Chiang Mai University researchers compared green, oolong and black tea kombuchas, then formulated the stronger in-vitro antioxidant green-tea concentrate as a nanoemulsion. Mean size was 110.03 nm, encapsulation efficiency 91.66%, and physical nanoscale stability persisted for six months at 4°C, with biphasic release and uptake by three cell lines. This supports a food-ingredient platform, not human health benefit.
Key findings
- Green-tea kombucha had the lowest pH, highest acidity, and higher selected catechins, caffeine and acids; black tea had the highest EGCG. Green tea led in antioxidant assays without significant cytotoxicity under tested conditions. The nanoemulsion measured 110.03 ± 6.2 nm, PDI 0.28 ± 0.01, zeta +32.5 ± 0.5 mV and 91.66 ± 2.29% encapsulation, remained nanoscale for six months at 4°C and showed burst then sustained release.
Why this matters globally
Stable delivery systems may standardise variable fermented-food bioactives and enable value-added products. Industrialisation must address oxidation, cold chain, sensory quality, regulation and batch consistency.
Thai researcher contribution
Chiang Mai University integrated fermentation microbiology, bioactive chemistry, cell biology and nanoscale food-ingredient engineering.
Limitations to consider
Chemical antioxidant assays and cellular uptake do not establish beneficial bioavailability. There was no simulated digestion, animal/human study or sensory test. PDI 0.28 indicates some size dispersion; stability was only at 4°C, and compound-specific retention and release remain unclear.