Recycling of food byproducts: Waste Cooking Oils exploitation for industrial purposes

Waste Cooking Oils (WCOs) are a mixture of exhausted vegetable oils, by-products of the food chain, which arise from private kitchens and catering industries. Most of WCOs are originated from cooking processes, usually by deep frying. The amount of available WCOs is impressive: only in the European Union (EU), more than 4 million tons of WCOs are produced yearly and despite the high amount of available oil, only the 25% is collected. It has been estimated that the amount of collected WCOs could increase from the current 1.2 L of WCO/capita/year to 8 L and that about 15 million tons of WCOs are inadequately disposed every year worldwide, main through public sewerage. The chemical composition of WCOs is of interest for develop sustainable recycling procedures and avoiding wrong disposal. Emerging fields of application of WCOs as raw materials are the bio-lubricants production, the formulation of biodegradable solvents and the formulation of composites. During the cooking process, the rich chemical composition of the oil is subjected to many chemical and physical transformations promoted by the high temperature and by the exposure to air.4 Several oxidation processes take place and a consistent production of volatile compounds is observed. In the present communication, a sustainable recycling procedure based on water degumming and clarification with bentonite of WCOs for the production of high values chemicals will be presented. The chemical profile of crude, degummed and clarified samples determined by headspace Solid-Phase Microextraction (HS-SPME) coupled with gas-chromatography, 1H NMR and ESI-MS will be discussed. Also, the variation of some physical parameters as color, density and flash point will be considered, including the optimization of the degumming procedure employing Design of Experiments for the specific production of natural biolubricants.