Comparison Between Emerging and Conventional Methods for Edible Oils Bleaching.

Area of Science:

• Food Science
• Chemical Engineering
• Materials Science

Background:

• Industrial oil bleaching (IB) traditionally uses acid-activated clay, leading to issues like long filtration times, oil loss, and waste generation.
• High temperatures and extended periods in IB contribute to triacylglycerol degradation, increased oil acidity, and undesirable byproduct formation.

Purpose of the Study:

• To investigate and compare the effectiveness of traditional industrial bleaching methods with emerging technologies for oil purification.
• To highlight the drawbacks of current industrial oil bleaching practices and explore innovative alternatives.

Main Methods:

• Review of adsorption isotherms (Freundlich, Langmuir), kinetic studies (pseudo-first-order, pseudo-second-order), and thermodynamic analyses.
• Comparison of conventional acid-activated clay bleaching with emerging methods such as ultrasound (US), microwave (MW), high-voltage electric field (HVEF), and membrane (MB) assisted bleaching.

Main Results:

• Acid-activated clay bleaching results in prolonged filtration, oil loss, and environmental concerns.
• Emerging technologies show potential to enhance sorption capacity, reduce adsorbent quantity, and lower processing time and temperature.
• Adsorption processes are characterized by heterogeneous multilayer adsorption, with kinetics often following pseudo-first or pseudo-second order models.

Conclusions:

• Novel bleaching technologies offer promising, cost-effective alternatives to traditional acid-activated clay methods.
• These advanced techniques can mitigate the environmental impact and operational inefficiencies associated with conventional oil bleaching.
• The thermodynamic analysis indicates that the bleaching processes are endothermic and spontaneous, driven by entropy gains.