The Effect of Polishing Time on the Proximate and Antioxidant Properties of MARDI Warna 98 Red Rice

Abstract

MARDI Warna 98 (MW 98) is coloured rice, released in 2018 by the Malaysia Agricultural Research and Development Institute (MARDI), specifically as nutrient-dense rice. It has the potential to substitute traditional coloured varieties in East Malaysia, where most coloured rice is consumed. The bran of MW 98 is red, and the pigment would give an undesirable taste that most people refuse to consume, although the healthy properties lie in the bran.  A study was carried out to determine the bran removal degree that may affect the proximate and antioxidant properties of MW 98 rice.  The bran removal degree depends on polishing time, where a longer time removes more bran.  The bran was removed at four (4) polishing times (10, 20, 30 and 60 seconds), and unpolished rice was used as a control.  The proximate content evaluation was moisture content, carbohydrate, protein, fat and ash. At the same time, the antioxidant properties measured were total phenolic content (TPC), total flavonoid content (TFC), total anthocyanin content (TAC) and 2, and 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities.  Antioxidant parameters were measured spectrophotometrically.  The study proves the accumulation of health benefits of rice is in the bran, that unpolished rice significantly showed higher TPC (220.46 mg GAE/100g), TFC (943.30 mg CAE/100g), TAC (73.42 mg CYE/100g), as well as the protein (8.2g) and fat (2.3g) content. Whereas the carbohydrate content showed a significant increase with a longer polishing time (79.5g). Therefore, rice with the bran intact was highly recommended for a healthy diet.