ReviewA review on enzymatic synthesis of aromatic esters used as flavor ingredients for food, cosmetics and pharmaceuticals industries

- Flavors are widely used as additives in food and pharmaceutic industries.
- Aromatic esters via biotechnological synthesis are labeled as natural flavor.
- Use of immobilized lipase for esterification and transesterification reactions.
- Production of aromatic esters using mild conditions and low cost.
- Enzyme concentration, molar ratio and temperature affect reactions conversion.

BackgroundMany sectors of industry, mainly food, cosmetics and pharmaceutics, have increased their interest in esters due to their flavor property. Flavor esters that possess an aromatic ring in their molecular structure are also known as aromatic esters. These esters are widely found in nature (fruits and plants) and the synthetic (i.e. via chemical) and natural routes (i.e. via direct extraction from nature or via biotechnology) are suitable for their biocatalysis.Scope and approachIn this context, from the industrial point of view, enzyme-catalyzed reactions are the most economical approach to reach final green products with no toxicity and no harm to human health. The present article gives an overview of the aromatic esters synthesis, considering the main effects in the reaction media conditions and enzymes used. This review also describes applied trends in enzymatic-catalyzed reactions, pointing alternatives to production, like ultrasound-assisted reactions and process optimization of aromatic esters. Furthermore, this work presents perspectives concerning the biological potential of these esters and recent advances in their encapsulation.Key findings and conclusionsLipases play an important role in the aromatic esters production, with several advantages over synthetic route. Lipase-catalyzed reactions usually follows Ping-Pong Bi-Bi or ternary complex (order Bi-Bi) mechanism. The study of the process parameters and their interaction are very important to understand the system optimization and achieve the maximum reaction yield to scale up. Aromatic esters can present some biological activities, in addition to their fragrances, which increases the interest in the encapsulation of these compounds.

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