EFFECT OF HEAT-TREATMENTS ON CANOLA PRESS OILS .1. NON-TRIGLYCERIDE COMPONENTS

Increasing heat treatment given to canola seed prior to pressing resulted in press oils with progressively increasing contents of non-triglyceride components. Phosphorus and chlorophyll contents ranged from 13 ppm and 7 ppm, respectively, in cold press oil to 64 ppm and 68 ppm, respectively, in oil from heated seeds. Refining reduced the amount of these components to 19 ppm and 60 ppm, respectively, in degummed oil and to 4 ppm and 11 ppm, respectively, in bleached oil. Oil with the lowest amount of non-triglyceride material was obtained by cold pressing and/or bleaching. The major sterols were beta-sitosterol (55%), campesterol (35%) and brassicasterol (10%), and the major tocopherols were gamma (60%), alpha (30%) and sigma (10%). The content of sterols and tocopherols ranged from 620 to 773 mg/100 g and from 47 to 64 mg/100 g, respectively, in the press oils. The total content of sterols was reduced by 15% and a further 1% on degumming and bleaching, respectively. The total tocopherol content was reduced by 20% and 60% on degumming and on subsequent bleaching. Refining had no effect on the sterol isomer ratio, but there was a significant relative loss of alpha-tocopherol on bleaching.