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Pollen is characterised for having a low fat content, a relatively high content of dietary fibre and an important amount of minerals and essential amino acids. With regard to bioactive compounds, honeybeecollected pollen exhibits an important source of phytochemical compounds and antioxidant activity. The purpose of this research was to study how the nutritional properties and the stability of the bioactive compounds found in honeybee-collected pollen were affected by the commercial processing and its floral origin. To achieve this goal, pollen pellets of different floral origin were harvested directly from hives and immediately stored at )80°C. Pollen pellets were dried by placing them into hot-air chambers (traditional drying methodology) or by means of freeze-drying. We found a slight influence of floral origin on the nutritional properties of pollen pellets (multifloral pollen had higher contents of fat, carbohydrates, proteins and mineral elements than monofloral-type pollen), whereas the abundance of bioactive compounds was correlated with the origin factor as well as the methodology employed to dry the fresh pollen pellets, especially carotenoid pigments such as lutein (5.73 ± 1.80, 4.93 ± 1.16 and 0.81 ± 0.16 lg of lutein per g of pollen for fresh, lyophilised and hot-air-dried multifloral pollen).Influence of the commercial processing and floral origin D. Domínguez-Valhondo et al.Influence of the commercial processing and floral origin D. Domínguez-Valhondo et al.

A second-order multivariate calibration approach, based on a combination of unfolded-partial least-squares with residual bilinearization (U-PLS/RBL), has been applied to fluorescence excitation-emission matrix data for multicomponent mixtures showing inner filter effects. The employed chemometric algorithm is the most successful one regarding the prediction of analyte concentrations when significant inner filter effects occur, even in the presence of unexpected sample components, which require strict adherence to the second-order advantage. Results for simulated fluorescence excitation-emission data are described, in comparison with the classical approach based on parallel factor analysis and other second-order algorithms, including generalized rank annihilation, bilinear least squares combined with residual bilinearization and multivariate curve resolution-alternating leastsquares. A set of experimental data was also studied, in which calibration was performed with fluorescence excitation-emission matrices for samples containing mixtures of chrysene (the analyte of interest) and benzopyrene (which produced strong inner filter effect across the useful wavelength range). Prediction was made on validation samples with a qualitative composition similar to the calibration set, and also on test samples containing an unexpected component (pyrene). In this latter case, U-PLS/RBL showed a unique success for the analysis of the calibrated component chrysene, achieving the useful second-order advantage.

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