Synthesis and characterization of antioxidant biomolecules

• Main Author: Roby, Mohamed Hussein
• Other Authors: Laboratoire d'Ingénierie des Biomolécules (LIBio), Université de Lorraine (UL), Université de Lorraine, Stéphane Desobry, Catherine Humeau-Virot
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: HAL CCSD 2014
• Subjects: Omega-3; DHA; Phenolic compounds; Vanillyl alcohol; Enzymatic esterification; Oxidative stability; Neuroprotection; Fish oil; Composés phénoliques; Alcool vanillique; Estérification enzymatique; Stabilité à l'oxydation; Huile de poisson; Biomolécules actives; Antioxydants; Acides gras oméga-3; Neuroprotecteurs; Estérification; [SDV.AEN]Life Sciences [q-bio]/Food and Nutrition; Antarc*; Antarctica
• Online Access: https://hal.univ-lorraine.fr/tel-01750806; https://hal.univ-lorraine.fr/tel-01750806/document; https://hal.univ-lorraine.fr/tel-01750806/file/DDOC_T_2014_0083_ROBY.pdf

Accès restreint aux membres de l'Université de Lorraine jusqu'au 2015-10-01 An efficient solvent-free bioprocess was developed for the synthesis of DHA phenolic ester, using the lipase B from Candida antarctica. The protocol developed here led to high-level production (440 g/L) of DHA vanillyl ester (DHA-VE) that exhibits interesting application potential as food ingredient. DHA-VE was characterized by a high stability and a high radical scavenging activity towards DPPH, ABTS and hydroxyl radicals. Neuroprotective properties of DHA-VE were also demonstrated in rat primary neurons exposed to amyloid-[beta] oligomers. Enzymatic esterification of DHA with vanillyl alcohol (VA) led to increased DHA levels in erythrocytes and brain tissues of mice fed DHA-VE-supplemented diet comparing with DHA. No visible toxicity of the ester was found. Enrichment of emulsions with DHA-VE improved significantly their oxidative stability whatever the conditions of storage, showing the potential of DHA-VE to enrich various food matrices with DHA while protecting them against oxidation. The enzymatic process was applied to salmon oil as a source of omega-3 polyunsaturated fatty acids (PUFA). The total conversion of VA (50 g/L) was achieved after 24 h of reaction, leading to the production of a wide variety of esters that mirror the initial composition of the oil. The crude reaction medium recovered from salmon oil alcoholysis exhibited a high stability together with high antioxidant properties in comparison with native salmon oil. In conclusion, the approach that consists in bringing phenolic compounds and PUFA-rich lipids together within a single structure is expected to provide stable bioactive ingredients that should broaden the scope of application of omega-3 PUFAs whose health benefits are increasingly sought Un procédé enzymatique sans solvant a été développé permettant la synthèse d'un ester phénolique de DHA. L'optimisation des paramètres réactionnels a permis d'atteindre des rendements élevés (440 g/L) d'ester de DHA et ...