Biochemical properties and chromatographic investigation of rape seed oils in Bangladesh

Rapeseed oil is commonly used as cooking oil in Bangladesh especially in the rural areas and traditionally used with other food items in urban societies. This study evaluated the biochemical properties and chromatographic picturesque of various rapeseed oils namely mustard (wild and hybrid), rai (wild and hybrid) and canola oil in both raw and fried state. The qualitative tests such as acid value, iodine value, peroxide value, saponification value, unsaponifiable matter and Rechert-Meissl value were determined to differentiate the better quality of these consumable oils. Among five types of rapeseed oils, canola oil could be the best choice for consumption due to its lower erucic acid (6%) and high polyunsaturated fatty acids content, while the erucic acid content of mustard (wild), mustard (hybrid), rai (wild) and rai (hybrid) were 51.56, 64.82, 56.31 and 67.98% respectively. Canola oil also had the lowest level of acid value, peroxide value, saponification value and Reichert Meissl value but higher level of iodine value. On the other hand, rai (hybrid) fried oil was the lowest quality of consumable oil in comparison with other forms of rapeseed oils. Raw seed oils were also better than fried oils.