Acid and Enzymatic Degumming of Wheat Germ Oil

The objective of this study was to evaluate the efficiency of acid and enzymatic degumming for crude wheat germ oil refining. Both hexane extracted and mechanically pressed oils were examined in the study. The effects of five variables on acid degumming efficiency were examined: temperature, time (mixing type: 60 min stirring versus 2 min homogenization), water:oil ratio, acid type (phosphoric and citric acids), and acid concentration. Phosphoric acid was more effective than citric acid for removing phospholipids from crude wheat germ oil. Phosphoric acid degumming at 70°C, 2Â min homogenization, phosphoric acid concentration of 0.05%, and water:oil ratio of 7.5% resulted in the lowest (989Â mg kg^-1) residual phosphorus content in the oil. The oil yield under these degumming conditions was 93.5%. About 76% of the total tocopherols were lost during phosphoric degumming of hexane extracted oil. Tocopherol loss was much lower (19%) for mechanically pressed oil degummed under the same conditions as hexane extracted oil. A commercial phospholipase (GumZyme) was also evaluated for WGO degumming. The lowest phosphorus level achieved in the enzymatically degummed oil was 573 mg kg^-1. Enzymatic degumming was more effective than acid degumming in removing phospholipids from wheat germ oil.