Kinetics of volatile organic compounds during papaya juice fermentation by three commercial wine yeasts

Abstract

Purpose: The purpose of this paper is to assess the potential of papaya juice fermentation and to evaluate the kinetic changes of volatile organic compounds (VOCs) produced during fermentation by three commercial wine yeasts. Design/methodology/approach: Laboratory-scale fermentations were carried out in papaya juice using three commercial wine yeasts Saccharomyces cerevisiae var. bayanus strains EC-1118 and R2, and S. cerevisiae MERIT.ferm. Brix, pH, optical density and yeast cell count were determined during fermentation. VOCs were analysed by headspace-solid phase microextraction with gas chromatography-mass spectrometry-flame ionization detector (HS-SPME-GC-MS/FID). Findings: During fermentation, the three wine yeasts grew actively and showed similar growth patterns. Changes in Brix and pH were similar among the three yeasts. A range of VOCs were produced during fermentation including fatty acids, alcohols, acetaldehyde, esters and acetoin. Esters were the most abundant VOCs produced. Some VOCs indigenous to the papaya juice such as benzaldehyde, β-damascenone and benzyl isothiocyanate were consumed during fermentation. Some VOCs increased initially, and then decreased during fermentation. Overall, the profiles of VOC changes during fermentation were similar among the three yeasts with some differences observed. Originality/value: The paper suggests that papaya fermentation with S. cerevisiae yeasts are likely to result in papaya wine with similar flavours. New approaches are required to produce papaya wine with distinct flavours and to enable differentiation of papaya wines by exploiting non-Saccharomyces yeasts in conjunction with Saccharomyces yeasts and/or by adding selected nitrogen sources. © Emerald Group Publishing Limited.