Microbiological and technological parameters impacting the chemical composition and sensory quality of kombucha

Abstract

Kombucha is a beverage made from sugared tea transformed by yeasts and acetic acid bacteria. Being originally homemade, it has become an industrially produced soft drink whose quality standards are poorly defined and whose production process is still not fully controlled. Based on current knowledge in beverages, links between kombucha's chemical composition and sensorial compounds are drawn. Macromolecules create turbidity, whereas uncharacterized tea pigments derivatives participate in the color. Residual sugars bring sweetness and organic acids produced by acetic acid bacteria form its characteristic sour taste. Acetic acid is also part of its aroma profile, although little data are available on the smell of kombucha. Carbon dioxide, potentially polyphenols, and residual ethanol are involved in the mouthfeel. In this review, after defining the key compounds that shape the characteristic sensory properties of kombucha, the impact of different production parameters is discussed. Water composition is determinant in the extraction of tea compounds along with the tea type and infusion duration and temperature. The type and amount of sweeteners play a role in the sweetness and influences the production kinetics. Similarly, the amount of inoculum and its microbial composition have an effect on the production, but the role of the vessels' geometry and temperature are also essential parameters that can be used to adjust the acidification phase's duration. Despite the amount of research carried out, further investigations of kombucha's sensory characteristics are needed. Such research could lead to a better definition of kombucha's quality and to an improved control over its production process.

Microbial Dynamics between Yeasts and Acetic Acid Bacteria in Kombucha: Impacts on the Chemical Composition of the Beverage

“…Moreover, sucrose appears to play a central role in kombucha symbiosis not only in yeast–bacteria interactions, but also potentially between yeast species. While the AAB composition secondarily impacts the profile in organic acids, the yeast composition in kombucha consortia is crucial for the global microbial dynamics, the chemical composition of the beverage, and the sensory characteristics of the product [ 9 ].…”

“…Glucose and fructose are also used for bacterial cellulose production, leading to the formation of the pellicle, also known as "mother", "tea fungus", or Symbiotic Culture of Yeast and Bacteria ("SCOBY"), since it can be used as inoculum with or instead of liquid culture [4,5,8]. As a result, the beverage has Foods 2020, 9, 963 2 of 25 the profile of a soda with a sweet/sour balance and can also be carbonated naturally if the vessel is left closed after a first phase of biological acidification at ambient temperature [9]. There is no single "culture" or microbial consortium for the production of kombucha, but a multitude of matrix-adapted consortia whose origins are unknown.…”

Isolation, molecular and phylogenetic identification of microorganisms from Kombucha solution and evaluation of their viability using flow cytometery

“…In Figure 5C, the mean color scores of Kombucha beverage in the pre-drying phase at all-time intervals from the beginning of the experiment to the end of the 14th day were not statistically significant. But in the and sensory properties (Tran et al, 2020). Monosaccharides glucose and fructose have a sweetness of 65-75% and 120% (w/w), respectively, compared to sucrose (Villarreal-Soto et al, 2018;Jayabalan et al, 2014).…”

Shedding Light on the Formation and Structure of Kombucha Biofilm Using Two-Photon Fluorescence Microscopy

“…Kombucha is produced by inoculating a sugared tea infusion with a kombucha culture using its broth, the pellicle, or both. The acidification of the broth occurs in an open vessel to ensure access to oxygen by microorganisms, acetic acid bacteria in particular (Tran et al, 2020b), while a new pellicle forms at the surface.…”

“…Kombucha is produced by inoculating a sugared tea infusion with a kombucha culture using its broth, the pellicle, or both. The acidification of the broth occurs in an open vessel to ensure access to oxygen by microorganisms, acetic acid bacteria in particular ( Tran et al, 2020b ), while a new pellicle forms at the surface. Sucrose is converted by yeasts into monosaccharides (glucose and fructose) and ethanol through invertase activity and alcoholic fermentation, respectively.…”