Reduction of Anti-nutritional Compounds and Free Fatty Acids of Barley, Oats and Rice Bran Treated by Microwaves

At present, cereal bran is offered in our country without any processing to remove anti-nutritional compounds which can have adverse effects on consumers health. In this study, the effects of different conditions (power and time) of microwave treatment on the moisture content, anti-nutritional compounds (phytic acid and oxalic acid) and shelf life of barley, oat, and rice bran were evaluated. The samples were treated with microwave power of 2, 4, 6, 8 and 10 kW for 15, 30, 60, 90 and 120 s. The most optimum treatment to reduce moisture for barley, oat, and Iranian rice bran was 8 kW for 120 s. During the treatment at 8 and 10 kW microwave power for 120 s, around 50% loss in phytate and oxalate content was observed. There was no statistically significant difference between the results obtained for 8 and 10 kW radiation power. Therefore, treatment at 8 kW for 120 s to reduce phytate and oxalate in brans was identified as the optimal treatment. During the 28-day storage period under accelerated conditions, no statistically significant difference was observed between the moisture content and the percentage of free fatty acids in the treated samples with power of 8 and 10 kW. The results of the present study showed that treatment with 8 kW microwave power for 120 s for barley and rice brans and 10 kW for oat bran significantly reduced the amount of moisture, anti-nutritional factors of phytic acid and oxalic acid in all three bran samples and also reduced the amount of moisture, reduced lipase activity and production of free fatty acid during the 28-day accelerated storage period.