29 Sep Antibacterial Potential of Heated Polyunsaturated Oils
Introduction
The process of discarding biomass residues in a sustainable way with minimal environmental impact has led to the concept of biorefining which is increasingly present in the forest, agriculture and agri-food industries, in general. It definitely forms a significant part of the response to the growing scarcity of resources combined with the increase in the global population and pollution. It results in the reuse and maximum transformation of biomass by proposing alternatives to the landfilling and incineration of residues, byproducts and co-products of these industries.
Pesticides are found in 90% of the streams and 55% of the groundwater manly because of agricultural activities, weeding and industrial sites. Airborne contamination would be found around farms to pose a risk to non-targeted organisms, primarily to users in a professional context (Baldi et al., 2013; van der Werf, 1997). Furthermore, the development of resistance of pathogens to chemical pesticides is also drawing attention (Russell, 2004). Thus the need for alternative methods such as the use of antimicrobial substances from natural sources, that may be less toxic to human health, and, thanks to the action of multiple compounds, less prone to resistance development.
Saturated (palmitic, stearic), monounsaturated, omega-3 and omega-6 fatty acids as well as some vegetable oils such as olive oil have been tested by for their antimicrobial potential (Desbois and Smith, 2010; De Carvalho et al., 2008, Dilika et al., 2000). The main conclusions were that linoleic acid would be more effective than oleic acid, in turn, more effective than the unsaturated fatty acids of smaller carbon chains. Saturated fatty acids had no significant antibacterial effect.
Used oils from frying operation form residues that could be valorized for a second life. These thermally treated oils contain trans fatty acid isomers which evolve towards low levels of cyclic fatty acid monomers (CFAM) during frying operations (Cherif et al., 2019, Destaillats and Angers, 2005; Sébédio and Juaneda, 2006). CFAM are known to interact significantly with enzymes involved in the liver metabolism in the rat (Mboma et al., 2018). However, data on their potential interactions with bacterial enzymes are scarce or non existant