Enzymatic Preparation of Novel Antioxidants by Natural Phenolics

Food additives, synthetic or natural, are added to products to protect or improve their flavour, colour, taste, texture, appearance, or nutritive value. These could be preservatives (salt, sodium benzoate), antioxidants (ascorbate, butylated hydroxtanisole [BHA]), emulsifiers (tetrasodium pyrophosphate, ascorbyl palmitate), or flavour enhancers (monosodium glutamate, citric acid), among others. Traditionally, synthetic phenolic compounds were widely used in lipid-based food, drugs, cosmetics, or even industrial products such as gasoline and rubbers, in order to protect them from oxidation. However, commonly-used synthetic phenolics including BHA, BHT (butylated hydroxytoluene), TBHQ (tert-butylhydroquinone), and PG (propyl gallate) may not be safe at high concentrations and long-term ingestion which could increase the health risk. These synthetic antioxidants are simple, low molecular weight lipophilic phenolics with high bioavailability and low excretion rate. Therefore, interest in natural sources of antioxidant phenolics has intensified. However, naturally occurring phenolics are often hydrophilic and high molecular weight compounds and may not be easily incorporated into food lipids and other lipophilic media. Therefore, investigating the production of semi-synthetic antioxidants by lipophilization/acylation has been practiced for a few decades. In comparison with chemical synthesis of lipophenols, enzymatic modification is preferred as it offers a simpler, safer and more economical process. However, absorption and metabolism of such products also needs to be investigated. Thus, this presentation provides introduction about application of synthetic phenolic additives, along with the production of lipophilic derivatives of natural phenolic compounds from the work carried out in both our lab and in other places.