The triple defensive barrier of phenolic compounds against the lipid oxidation-induced damage in food products

Background: Although prooxidant activities have also been described, phenolic compounds can act as chelating and free radical scavengers. These protective functions would be their first and second defense barriers against the lipid-induced damage in foods. In addition, recent studies have shown that they can act as lipid-derived carbonyl scavengers, therefore avoiding that these toxic and very reactive compounds can modify essential food components such as aminophospholipids, amino acids, and proteins. These results point out to phenolic compounds also as responsible for a third defense barrier against the lipid oxidation-induced damage in foods. Scope and approach: This review collects the scattered information existing on the role of phenolic compounds as lipid-derived carbonyl scavengers and introduces a general lipid oxidation scheme in which the triple function of phenolic compounds can be clearly understood by pointing out where they are acting as a function of their structure. Key findings and conclusions: The structural requirements for the three barriers are different and phenolic compounds are suggested to be classified into seven groups as a function of the number and kind(s) of function(s) exhibited. This better classification and understanding of how different phenolic compounds protect foods will help to the food industry to employ the most appropriate phenolic compounds in each formulation and will also contribute to better understand the biological functions of these compounds.We are indebted to José L. Navarro for technical assistance. This study was supported in part by the European Union (FEDER funds) and the Plan Nacional de I + D of the Ministerio de Economía y Competitividad of Spain (projects AGL2012-35627 and AGL2015-68186-R)Peer Reviewe