Antioxidant Activity of ‘Broken Skin’ Purple Rice, ‘Skinned’ Purple Rice, and Purple Rice Stem Organically Cultivated in Indonesia

Abstract

This research has been carried out to determine the activity of purple rice stem, ‘broken skin’ purple rice and ‘skinned’ purple rice. Preparation of materials includes the collection of purple rice from ‘Tuah Sakato’ farmer group that cultivates the rice using organic methods. The extraction method used is maceration extraction with n-hexane methanol. The rotary evaporator extracts each solvent variation from the solvent. Concentrated extracts from each solvent were tested for their antioxidant activity using the DPPH method (2,2-diphenyl-1-picrylhydrazyl) at five concentrations within the range of 800 – 6000 ppm, based on the sample varieties. The comparison used is ascorbic acid (vitamin C). Determination of the value of antioxidant activity had used the IC50. The results showed that the highest antioxidant activity was possessed by purple rice stems, as evidenced by the IC50 value of 1.474 ppm, followed by ‘broken skin’ purple rice with IC50 of 4.130 ppm, and the lowest was ‘skinned’ purple rice with IC50 of 98.95 ppm. Purple rice stems have the highest antioxidant activity since the antioxidant compound still intact without any further process. Then, ‘broken skin’ purple rice has higher antioxidant activity than ‘skinned’ purple rice because the former still has epidermis that contains high antioxidants. High enough antioxidant activity makes this purple rice an alternative food source that can ward off free radicals causing degenerative diseases due to unhealthy modern lifestyles.