Volatilome and Bioaccessible Phenolics Profiles in Lab-Scale Fermented Bee Pollen.

Raffaella Di Cagno,Pasquale Filannino,Marco Gobbetti,Ali Zein Alabiden Tlais,Vincenzo Cantatore,Giuseppe Gambacorta

doi:10.3390/foods10020286

Abstract

Bee-collected pollen (BCP) is currently receiving increasing attention as a dietary supplement for humans. In order to increase the accessibility of nutrients for intestinal absorption, several biotechnological solutions have been proposed for BCP processing, with fermentation as one of the most attractive. The present study used an integrated metabolomic approach to investigate how the use of starter cultures may affect the volatilome and the profile of bioaccessible phenolics of fermented BCP. BCP fermented with selected microbial starters (Started-BCP) was compared to spontaneously fermented BCP (Unstarted-BCP) and to unprocessed raw BCP (Raw-BCP). Fermentation significantly increased the amount of volatile compounds (VOC) in both Unstarted- and Started-BCP, as well as modifying the relative proportions among the chemical groups. Volatile free fatty acids were the predominant VOC in Unstarted-BCP. Started-BCP was differentiated by the highest levels of esters and alcohols, although volatile free fatty acids were always prevailing. The profile of the VOC was dependent on the type of fermentation, which was attributable to the selected Apilactobacillus kunkeei and Hanseniaspora uvarum strains used as starters, or to the variety of yeasts and bacteria naturally associated to the BCP. Started-BCP and, to a lesser extent, Unstarted-BCP resulted in increased bioaccessible phenolics, which included microbial derivatives of phenolic acids metabolism.

Highlights

Bee-collected pollen (BCP) is currently receiving increasing attention due to its remarkable levels of valuable nutrients and bioactive compounds [1,2,3,4]
Total volatile compounds (VOC) in raw BCP (Raw-BCP) were estimated at 17,751 ± 628 ppb, with aldehydes as predominant group (30% of the total VOC), followed by alcohols (21%), ketones (16%), and volatile free fatty acids (VFFA) (12%)
Since fermentation was previously shown to improve the digestibility of BCP [13], we investigated how controlled or spontaneous fermentation may affect the profile of bioaccessible phenolic

Summary

Introduction

Bee-collected pollen (BCP) is currently receiving increasing attention due to its remarkable levels of valuable nutrients and bioactive compounds [1,2,3,4]. BCP needs to be processed before human consumption, in order to impair the pollen wall and to increase the accessibility of nutrients for intestinal absorption. The conversion of BCP to bee bread results from several biochemical changes, including the modification of the intine-exine complex, which in turn leads to an increased accessibility of nutrients and bioactive compounds [3,4]. The occurrence of yeasts, molds, and other aerobic and anaerobic bacteria has been described Many of these microorganisms are metabolically relevant during bee bread maturation, while some of them are contaminants [12,13,14,15]. Due to the prominent role of this complex microbial consortium, the emulation of bee bread fermentation through a controlled lab-scale process is difficult

Methods

Results

Conclusion