Recovery of phenolic antioxidants from wine industry by-products.
The recovery process of the phenolic compounds contained in the wine industry by-products and their antioxidant activity were examined in this work. To this purpose, a combined process of liquid and supercritical solvent extraction was employed. At first the effect of various process parameters of the liquid solvent extraction--the type of solvent and the pretreatment of the raw material (composition (skins, seeds, stems) and crushing)--on the antioxidant activity of the extract was examined. It was shown that an extract of a higher antioxidant activity was obtained by using ethyl acetate as solvent and raw material free of stems. These extracts were further treated with supercritical carbon dioxide (SC CO(2)) at various extraction pressures, which resulted in their significant enrichment in phenolic compounds and the improvement of their antioxidant and organoleptic properties, especially at pressures higher than 100 bar. The antioxidant activity of the products was determined by using the Rancimat method, as well as a simple and not time-consuming free radical method. It was proved that both the ethyl acetate extracts and those treated with SC CO(2) had antioxidant activity comparable to that of antioxidants commonly used in industry, that is butylhydroxytoluene (BHT), a synthetic antioxidant, and Rosemary extract, a widely known natural one.
Louli
V
V
Laboratory of Thermodynamics and Transport Phenomena, School of Chemical Engineering, National Technical University of Athens, 9 Heroon Polytechniou Str., Zografou Campus, 157 80 Athens, Greece. svlouli@chemeng.ntau.gr
Ragoussis
N
N
Magoulas
K
K
D000085:Acetates; D000975:Antioxidants / Q000302:isolation & purification*; D002084:Butylated Hydroxytoluene; D002245:Carbon Dioxide; D002851:Chromatography, High Pressure Liquid; D009822:Oils, Volatile; D010636:Phenols / Q000302:isolation & purification*; D011312:Pressure; D027542:Rosmarinus; D027843:Vitis / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*; D014920:Wine / Q000032:analysis*
D000085:Acetates; D000975:Antioxidants; D009822:Oils, Volatile; D010636:Phenols; D002245:Carbon Dioxide; D002084:Butylated Hydroxytoluene; C007650:ethyl acetate; C053775:rosemary oil