Characterization of Aroma Active Compound Production during Kombucha Fermentation: Towards the Control of Sensory Profiles

Abstract

Since the sensorial profile is the cornerstone for the development of kombucha as a beverage with mass market appeal, advanced analytical tools are needed to gain a better understanding of the kinetics of aromatic compounds during the fermentation process to control the sensory profiles of the drink. The kinetics of volatile organic compounds (VOCs) was determined using stir bar sorptive extraction—gas chromatography—mass spectrometry, and odor-active compounds were considered to estimate consumer perception. A total of 87 VOCs were detected in kombucha during the fermentation stages. The synthesis of mainly phenethyl alcohol and isoamyl alcohol probably by Saccharomyces genus led to ester formation. Moreover, the terpene synthesis occurring at the beginning of fermentation (Δ-3-carene, α-phellandrene, γ-terpinene, m- and p-cymene) could be related to yeast activity as well. Principal component analysis identified classes that allowed the major variability explanation, which are carboxylic acids, alcohols, and terpenes. The aromatic analysis accounted for 17 aroma-active compounds. These changes in the evolution of VOCs led to flavor variations: from citrus-floral-sweet notes (geraniol and linalool domination), and fermentation brought intense citrus-herbal-lavender-bergamot notes (α-farnesene). Finally, sweet-floral-bready-honey notes dominated the kombucha flavor (2-phenylethanol). As this study allowed to estimate kombucha sensory profiles, an insight for the development of new drinks by controlling the fermentation process was suggested. Such a methodology should allow a better control and optimization of their sensory profile, which could in turn lead to greater consumer acceptance.

Unveiling the Aromas and Sensory Evaluation of Hakko Sobacha: A New Functional Non-Dairy Probiotic Fermented Drink

“…As described by Suffys et al (2023) [ 23 ], classes such as alcohols, ketones, aldehydes, and esters are the main metabolites synthesized by the microbiome in kombucha-type fermentation. Indeed, the related metabolic pathways could be similar and adapted to the nutrients present in the infusion.…”

“…Once the solutions were cooled (<35 °C), the inoculum composed of a SCOBY and its liquid starter was added at concentrations of 1% and 10% ( w/w ), respectively. The liquid starter was the result of a previous kombucha fermentation [ 23 ]. The containers were covered with a gauze held by an elastic band (aerobic conditions) and then placed in an oven (IPP55plus; F-Nr.…”

“…The determination of OAV (odor-activity value) was calculated as a function of the considered compound concentration in the sample divided by its ortho-nasal detection perception threshold in water, as referred to in the literature [ 41 , 42 ]. This concept allowed for the study of the contribution of the compounds to the aroma of the drink [ 23 , 43 ].…”

“…The aromatic compounds in kombucha are classified into three categories according to their origin: native from the tea substrate, from the saccharide source, and from the metabolites produced by the MO during fermentation [ 22 ]. Although kombucha presents a complex mixture of VOCs, only a portion of them contribute to the overall aroma and influence the consumer perception [ 23 ].…”

Multi-Strain Probiotics Enhance the Bioactivity of Cascara Kombucha during Microbial Composition-Controlled Fermentation

“…However, the microbial composition of SCOBY varies considerably based on many factors, such as batch variation, geographic location, and tea substrates, making it challenging to establish standardized microbial profiles for kombucha ( Mayser et al, 1995 ). The variability in the microbial community, which is influenced by environmental conditions, fermentation techniques, and SCOBY origin, can result in significant variations in the flavor, aroma, and quality of the final product ( Suffys et al, 2023 ). More-over, the presence of contaminants or undesirable microorganisms may threaten the quality and safety of kombucha ( Villarreal-Soto et al, 2018 ; de Simone, 2019 ).…”