Chemical degumming of canola oils

Abstract

Crude oil produced from 2 varieties of canola (low thioglucoside rapeseed), i.e., Candle and Tower, were chemically degummed using 54 reagents. Phosphorus, iron, calcum and free fatty acid levels, and Lovibond colors were measured. Inorganic and organic acids or their anhydrides gave the best results in terms of phosphorus removal. Phosphoric, nitric and citric acids, and maleic anhydride were used in laboratory refining tests to determine the effects of chemical degumming on the refining process and on refined oil quality. Citric acid and maleic anhydride gave residual phosphorus levels of less than 50 mg/kg, and after refining, resulted in the best quality oil in terms of color, flavor and stability. The chemical degumming agents behaved similarly for expressed, solvent-extracted and blended oils of both varieties tested. One anomalous result was observed: Candle oil was not efficiently degummed by hydrocholoric acid, whereas the Tower oil gave excellent results. The experiments suggest that chemical degumming can significantly improve the quality of crude canola oil, and will lead to improved final products at lower cost to the refiner.