Physicochemical Properties of Indonesian Pigmented Rice (Oryza sativa Linn.) Varieties from South Sulawesi

Abstract

Pigmented Rice (PR) is one of the valuable food crops used in indigenous medicine. Thirteen PR varieties were collected from 3 climatic zones of South Sulawesi, Indonesia and analyzed for grain dimension, color and proximate composition. The PR were extracted using acidic ethanol and then measured their total phenolics, anthocyanins and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity. Grain size determination showed that the length of the rice was in the range of 5.60-6.82. There was no significant different (p>0.05) in rice length and length/width ratio. The colorimetric results indicated that the darkest black glutinous rice had the lowest brightness parameter L* value which was negatively correlated with its total anthocyanin (r = -0.673) and phenolic (r = -0.559) contents. Proximate analysis results showed that all of PR varieties fulfilled the water content limit (#14%). The total contents of ash, fat, protein, crude fiber and carbohydrate were in the range of 1. 19-2.13, 1.06-3.05, 7.24-14.02, 0.66-0.99 and 71.29-77.14%, respectively. The anthocyanin and phenolic contents of black glutinous rice extracts were in the range of 94.70-202.46 mg Cy-3-glc/100 g db and 292.74-746.25 mg GAE/100 g db, respectively, which were higher than the black rice (66.08-113.83 mg Cy-3-glc/100 g db and 119.74-230.10 mg GAE /100 g db) and the red rice (0-12.85 mg Cy-3-glc/100 g db and 12.52-64.52 mg GAE/100 g db). Antioxidant activity was positively correlated with total phenolic (r = 0.886) and anthocyanin (r = 0.650) compounds. The data suggests the potency of black glutinous rice as a part of nutraceutical product formulation.