Antioxidant and antibacterial activity of tea and mate extracts
Laen...
Kuupäev
2026
Kättesaadavus
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Estonian University of Life Sciences
Abstrakt
Consumers are increasingly interested in natural, plant-based additives as alternatives to synthetic compounds in food products. This study investigated the polyphenolic profiles, total polyphenol content (TPC), total antioxidant capacity (TAC), and antibacterial activity of aqueous and 30% ethanolic extracts of green tea, matcha tea, black tea, and yerba mate. Commercial teas (Camellia sinensis) and mate (Ilex paraguariensis) were purchased in Tartu, Estonia. The tea and mate leaves were powdered (< 1 mm), and extracts prepared with water or 30% ethanol. Polyphenolic compounds were analysed using HPLC-DAD-MS, TPC was quantified as gallic acid
equivalents, and TAC was determined spectrophotometrically using the Folin-Ciocalteu method. Minimum
inhibitory concentrations (MICs) against Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, and
Campylobacter jejuni were determined by broth microdilution according to the EVS-EN ISO, 20776–1:2020
standard. In total, 28 polyphenolic compounds were detected, including hydroxybenzoic acids, hydroxycinnamic
acids, flavanols, flavonols, and tea pigments. Mate extracts were rich in chlorogenic acids, while tea extracts
contained higher proportions of flavanols, particularly epigallocatechin, epicatechin gallate, and epigallocatechin
gallate. Ethanolic extracts of mate (5.16 ± 0.02 mg GAE/mL) and green tea (4.68 ± 0.08 mg GAE/mL) had the
highest TPC, wheras matcha tea (5.50 ± 0.01 mg GAE/mL) and green tea (5.82 ± 0.00 mg GAE/mL) showed the
strongest TAC. In aqueous extracts, mate and green tea had the highest TPC (3.02 ± 0.34 and 1.77 ± 0.03 mg
GAE/mL, respectively), and the strongest TAC (4.05 ± 0.01 and 3.48 ± 0.10 mg GAE/mL). All extracts inhibited the
growth of S. aureus, with MIC values ranging from 0.06 to 0.27 mg GAE/mL, and green tea extracts showed the
strongest antibacterial activity. Mate extracts showed similar TAC and antibacterial activity in both aqueous and
ethanolic extracts. TAC correlated most strongly with TPC (rS = 0.8), and among individual compounds,
epicatechin gallate showed the strongest correlation (rS = 0.6). A moderate negative correlation (rS = − 0.6) between
TPC and MICs indicated that higher polyphenolic content was linked to stronger antibacterial activity. In summary,
ethanolic extracts of green tea were the most promising for further application in food composition due to their
strong antioxidant and antibacterial properties. These findings highlight the potential of tea and mate extracts as
natural alternatives to synthetic additives in the food industry.
Kirjeldus
Märksõnad
polyphenols, antioxidant, antibacterial, tea, mate, abstract