Impact of Pure, Co-, and Sequential Fermentations with Hanseniaspora sp. and Saccharomyces cerevisiae on the Volatile Compounds of Ciders

Abstract

Pure, co-, and sequential fermentations of Hanseniaspora uvarum, H. guilliermondii, and Saccharomyces cerevisiae strains were evaluated to improve the aromatic quality of ciders. In sequential fermentations, Hanseniaspora strains were used as starter, followed by S. cerevisiae inoculation succeeding one, two, and three days of fermentation. Kinetics, physicochemical parameters, and volatile compounds were assessed during 10 days of fermentation. The headspace technique was used to capture the volatile compounds from the ciders obtained in each experiment and analyzed by gas chromatography. Fermentations with pure strains of Hansenisaspora sp. showed a high population (>1010 CFU/mL) but had a low fermentation rate (2.3–3.8 CO2 g/L/d), low consumption of amino acids (20–40 mg/L) with a high residual content, high sugar consumption (80–90 g/L), and low alcohol content (<2.0% v/v). The H. uvarum strain produced a notably high ester content (245 mg/L). In the co-fermentations, H. guilliermondii with S. cerevisiae highlighted a significant production of higher alcohols, similar to that produced by S. cerevisiae alone (152–165 mg/L). In general, the maximum fermentation rate of the sequential inoculations was lower than co-fermentations but showed low residual nitrogen content (<69 mg/L) and good conversion of sugars into ethanol (4.3–5.7% v/v). The highest concentrations of volatile compounds were observed in treatments involving the two non-conventional strains: H. uvarum with S. cerevisiae inoculation after three days (564 mg/L) and H. guilliermondii after just one day (531 mg/L) of fermentation. These differences stemmed from the metabolic activity of the strains. H. uvarum was influenced by the presence of Saccharomyces, whereas H. guilliermondii did not exhibit this effect. Thus, a pure H. uvarum inoculum has the potential to produce a demi-sec cider with low alcohol content and high content of esters, contributing to a fruity aroma. In addition, ciders with sequential inoculation were the most promising for dry cider processing concerning fermentation parameters and bioaroma enrichment.