Main content area

Antioxidative and prooxidative effects in food lipids and synergism with α-tocopherol of açaí seed extracts and grape rachis extracts

Melo, Priscilla Siqueira, Arrivetti, Leandro de Oliveira Rodrigues, Alencar, Severino Matias de, Skibsted, Leif H.
Food chemistry 2016 v.213 pp. 440-449
acai berries, alpha-tocopherol, antioxidant activity, antioxidants, emulsions, ethanol, flavanols, food safety, grapes, lipid peroxidation, lipids, procyanidins, seed extracts, solubility, soybean oil, synergism
Extracts of açaí seed and of grape rachis alone or in combination with α-tocopherol were evaluated as antioxidants in (i) bulk soybean oil, (ii) soybean oil liposomes and (iii) soybean-oil/water emulsions. The extracts made with 57% aqueous ethanol showed an antioxidant activity not dependent on concentration for grape rachis extracts and a concentration-dependent prooxidative activity for açaí seed extracts in bulk soybean oil. Both the extracts, however, protected liposome suspensions and oil/water emulsions against lipid oxidation. Synergism was demonstrated when extracts were combined with α-tocopherol, effects explained by the solubility of extract components in the water-phase and of α-tocopherol in the lipid-phase. Phenolic profiling of the extracts by U-HPLC-ESI-LTQ-MS was used to identify active antioxidants. Açaí seed and grape rachis extracts served as good sources of procyanidins and flavan-3-ols, imparted high antioxidant activity especially when combined with α-tocopherol and are suggested for protection of food oil/water emulsions.