A novel bleaching approach: Microwave assisted sunflower oil bleaching and optimization

Abstract

The factors affecting the microwave bleaching of sunflower oil and the interaction between them were investigated and optimized by response surface methodology using a three-factor five-level central composite rotatable design. Microwave power, time and the amount of bleaching clay were selected as independent variables studied in the range of 70-120 W, 2-15 min, and 0.01-0.5%. The dependent variables that measure the bleaching efficiency and oil quality were evaluated as hue angle, chroma and totox value. Optimization was carried out by minimizing totox and chroma and maximizing hue angle. Hue angle, chroma and totox were found as 96.91, 37.66 and 23.31 under optimal conditions. Optimal microwave bleaching was successfully performed by using less bleaching clay (0.4%) and a shorter time (8 min) compared to the current industrial application without any adverse effect on oil quality. Hence, microwave bleaching is thought to be an alternative method for the bleaching of edible oils.

Microwave‐Assisted Bleaching of Olive Pomace Oil: Optimization of Bleaching Parameters and Comparison with Conventionally Bleached Oil

“…In contrast, the oil temperature reached 165 °C from ambient temperature in this study during the microwave method at optimum conditions with no vacuum application. The adsorbent dosage and time were reduced by 50% and 75%, respectively, in a previous study [ 13 ] on the MWB of sunflower oil. Even if the percentage reduction of clay in PO bleaching seemed lower compared to MWB of sunflower oil, the unit amount of clay was still considered to be high.…”

“…The preparation of the samples (20 g for each run) and the CEM Discover SP microwave reactor (Matthews, USA) settings for microwave bleaching were carried out according to the research by Seçilmiş et al. [ 13 ] The NPO was then centrifuged to enhance its filtration performance (Eppendorf 5810R, Eppendorf AG, Hamburg, Germany) at 9.000 rpm at 25 °C for 10 min. After centrifugation, the NPO was filtered using a 0.45 µm PTFE filter (ISOLAB, Germany) to separate the mix of clay/activated carbon under vacuum.…”

“…However, they only aimed to remove harmful components such as PAHs. [ 11,12 ] In the previous work of Seçilmiş et al., [ 13,14 ] it was stated that microwave‐assisted bleaching (MWB) is an effective method for sunflower oil bleaching.…”