Zea mays L. is one of the biggest cropping systems among the sustainable development agronomy. Pollen from this crop source is unexplored and apiculture can be a good partner adding value to the product and creating new jobs helping to solve some social issues as unemployment. However, food safety is crucial, thus the aim of this study was to explore the flavonoid/phenolic profiles from Z. mays L. pollen as a fingerprint for this plant identification and also to demonstrate how the method of bee pollen samples (honeybee collected pollen) is applied. For this purpose, several sources of Z. mays L. pollen were analyzed, including corn hybrids and genetic modified samples collected at the breeding fields. For this work, samples were taken at several years from 2000 to 2012 and collected from different countries and locations, such as Portugal, Mexico and Brazil. Results showed, for the first time, that the fingerprint (flavonoid/phenolic profile) for Z. mays L. pollen does not change over the time of sampling neither with the region of harvesting. The high performance liquid chromatography-diode array detector (HPLC/DAD) fingerprints of phenolic/flavonoid extract from Z. mays remain unchanged for all samples analyzed from different countries, hybrids and/or genetic modified plants. This is also the first study reporting these phenolic compounds not only in pollen collected directly from hybrid plants, but also in Z. mays bee pollen. The described fingerprinting method is easy, fast and accurate for the characterization of Z. mays L. pollen samples and complete microscopic analysis because it is species-specific.

Abstract:A melissopalynological study carried out on 35 bee pollen samples from Romania (Transylvania) shows predominant species as Taraxacum officinale, Tilia sp., Verbascum sp., Zea mays L., Onobrychis viciifolia Scop., Geranium sanguineum L., Filipendula ulmaria L., Cydonia oblonga L., Calluna vulgaris L. and Brassica sp.. This is the first time for the contribution of total phenolic (TP) and total carotenoid (TC) content to the modified oxygen radical absorbance capacity (ORAC FL ) values in 29 monofloral samples. Hydrophilic ORAC FL (H-ORAC FL ) values ranged between 7.13-10.12 µmol TE/g and 6.94-22.46 µmol TE/g, whereas lipophilic ORAC FL (L-ORAC FL ) values were between 2.19-7.79 µmol TE/g and 1.65-9.96 µmol TE/g, in multifloral and monofloral samples, respectively. It has proved the complex involvement of botanical origins on the antioxidant features with a specific occurrence. Some monofloral samples presented particular high antioxidant potential, such as Salix sp., Taraxacum officinale, Matricaria chamomilla, Cichorium intybus and the poorly studied Cirsium arvense (L.) Scop. and Scilla bifolia L.. New variables, such as soil characteristics, climates together with botanical origins, were introduced in a multivariate analysis of antioxidant data matrix, given a possible important involvement of all of them in affecting, not only the phytochemical composition, but thereafter the antioxidant capacity. All these data could be crucial to a new way of gathering, by beekeepers, depending on the market demand and the purposes for the product that has a potential for further therapeutic bioactivities investigations, and added value in the enrichment of certain products.

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