Comparison of phenolic profiles of albino bilberry (Vaccinium myrtillus L.) wines fermented by non-Saccharomyces yeasts

Abstract

The profiles of phenolic compounds in albino bilberry (Vaccinium myrtillus L.) juice and wines fermented with eight different non-Saccharomyces yeasts, including Torulaspora (Tr.) delbrueckii, Issatchenkia (Is.) orientalis, Lachancea (Lc.) thermotolerans, Saccharomycodes (Sd.) ludwigii, Hanseniaspora (Hs.) uvarum, Metschnikowia (Mt.) pulcherrima, Pachysolen (Pc.) tannophilus, and Schizosaccharomyces (Sz.) pombe, were assessed using UHPLC-QTOF-MS and UHPLC-DAD. A total of 40 phenolic compounds, including 20 phenolic acids, 16 flavonols, and 4 flavan-3-ols, were identified and quantified in the albino bilberry products. In unfermented juice, phenolic acids were the most predominant group, accounting for 80.5% of total phenolics. After fermentation, the concentrations of phenolic acids, flavonols, and flavan-3-ols showed significant increases by 21.8%–42.5%, 26.8%–47.2%, and 4.9%–74.5%, respectively. Five new flavonols including myricetin-3-O-glucoside, kaempferol-3-O-galactoside, laricitrin-3-O-galactoside, isorhamnetin-3-O-galactoside, and syringetin aglycone, which were absent in the albino bilberry juice, were formed during fermentation mainly by the metabolism of non-Saccharomyces yeasts. The phenolic compositions of albino bilberry wines depended primarily on the applied yeasts. Most of the non-Saccharomyces yeasts showed positive contributions to the increase of phenolic compounds except for Pc. tannophilus PT70352, which reduced the total phenolic content reflecting the decreases in concentrations of phenolic acids and flavan-3-ols, especially of p-coumaroyl monotropeins, procyanidin B-type dimers, and (−)-epicatechin. The highest levels of phenolic acids and flavan-3-ols were detected in the sample fermented by Hs. uvarum HU26650. The fermentations with Sd. ludwigii SL3447, Tr. delbrueckii TD291, and Mt. pulcherrima MP70321 were characterized by higher concentrations of myricetin-3-O-glucoside and syringetin-3-O-glucoside but lower contents of most phenolic acids.