra showed marked sensitivity to bee pollen composition. In addition, FT-Raman spectra indicated plant pigments as chemical markers of botanical origin. Furthermore, the fractionation of bee pollen was also performed, and composition of the fractions was characterized as well. The combination of imaging, spectroscopic, and statistical methods is a potent tool for bee pollen discrimination and thus may evaluate the quality and composition of this bee-keeping product.

Highlights

Bee pollen is a mixture of pollen grains, nectar, and bee excreta
Bee pollen loads assigned to blue tansy were uniform in color
Pollen admixtures in bee pollen loads could be detected by Scanning electron microscopy (SEM) (Figure 1B)

Summary

Introduction

Bee pollen is a mixture of pollen grains, nectar, and bee excreta. Unifloral bee pollen loads are collected by a labor bee from flowers of a single botanical species. In this case, pollen grains have the same morphology and chemical composition; as such bee pollen could be assigned to one of the plant species by microscopic identification of its pollen grains. Different pollen grains are mixed in the loads yielding polyfloral bee pollen. Such pollen loads may show variable properties depending on the ratio between botanical species. Evaluation of such materials is complicated [6,7]

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