Antioxidant activity of 100% and 80% methanol extracts from barley seeds (Hordeum vulgare L.): stabilization of sunflower oil

The antioxidant potential of 100% and 80% methanol extracts from the seeds of three barley varieties (Jou 83, Jou 87 and Haider 93) was assessed. The extract yields from barley seeds ranged from 3.23% (Haider 93,100% methanol) to 5.31% (Jou 83, 80% methanol). The total phenolic contents, DPPH radical scavenging activity (IC50 values) and inhibition of linoleic acid oxidation of barley seed extracts (BSE) were determined to be 88.1-145.7 mg/100g, 90.8-168.6 μg/mL and 62.6-74.6%, respectively. The antioxidant effectiveness of BSE was also assessed by stabilizing sunflower oil (SFO) with BSE at a concentration of 600 ppm (oil weight basis). The stabilized (treated with extract) and the control (without extract addition) SFO samples were subjected to accelerated (oven heating at 60ºC for 30 days, 8 h heating cycle/day) storage. These were analyzed at regular intervals for the extent of oxidative changes according to the measurements of their contents of peroxide value, para-anisidine value, conjugated dienes and conjugated trienes. Generally, the 80% methanol extract of barely seeds demonstrated better antioxidant action than the 100% methanol extract. The antioxidant activity of BSE was also found to be considerably varied among the varieties tested. The present results suggest that antioxidant extracts from barely seeds might be used to protect vegetable oils from oxidation.