Turkish bee pollen: Composition, regional discrimination and polyphenol bioaccessibility

Abstract

Bee pollen has received significant attention due to its high nutritional value and the phenolic composition responsible for its bioactivity. The current research aims to investigate the phenolic composition and antioxidant capacity of 29 monofloral and 21 polyfloral bee pollen samples obtained from different regions of Türkiye by spectroscopic and chromatographic techniques, making regional discrimination based on identified and quantified phenolic compounds and evaluating their bioaccessibility scores by applying a simulated in vitro digestion system. The results demonstrated that the total phenolic and flavonoid contents were 338.15–2857.77 mg GAE/100 g and 84.72–544.20 mg QE/100 g, respectively. HPLC-DAD allowed the identification of a total of 20 phenolic compounds, among which rosmarinic acid (155.38 mg/100 g), naringenin (51.91 mg/100 g), and rutin (34.31 mg/100 g) were in higher amounts than the others. Besides phenolic compound findings, linear discriminant analysis findings revealed a significant difference among regions with an accuracy rate of 70%, and the methyl-3,4,5-trihydroxybenzoate was extracted as the most appropriate discriminant variable. Moreover, although the amounts of some individual phenolic compounds increased or decreased during digestion, both bioaccessibility and antioxidant activity tended to increase. The mean phenolic bioaccessibility score in the intestinal lumen was recorded as 78.93%. Overall, this study focuses on the phenolic composition in bee pollen and provides substantial information on their antioxidant activity and bioaccessibility degree and highlights the importance of in vivo studies on this issue for a better understanding of the bioaccessibility of bioactive compounds in bee pollen.