EFFECT OF POSSIBLE CHLOROPHYLL BREAKDOWN PRODUCTS ON CANOLA OIL STABILITY

Three model compounds, maleimide, dimethylpyrrole, and trimethylpyrrole, were chosen as possible chlorophyll breakdown products (CBP), and their effect on the stability of canola oil was investigated. Stability tests were carried out at 60 degrees C in a forced air oven. Addition of these compounds to canola oil either individually (0.05-10.0 ppm) or together (0.05-1.0 ppm) resulted in an oil of lower stability. Bleaching with clay (1-5% w/w of the oil) completely removed dimethylpyrrole and trimethylpyrrole, while maleimide was poorly adsorbed. Citric acid and phosphoric acid treatment did not result in an appreciable decrease in the concentration of any of the three compounds. Alkali refining resulted in complete removal of maleimide. Dimethylpyrrole and trimethylpyrrole were present in trace amounts in the bleached oil along with significant amounts of maleimide. The deodorized oil contained only trace levels of dimethylpyrrole. Trace amounts (<5% of the original concentration) of dimethylpyrrole remained in tricapryloylglycerol that had been degummed, refined, bleached, and deodorized.