IN VITRO ANTIOXIDANT PROPERTIES OF POMEGRANATE (PUNICA GRANATUM) PEEL POWDER EXTRACT OBTAINED AS COPRODUCT IN THE JUICE EXTRACTION PROCESS

The aim of this work was to determine the total phenol (TPC), total flavonoid (TFC), tannins contents (TCs) and antioxidant properties of pomegranate (Punica granatum) peel powder coproduct (PPP) in view to its application in the food industry as ingredient. The antioxidant activity of the PPP was determined by means of four different antioxidant tests (2,2-diphenyl-1-picrylhydrazyl, ferric reducing power, ferrous ion-chelating and thiobarbituric acid reactive substance) and the TPC, TFCs and TC were also determined. The PPP showed a content of TPC of 54.84mg gallic acid equivalents/g sample; a TFC content of 42.36mg rutin equivalent /g sample and a TC of 21.25mg catechin equivalent/g sample. As regards the antioxidant properties, PPP has good antioxidant activity at all concentrations tested (0.2, 0.5, 1 and 10g/L) and all methods used, but in general terms, this activity is lower than that shown by the positive control (butylated hydroxytoluene) used. PRACTICAL APPLICATIONSThe pomegranate peel extracts could be suitable for applications on the food industry because they are an important source of phenolic, flavonoids and tannins compounds; indeed, the antioxidant properties of this extract could be very appreciated in a big number of food processing to avoid its spoilage during processing but also during storage period. Other important reason for their suitability is their natural origin, which consumers find comforting.