Page 46 - FoodFocusThailand No.215 FEBRUARY 2024

SMART PRODUCTION

6. Ferment at 20-30 °C or room temperature in a dark the risk of contamination from molds. The fermentation
place. During fermentation, the microorganisms multiply and temperature for kombucha is commonly maintained between
form a cellulose layer or SCOBY within 2-3 days. This layer 20-30 °C. An increase in fermentation temperature leads to
will cover the entire surface of the liquid within 10-14 days, a faster fermentation rate, observable through a rapid
depending on the source and composition of the SCOBY decrease in pH and the formation of SCOBY on the surface.
microorganisms. At this point, the pH value of the tea will However, the fermentation temperature of 25-30 °C promotes
decrease to around 2.0. the robust growth of acetic acid bacteria, while yeasts growth
7. Separate the SCOBY in the final stage of fermentation, relatively limited. This results in a kombucha with higher
and then store it in a bottle that has been sterilized and kept acidity and lower alcohol content.
at a low temperature (4 °C) to avoid contamination from other The previous study showed that fermenting kombucha
microorganisms. This helps extend the shelf life of the at a temperature of 30 °C promoted the growth of
product. The resulting kombucha will have a low alcohol Gluconobacter bacteria, leading to an increased production
content (0.5-2.5% alcohol by volume), a slightly acidic taste, of gluconic acid and glucuronic acid. On the other hand,
and a mild effervescence due to carbon dioxide gas. fermenting at 25 °C helped maintain the stability of flavonoid
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compounds and enhances the enzyme inhibitory properties,
The Kinetics of Kombucha Fermentation such as alpha-amylase. The alpha-amylase enzyme breaks
The fermentation process of kombucha occurs in an oxygen- down carbohydrates and is associated with diabetes. 6
rich environment and relies on the activities of various groups However, fermenting at temperatures lower than 20 °C may
of microorganisms, including yeasts and bacteria within the result in a stuck or sluggish fermentation and the condition
Acetobacteraceae family which are known for producing might be vulnerable to microbial deterioration. Conversely,
acetic acid or vinegar. In the early stages of kombucha too high fermentation temperatures can produce ethyl alcohol
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fermentation, yeast plays a crucial role utilizing the sugars and highly concentrated acetic acid, affecting the aroma and
present in the initial ingredients as an energy source. It taste of the final product, along with accelerating oxidation
converts disaccharides (such as sucrose) into reactions of polyphenol compounds.
monosaccharides (glucose and fructose), resulting in the Controlling the temperature in the kombucha fermentation
production of ethanol and carbon dioxide. As the fermentation process is crucial to ensure efficient production, production
progresses, the group of Acetobacteraceae family capable of high-quality kombucha, batch-to-batch reproducibility and
of oxidizing ethanol and monosaccharides becomes safe production.
predominant in the later stages of fermentation. Acetic acid
bacteria further convert sugars into acetic acid and other
organic acids and produce cellulose fibers. A floating jelly-like
layer covering the surface of kombucha consists of Symbiotic
Colony of Bacteria and Yeast (SCOBY). The microbial More Information Service Info C006
consortium in SCOBY includes Zygosaccharomyces
Saccharomyces, Schizosaccharomyces (yeasts), lactic acid
bacteria and Gluconobacter and Acetobacter (bacteria). The
Microbial compositions in SCOBY can vary depending on เอกสารอ้างอิง / References
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the ingredients and fermentation conditions. Notably, the 1 Malbaša, R., LonCar, E., DjuriC, M., & DošenoviC, I. (2008). Effect
types of microorganisms present in SCOBY are one of crucial of sucrose concentration on the products of Kombucha fermentation
factors determining the aroma, taste, and health properties on molasses. Food Chemistry, 108(3), 926-932. https://doi.org/https://
of the kombucha. 4 doi.org/10.1016/j.foodchem.2007.11.069
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Kitwetcharoen, H., Phung, L. T., Klanrit, P., Thanonkeo, S., Tippayawat,
P., Yamada, M., & Thanonkeo, P. (2023). Kombucha Healthy Drink-
Temperature: Key Factor Influencing Kombucha Recent Advances in Production, Chemical Composition and Health
Fermentation Benefits. Fermentation, 9(1), 48. https://www.mdpi.com/2311-
Controlling the temperature during fermentation is crucial for 5637/9/1/48
De Filippis, F., Troise, A. D., Vitaglione, P., & Ercolini, D. (2018).
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the efficiency and quality of the kombucha. Microorganisms Different temperatures select distinctive acetic acid bacteria species
in kombucha varies greatly with fermentation temperature. and promotes organic acids production during Kombucha tea
For instance, the optimal temperature for the growth of acetic fermentation. Food Microbiology, 73, 11-16. https://doi.org/https://doi.
acid bacteria is 25 to 30 °C, whereas yeasts, especially non- org/10.1016/j.fm.2018.01.008
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Dufresne, C., & Farnworth, E. (2000). Tea, Kombucha, and health: a
Saccharomyces yeasts, has lower optimum temperature. 5 review. Food Research International, 33(6), 409-421. https://doi.org/
Therefore, different fermentation temperatures affect https://doi.org/10.1016/S0963-9969(00)00067-3
significantly the growth rate, proportions, and quantities of 5 Liszkowska, W., & Berlowska, J. (2021). Yeast Fermentation at Low
microorganisms in each strain. Additionally, it affects the Temperatures: Adaptation to Changing Environmental Conditions and
enzyme activity and the products resulting from the metabolic Formation of Volatile Compounds. Molecules, 26(4). https://doi.
processes of microorganisms. These factors collectively org/10.3390/molecules26041035
Aung, T., & Eun, J.-B. (2021). Production and characterization of a
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influence the quality and consistency of kombucha. novel beverage from laver (Porphyra dentata) through fermentation
Temperature also plays a vital role in the safety of kombucha, with kombucha consortium. Food Chemistry, 350, 129274. https://doi.
as inappropriate fermentation temperatures may increase org/https://doi.org/10.1016/j.foodchem.2021.129274
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