Free Fatty Acid Profiling of Rice Bran oils for Improving Shelf Life through Parboiling and Different Treatments

Abstract

The study aims to find out best treatment to increase shelf life of rice bran oil. Gas-Liquid Chromatography was, therefore, used to characterize essential and non-essential fatty acid profiling in oils extracted from rice brans treated with Phosphoric acid (1.0 and 1.5%), Acetic acid (5 and 7%), Hydrochloric acid (20 and 30 ml/kg of rice bran), Sodium metabisulphite (1.0 and 1.5%), rice bran oils extracted from rice treated at 100°C for one minute and steamed at 100°C for 20 minute. Results suggested that both the essential fatty acids i.e., linolenic acid (C18:3) and linoleic acid (C18:2) constitutes 1.47% and 31.34% of the total fatty acids in all the rice bran oil samples. Rice bran oil therefore can be utilized as a good source of linoleic (C18:2) an essential fatty acid. Oleic (C18:1), linoleic (C18:2) and palmitic (C16:0) acids were dominant fatty acids in all the parboiled (48.53, 27.83 and 18.03 respectively) and un-parboiled (43.39, 41.34 and 16.54% respectively) rice samples. The total content of fatty acid (∑FFA) such as mystiric acid, palmitic acid, oleic acid, ficosanoic acid, of parboiled bran oil was found higher than that of un-parboiled rice bran oil samples. Whereas, other fatty acids were present in higher quantities in bran oils of un-parboiled. The ratio of unsaturated fatty acids of each rice bran oil sample was much higher (~80%) than its ratio of saturated fatty acid (~20%). Results also indicated that parboiling increases the shelf life of bran oil by lowering proportions of unsaturated fatty acids and increasing saturated free fatty acids contents in rice bran oil. Results suggests that steaming and extrusion methods can be used as a good alternatives to harmful chemicals being used to make rice bran oils more stable for longer period of time.