Frying is a very complex process and the applied conditions often overwhelm most endogenous and added antioxidants. Synthetic antioxidants such as butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), and tert-butylhydroquinone (TBHQ) are often added to processed oils to retard oxidative degradation during storage and frying; however, beside their poor performance under frying conditions, consumers' acceptance of synthetic antioxidants remains negative due to their perceived detrimental effect on human health. Consequently, there is a growing interest in the search for effective natural antioxidants for frying applications, notably, from phenolic components of common spices and herbs. The present study provides an overview of the literature on natural antioxidants, sources, and their performance under frying conditions.
Practical applications: Sources and performance of natural antioxidants during frying were reviewed. Despite abundance of data on the radical scavenging activity and antioxidant potency of some natural antioxidants under storage conditions, there is still a dearth of information on their activity during frying. This study revealed a number of under-exploited sources of natural antioxidants that could be used to improve the stability of frying oils.