Determination of Total Antioxidant Capacities as Ascorbic Acid Equivalent of Tea Extract Samples from Different Brands Using Digital Image-Based Colorimetric Detection Method

Abstract

In this study, the Digital Image-Based Colorimetric Detection Method developed by Bakırdere et al. was used to find the TAC (Total Antioxidant Capacity) value of tea samples from different brands. To determine the total amount of antioxidants in tea samples, the CUPRAC (cupric ion reducing antioxidant capacity) method, which is widely used in antioxidant determination, was combined with a digital image-based colorimetric detection system. To use in our study, a box with opaque wood material measuring 24 cm x 19 cm x 17 cm (width/length/depth) was designed and manufactured. In the analysis, the oxidation reaction between the chromogenic copper(II)-neocuproine (Cu(II)-Nc) reagent and antioxidants was utilized. The color change that occurs as a result of the oxidation was calculated using an application on smartphones. In our study, analyzes were performed on 4 different brand tea extract samples (tea A, tea B, tea C, tea D) to determine the total antioxidant capacity of ascorbic acid equivalent. The TAC values for ascorbic acid equivalent in tea extract samples were found as 380 ± 8 mg/L (tea A), 402 ± 4 mg/L (tea B), 213 ± 3 mg/L (tea C), 232 ± 4 mg/L (tea D) using the digital image-based colorimetric detection systems.