Ultrasound-assisted bleaching of canola oil: Improve the bleaching process by central composite design

The goal of this study is to improve the bleaching process of canola oil by using ultrasound treatments under various parameters. The first of these parameters was the temperature (45 °C-75 °C)/ultrasonic power (20%–60%), the second was the amount of bleaching earth (0.1%–2% w/w), and the third was the contact time (2–15 min). The response surface central composite design was created and the bleaching parameters for canola oil were optimized based on the spectrophotometric analysis at 446 nm and responses to the lovibond color scales. The optimum conditions obtained by ultrasonic treatment of canola oil bleaching were compared with the conventional bleaching conditions. Especially, properties of bleached oil such as free fatty acids, peroxides, p-anisidine values, conjugated diens and triens, totox, fatty acid compositions and red-yellow colors have been evaluated. The results showed that integration of the ultrasonic treatment into the bleaching process, could possibly reduce the applied oil temperature by 25%, the contact time by 50%, and the color value by 6–34% compared to the conventional method. © 2018 Elsevier LtdFirat University Scientific Research Projects Management Unit: FDK-2017-3131This work has been financially supported by the Yildiz Technical University Scientific Research Projects Unit under the Project Number of FDK-2017-3131 . The authors would like to thank Dr. Salih Karasu for support

Combined design as a useful statistical approach to extract maximum amount of phenolic compounds from virgin olive oil waste

Combined design composed of mixture design and response surface methodology (RSM) was firstly applied for simultaneously optimization of extraction conditions (solvent concentration and ultrasonic conditions) to obtain maximum amount of phenolic compounds from virgin olive oil waste. Various water:methanol (0-1000 mL/L) mixtures were used as solvent under different ultrasonic temperature (30-60 °C), amplitude (20-100%) and time (10-30 min) conditions. Phenolic yields of the extracts ranged from 1.6 to 45 mg/g. Generally, increase of time, temperature and amplitude raised extraction yield; however, at elevated temperature and amplitude levels, phenolics were degraded. Optimum ultrasonic condition varied depending on the solvent concentration, that is reason of why combined design is necessary. Optimum water:methanol concentration was 499:511 mL/L; optimum ultrasonic temperature, amplitude and time was 60 °C, 13.71% and 21.05 min, respectively. Findings highlighted that combined design has potential to be used in many areas of food industry for optimization of many parameters with low experimental points. © 2016 Elsevier Ltd