Chemometric analysis of bee pollen based on volatile and phenolic compound compositions and antioxidant properties

Abstract

The aim of this study was to determine total amounts of phenolics and flavonoids, radical scavenging activities, and compositions of phenolic and volatile compounds in 14 samples of honeybee pollen collected in the Baltic region. Radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activities and total amounts of phenolics and flavonoids were evaluated using spectrophotometry. Volatiles from the headspace of the samples were analyzed using solid-phase microextraction (SPME) fiber coated with 100-μm polydimethylsiloxane layer, separated, and identified employing GC-mass spectrometry (MS). Forty-two volatiles were identified in the headspace. Nonanal (1.5–20.1 %), dodecane (1.2–-34.6 %), and tridecane (1.4–24.7 %) were found in all samples. Screening of phenolics and flavonoids was performed using high-performance liquid chromatography (HPLC) with electrochemical detection. 2-Hydroxycinnamic acid (43.4–179.9 μg/g), rutin (156.2–955.7 μg/g), and quercetin (24.0–529.8 μg/g) were detected in all tested samples. Total amounts of phenolic compounds and flavonoids varied between 24.1 and 45.5 mg/g, and 6.1 and 11.6 mg/g, respectively, expressed as rutin equivalents. The pollen extracts exhibited radical scavenging activity, which scattered widely in range of 7.1–39.2 mg/g, expressed as rutin equivalents. Radical scavenging activity correlated with the total content of phenolic compounds while correlation coefficient was 0.95. Chemometric evaluation was performed to classify the samples into clusters according to the observed data.