ACCELERATING BLEACHING OF SOYBEAN OIL BY ULTRASONIC HORN AND BATH UNDER SPARGE OF HELIUM, AIR, ARGON AND NITROGEN GAS

The aim of this study was to investigate the color (red and yellow) and pigments (carotenoid and chlorophyll) of soybean oil by the ultrasonic horn and bath under different conditions (gas, temperature, time and frequency). According design expert equation gas was a more important factor for the reduction of oil pigments and colors compared with other factors. For this purpose, the reduction percentage of red and yellow color of oil at the ultrasonic horn and bath was as follows: argon > air > helium > nitrogen. However, temperature and frequency could change the effect of gases during ultrasonic bleaching process. Increasing temperature and decreasing frequency reduced the color of bleached oil under diatomic gases compared with monoatomic gases condition.