Lipofilizacion

J. Agric. Food Chem. 2005, 53, 2779−2787

2779

REVIEWS
Phenolic Acids Enzymatic Lipophilization
MARIA-CRUZ FIGUEROA-ESPINOZA*,†,‡
AND

PIERRE VILLENEUVE†

Lipotechny Laboratory, UMR IATE, CIRAD, TA 40/16, 73 rue J. F. Breton, 34398 Montpellier Cedex 5, France, and ENSIA-SIARC, 1101 avenue Agropolis - CS 24501, 34093 Montpellier Cedex 5, France

Lipophilization is the esterificationof a lipophilic moiety (fatty acid or fatty alcohol) on different substrates (phenolic acid, sugar, protein, ...), resulting in new molecules with modified hydrophilic/ lipophilic balance. This reaction can be obtained chemically or enzymatically using different enzymes. Phenolic acids possess interesting biological properties (antioxidant, chelator, free radical scavenger, UV filter,antimicrobial, ...), but because of their relatively low solubility in aprotic media, their application in oil-based products is limited. Therefore, the esterification of their carboxylic acid function with a fatty alcohol enhances their hydrophobicity and results in a multifunctional amphiphilic molecule. Enzymatic lipophilization of phenolic acids is nowadays studied for potential industrial applications.Different systems have been proposed to perform the reaction yield [free or immobilized enzymes (lipase, feruloyl esterase, tannase, etc.), free or added organic solvent, addition of surfactant, microemulsion system, etc.]. Some of the functional properties of these esters have been demonstrated. This review presents a panorama of the advances in this field.
Keywords: Phenolic acid; lipase;lipophilization; esterification; antioxidant; emulsion; multifunctional; additive

INTRODUCTION

A large number of phenols and phenol derivatives occur in nature, particularly in the plant kingdom. Phenolic acids and derivatives, together with flavonoids, stilbenes, and lignans, constitute the polyphenols, which are secondary plant metabolites and form part of the human diet. Polyphenols participatein the defense system of plants and possess antioxidant and several biological properties. The phenolic acid family is composed by the cinnamic (C6C3) and the benzoic (C6-C1) acid derivatives (Figures 1 and 2), characterized by containing a benzene ring substituted with one or more hydroxy or methoxy groups and a carboxylic group. The cinnamic derivatives also contain a propenoic chain (1).Phenolic acids are natural hydrophilic antioxidants, which occur ubiquitously in fruits, vegetables, spices, and aromatic herbs. They are of particular interest because of their potential biological properties, such as antioxidant, chelating, free radical scavenging, anti-inflammatory, antiallergic, antimicrobial, antiviral, anticarcinogenic, and UV filter properties (2-8).
PHENOLIC ACIDS ASANTIOXIDANTS

According to Halliwell (9), an antioxidant is any substance that, when present at low concentrations compared to those of
* Corresponding author [telephone (00) 33 4 99 23 21 57; fax (00) 33 4 67 61 70 55; e-mail figueroa@cirad.fr]. † UMR IATE, CIRAD. ‡ ENSIA-SIARC.

an oxidizable substrate (proteins, lipids, carbohydrates, DNA), significantly delays or prevents oxidation of thatsubstrate. Antioxidants are frequently employed to prevent lipid oxidation in foods, cosmetics, and pharmaceutical products, as they slow the oxidation of unsaturated fats and oils and the concomitant formation of bad smells and tastes, preserving food quality. According to Frankel and Meyer (10), the requirements to select the most effective antioxidant for a food are to understand the true protectiveproperties of the antioxidant, to identify the substrates being oxidized, the location of the antioxidant in the system, and the effect of other components on the antioxidant activity, and to determine the relevance of a model system to a real food. Many sources of antioxidants are available in nature. Extracts rich in natural antioxidants as phenolic compounds can be obtained from raw vegetable...