Antimicrobial and antioxidant activities of natural and fermented bee pollen

Abstract

Fermentation of various food products leads to better nutritional value, improved biological activities, enhanced extraction properties, etc. The impact of artificial solid-state lactic acid fermentation on bee pollen properties has not been fully studied. The aim of this study was to evaluate antibacterial, antifungal and antioxidant activities of natural and pasteurized polyfloral bee pollen after spontaneous fermentation and fermentation with added Lactococcus lactis and Lactobacillus rhamnosus bacteria. Total phenolic content, total flavonoid content and radical scavenging activity increased by 1.27–2.40 times, antibacterial activity against Micrococcus luteus, Staphylococcus aureus and Escherichia coli increased by 1.08–16.9 times and antifungal activity against Penicillium roqueforti increased by 1.96–5.52 times after bee pollen fermentation. Chemometric analysis, including a similarity measure (based on Euclidean distance) estimation and self-organizing maps, were used to determine the impact of different fermentations and pasteurization on bee pollen's antioxidant and antimicrobial properties. The analysis showed that the natural microflora of the bee pollen contributes to the fermentation process together with the added bacteria, therefore pasteurized bee pollen showed significantly lower antimicrobial and antioxidant activities after fermentation than fermented natural bee pollen. Overall, the fermentation had a positive effect on bee pollen biological activities, the improvements being dependent on the botanical origin of the pollen and fermentation type (spontaneous or with added bacteria).