Degumming Alternatives for Edible Oils and Biodiesel Production

Vegetable oils are predominantly composed of triacylglycerols (>95%), besides that, a wide variety of minor components including free fatty acids, phystosterols, tocopherols, colour pigments, metals and phospholipids are present in oils and fats. The presence of phospholipids in vegetable oils can cause oil darkening during the deodorization step and the inactivation of the lipases during the enzymatic transesterification process. The first step of the refining process is the degumming, which is designed to remove phospholipids. Traditional degumming processes such as water degumming and acid degumming cannot guarantee the low phosphorus content required for physical refining. Enzymatic degumming is a new process that uses enzymes known as phospholipases, which hydrolyze the phospholipids releasing fatty acids or diacylglycerols, thus increasing the oil yield. Moreover, due to the reduced reaction time and/or to the increased productivity, the ultrasonic technique has also been recently employed in association with degumming processes. Therefore, the purpose of this review is to present relevant studies on enzymatic degumming for edible oils and biodiesel production, from enzymatic catalysis, considering the most recent alternatives for product quality improvement and process costs reduction, with a focus on the simultaneous use of enzymatic degumming and ultrasonic technique.