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Caffeine content in kombucha is very much lower than that of normal tea infusion. Though this stimulant plays an important role in kombucha fermentation as it regulates the starter or SCOBY (symbiotic colony of bacteria and yeasts) to produce the cellulose network on broth to accelerate the fermentation process. This research was designed to investigate the aftermath of caffeine and related tea alkaloids in kombucha through preliminary biochemical tests and chromatographic analysis where both the broth (beverage) and SCOBY (the cellulose layer) were taken as individual samples. The beverage clearly revealed negative in all the tests where the SCOBY extract showed richness in alkaloid content. Moreover, GC-MS analysis revealed presence of caffeine (8.7%); guanosine (12.01%), the precursor of caffeine; thymine (4.08%); and some undesirable components which has confirmed that SCOBY has an ability to capture a huge amount of stimulants from tea during fermentation.
Keywords: Caffeine, stimulants, tea, kombucha, SCOBY
10.30954/2277-9396.01.2020.5
ABSTRACT
It is widely accepted that tea leaf and its infusion contain caffeine and other stimulants or alkaloids in significant quantities. Consequently, it is also reported that these stimulants (especially caffeine) are either absent or found in a very low quantity in the probiotic fermented version of tea beverage, called kombucha. According to Malbaša et al. (2006), quantity of these alkaloids gets decreased during fermentation of tea to kombucha. Interestingly, reports have confirmed that caffeine and other compounds can stimulate the ability of Acetobacter xylinum (primary bacterium of SCOBY) to produce a cellulose network, the base of kombucha's microflora (Fontana et al. 1991). According to Greenwalt et al. (2000), methylxanthines and other stimulants can also inhibit the normal switch-off mechanism of cellulose synthase which may also help to accelerate the formation of that cellulose network.
However, there are no report that can clarify the existence of those stimulants in kombucha; whether as by-products of microbial metabolism during fermentation or its involvement into some other microbial pathways inside the SCOBY. This throws a doubt on the fate of caffeine and other alkaloids of tea infusion in its fermented form. So, to find out the aftermath of those components in kombucha, we prepared and carried out preliminary biochemical tests, followed...