Physical properties and fatty acid profiles of oils from black, kidney, great northern, and pinto beans

Four common beans (black, kidney, great northern, and pinto) were extracted with hexane and found to contain about 2% triacylglycerols. The fatty acids in these bean oils were mainly linolenic (41.7-46 wt%), linoleic (24.1-33.4 wt%), palmitic (10.7-12.7 wt%) and oleic (5.2-9.5 wt%). Because of the high levels of polyunsaturated fatty acids, the bean oils had iodine values between 174 and 177 g/100 g (compared to 130 g/100 g for soybean oil). Yet, the bean oils exhibited high oxidative stability due to the presence of high amounts of tocopherols (2,670-2,970 ppm). The bean oils had lower pour points (-18 to -11 °C) compared to -9 °C for soybean oil. Among the four bean oils, kidney bean oil had the highest acid value (15.4 mg KOH/g) and kinematic viscosities over a wide range of temperatures.