Polyphenol profile of buckwheat honey, nectar and pollen

Abstract

A focus of research in recent years is the comparison of honey as the final product of bees with pollen and nectar of the plant from which the honey originates, as the main food source for bees. Buckwheat honey is recognized as a nutritionally valuable product, which provides a scientifically proven health benefit and is confirmed as a functional food. The quality of this type of honey is attributed to high levels of phytochemicals in buckwheat. The purpose of this study was the examination of similarity between buckwheat honey and buckwheat nectar and pollen, as well as simultaneous investigation of their chemical profiles and the origin of the honey. The phenolic profile of buckwheat pollen showed a lower number of flavonoids and phenolic acids than those of nectar and honey samples, but confirmed the presence of the most characteristic polyphenols derived from the buckwheat plant. The notable difference was found to be the presence of (epi)catechin units, its galloylated derivatives and procyanidin dimers, which were not present in honey. Honey polyphenols displayed a pronounced correlation with those of nectar, but not with those of pollen. Finally, by comparing the polyphenolic profiles of honey, nectar and pollen sharing the same geographical origin, new data could be provided for a potential assessment of the botanical origin of buckwheat honey.

Distribution of polyphenolic and sugar compounds in different buckwheat plant parts

“…2), neither in pollen and in nectar. 31 The gallic acid was reported to be present in buckwheat sample extracts, 17,24,25,39 as we noted in this study (Fig. 2).…”

“…In general, the presence of phenolic acids in analysed buckwheat sample extracts was similar to the results reported by other authors. 23,25,31,39 Several phenolic acids such as protocatechuic acid (no 6), p-hydroxybenzoic acid (no 13) and ferulic acid (no 26), already reported as present in buckwheat, 39 were also found as common for all buckwheat sample extracts in this study (Fig. 2).…”

“…The ferulic acid was also found in buckwheat honey from Poland, previously analysed, but not in buckwheat nectar, pollen and Serbian honey sample. 31 The intensity of the ferulic acid was the most prominent in the buckwheat ower, followed by leaf, and then stem and grain (Fig. 2).…”

“…† The compounds were conrmed using the standards and the previously published MS data. 27,31,35,[40][41][42][43][44][45][46][47][48][49][50][51] The frequency of phenolic compounds in the buckwheat sample extracts is presented as colour scale, which dened the intensity of the obtained peak area of one compound per sample (Fig. 2).…”

“…2 Furthermore, a notable number of the identied polyphenols in 'Novosadska' buckwheat nectar showed a good correlation with a phenolic prole of buckwheat honey, as well as with buckwheat pollen. 31 In order to expand the investigation related to 'Novosadska' buckwheat, the different parts of this plant were analysed. Therefore, the phenolic prole and the antioxidant capacity of 'Novosadska' buckwheat leaf, stem, ower and grain were analysed, and compared with those in the corresponding buckwheat pollen, nectar and honey, previously published.…”