The effect of lemon juice addition and cold storage on the total phenolic content and antioxidant activity of cold mate tea

Although mate tea, made from the infusion of the Ilex paraguariensis plant, is typically consumed cold, it should be properly prepared, stored, and consumed within the appropriate time frame to fully appreciate the tea's aroma and components. This study aimed to investigate the impact of adding lemon juice to mate tea and cold storage on the total phenolic content, antioxidant activity, and total mold and yeast count of the tea. It was hypothesized that the addition of lemon juice would increase the total phenolic content and antioxidant activity and extend shelf life. At the start of storage, the sample with 2% (v/v) lemon juice added showed the highest total phenolic content (14.06 ± 0.05 mg GAE/100 mL). The antioxidant scavenging activity of the tea samples was investigated using the DPPH (2,2-diphenyl-1-picrylhydrazyl) method. While all the studied sample showed higher DPPH inhibition than the control group, the highest value was found for tea sample with 4% lemon addition on 3rd day (97.618 ± 1.429). No mold or yeast growth was observed in the control group and the samples with 2% and 4% lemon juice addition up to day 21. In the sensory evaluation, the tea that contained 4% lemon juice was the most preferred. In conclusion, if mate tea is prepared and stored appropriately, it can maintain its antioxidant capacity for an extended period without the formation of harmful molds or yeasts and any deterioration in its sensory properties.