RESEARCH TITLE: The Effect of Cultivar and Ripening on Antioxidant System and PAL Activity of Pomegranate (Punica Granatum L.) Grown in Tunisia
COUNTRIES: Tunisia; France
CONDUCTED BY: Université Paul- Sabatier, Faculté de Pharmacie de Toulouse, France; Biodiversité et Valorisation des Bioressources en Zones Arides, Universite de Gabes, Tunisia.
PUBLISHED ON: Journal of Food Biochemistry
In this study, attempts were made to evaluate and to compare antioxidative defense system of three pomegranate cultivars (Punica granatum L.) (Chetoui, Gabsi and Garsi) at three ripening stages (UR, HR and FR). We report, for the first time, a decrease in superoxide dismutase, catalase, ascorbate peroxidase and PAL activities from UR to FR stages for all pomegranate cultivars, whereas glutathione reductase activity increased gradually and significantly. The highest phenolics and ascorbic acid contents were detected in UR fruits but anthocyanins and tannin contents varied greatly within cultivars. Using the DPPH assay, the free radical-scavenging activity of Garsi cultivar decreased significantly from UR to HR stages and finally increased in ripe fruit arils, whereas it decreases continuously during ripening of Chetoui and Gabsi cultivars. Significant correlations were detected between enzymatic and nonenzymatic antioxidants. Statistical analyses showed that stage and cultivar factors influenced significantly (P < 0.01) antioxidant system of pomegranate.
The study represents the first report on the activities of antioxidant enzymes at different stages of maturity of three cultivars of pomegranate. These results with good information to producer to make the connection with the maturity to produce pomegranates with well-optimized properties.