Antioxidant Activities of Selected Milk Teas and Fruit Teas Using 2,2-Diphenyl-1-Picrylhydrazyl (DPPH) Assay

Milk teas and fruit teas are popular as a refreshment, but their percent antioxidant properties need to be determined. In this study, the antioxidant activities of selected commercialized milk teas (Matcha, Okinawa, and Winter Melon) and fruit teas (Green Apple, Kiwi, and Lychee) were determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay in terms of % scavenging activity. In that assay, the plates with milk teas and fruit teas were incubated in the dark and covered with aluminum foil for 30 minutes at room temperature before being measured for absorbance at 570 nm with a microplate reader. They were kept out of the light until they were evaluated for analysis. Within 30 minutes of incubation, the discoloration from purple to yellow was observed. Three (3) trials with three (3) replicates were carried out with negative control (water with sugar and creamer for milk tea and water with sugar for fruit tea) and positive control (Vitamin C). Using one-way ANOVA, the Matcha (mean = 62.9, sd = 2.6) Okinawa (mean = 46.4, sd = 5.9), and Winter Melon (mean = 61.6, sd = 2.8) milkteas have anti-oxidant activities when compared to the negative control (mean = 0.0, sd = 0.0) (p < .05) Both Matcha and Winter Melon have the best antioxidant activities, but not comparable to the positive control, Vitamin C (mean = 98.7; sd = 0.62) (p < .05). While the Green apple fruit tea (mean = 95.5; SD = 2.4) Kiwi fruit tea (mean = 97.3, SD = 1.5), and Lychee fruit tea (mean = 94.4; sd = 1.3) (p > .05) have comparable antioxidant activities when compared to the negative control (mean sd = 0.0). Kiwi fruit tea has the best antioxidant activity and comparable to Vitamin C (mean = 98.7; sd = 0.62). This study scientifically established that both Matcha and Winter Melon commercial milk teas have antioxidant activities of 61.6 to 62.9%. While the commercial Kiwi, Green apple, and Lychee fruit tea ranged from 94.4 to 97.3%. These antioxidant activities can be useful in preventing diseases brought by free radicals, which can be verified by conducting more studies.