Rapid determination of polyphenols and vitamin C in plant-derived products.
Polyphenols, widely spread in our diet by the consumption of plant food products, are commonly determined using Folin-Ciocalteu reagent that interacts with other different reducing nonphenolic substances and leads to an overestimation of polyphenol content. In this paper we report an optimized Folin-Ciocalteu method to specifically determine the contents of total polyphenols and vitamin C. After the optimal conditions for the colorimetric assay were set, solid-phase extraction (Oasis HLB (hydrophilic-lipophilic balance)) was carried out to eliminate the water-soluble reducing interferences including vitamin C. Colorimetric correction was thus performed by subtracting interfering substances contained in the water washing extract from the raw extract. Moreover, vitamin C present in the water washing extract can be destroyed by heating and thus colorimetrically deduced. This procedure was set up with synthetic solutions and validated on different extracts from fruit products.
Georgé
Stephane
S
Centre Technique de la Conservation et des Produits Agricoles (CTCPA), Site Agroparc, F-84911 Avignon Cedex 9, France. sgeorge@ctcpa.org
Brat
Pierre
P
Alter
Pascaline
P
Amiot
Marie J
MJ
D001205:Ascorbic Acid / Q000032:analysis*; D001628:Beverages / Q000032:analysis; D003124:Colorimetry / Q000379:methods; D005419:Flavonoids / Q000032:analysis*; D005504:Food Analysis / Q000379:methods*; D008982:Molybdenum; D010636:Phenols / Q000032:analysis*; D010945:Plants, Edible / Q000737:chemistry*; D059808:Polyphenols; D017973:Tungsten Compounds
D005419:Flavonoids; C029556:Folin's phenol reagent; D010636:Phenols; D059808:Polyphenols; D017973:Tungsten Compounds; D008982:Molybdenum; D001205:Ascorbic Acid