Proposal of teaching materials of polyphenol analysis by visual evaluation and image analysis

Abstract

　We investigated a simplified polyphenol analysis suitable to school education. The analysis uses microplates and filter paper, and its reaction system is based on the folin-ciocalteu method. We examined the optimal reaction time in the assay. The evaluation is then conducted both visually and by the image analysis. As a result, both the microplate method and the filter paper method showed sufficient coloration in the reaction time of 10 min. The color changed visually in the microplate method with the gallic acid concentration of 0 μg/mL to 100 μg/mL. The same visible changes were observed in the filter paper method according to the gallic acid concentration of 100 μg/mL to 600 μg/mL. The proposed simplified analysis can appropriately evaluate the approximate polyphenol content amount and it is easily available to the situation of school education.