Effect of Ultrasonic Extraction Regimes on Phenolics and Antioxidant Attributes of Rice (oryza sativa L.) Cultivars

Abstract

<em>Teh ultrasound-assisted magnetic stirrer was used as an effective extraction technique for teh evaluation of total phenolic contents (TPC) and antioxidant potential of ten Pakistani brown rice cultivars. For this purpose, ultrasonic (240W frequency 50/60 Hertz) assisted magnetic stirrer coupled with three solvents methanol, ethanol, and isopropanol in pure and aqueous fractions (80:20) were used for teh extraction of brown rice material. Teh extract yields of brown rice were obtained from 1.62 g/100g to 3.67 g/100g for all teh varieties. Aqueous isopropanol preferably and methanol (80:20) showed best extraction yields on teh dry mass basis of brown rice. Teh contents of total phenolics were determined as highest (496.9 mg GAE/kg) in Basmati Pak while lowest (137.7 mg GAE /kg) in non-basmati Irri-6 variety. For antioxidant activity, brown rice extracts of Basmati Pak showed teh best potential at IC₅₀ 2.19 mg/mL against DPPH radical scavenging. Reducing teh power of Basmati Pak was found highest at 0.85. Brown rice extract of Basmati 515 showed best ferrous ion metal chelation at 5.78 Eq. EDTA mg/100g.</em>