Lipophilization of Phenolic Fractions issued from Natural By-products and Antioxidant Evaluation of the Resulting Compounds  
Grajeda-Iglesias C.1,*, Salas E.2, Bayrasy C. 3, Baréa B.3, Villeneuve P.3, Figueroa-Espinoza M. C.1
1Montpellier SupAgro, UMR 1208 IATE, 2 Place Viala, F-34060 Montpellier, France.
2Universidad Autónoma de Chihuahua, Facultad de Ciencias Químicas. Universitario s/n, Campus universitario N° 2, CP 31125. Chihuahua, Chihuahua, Mexico.
3CIRAD, UMR 1208 IATE, 2 Place Viala, F-34060 Montpellier, France.

Tropical plant by-products represent a significant source of bioactive compounds as polyphenols, which constitute one of the most widely distributed groups of plant metabolites possessing interesting functional properties as i.e. antioxidant. Low-grade green coffee beans are one of the most world’s abundant by-products, and they are an important source of antioxidants, mainly chlorogenic acids. Hibiscus sabdariffa or roselle flower, is not considered to be an important product in an economical level; however, it is consumed worldwide as a cold beverage or a hot drink after infusion of dried sepals and calyces. The resulting exhausted flower is a potential natural source of polyphenols, such as protocatechuic acid. These antioxidant compounds have a hydrophilic character that limits their use in lipid-rich matrices, like food, pharmaceutical or cosmetic products. To counteract this behavior, lipophilization can be applied as a strategy to increase their solubility in lipidic media by esterifying them to a fatty alcohol. We present the results of the lipophilization and the antioxidant activity (measured by the CAT, DPPH, and ORAC methods) of a homologous series of chlorogenates and protocatechuates (from butyl to octadecyl), used as models of the phenolic compounds derived from green coffee and roselle, respectively. A cutoff effect was observed.

*E-mail address: claudia-grajeda.iglesias@cirad.fr