Quality of pumpkin fruits in relation to electrochemical and antioxidative properties

Abstract

The aim of this study was to investigate the electrochemical characteristics and antioxidant activity of pumpkin fruits and to determine the influence of these properties on the fruit quality of pumpkins grown at the experimental field of Lithuanian Agricultural University in Kaunas. Eleven cultivars of Lithuanian and Polish origin were chosen for the experiment: 'Stofuntovaja', 'Bambino', 'Kroska', 'Zemciuzina', 'Miranda', 'Golosemiannaja', 'Justynka', 'Ambar', 'Amazonka', 'Karowita' and 'Otylia'. The electrochemical parameters were measured in homogenized fresh fruit samples. P value (as combined parameter of pH, redox potential and electrochemical conductivity) was used for the evaluation of pumpkin quality. The lowest P value and redox potential in the pumpkin fruits indicated the best quality of 'Kroska' and 'Miranda'. Pumpkins of this cultivars were the most suitable for being eaten raw. Fruits of other pumpkin cultivars showed significant differentiation of biochemical and electrochemical characteristics. The carotenoid content varied from 0.90 to 11.25 mg 100 g-1. The antioxidant activity, expressed as percentage of DPPH inhibition, varied from 12% for 'Zemciuzina' to 89% for 'Justynka'. The relationship between the measured quality parameters of fruits was also determined. A strong correlation between total carotenoids content and antioxidative activity was found.