Qualitative characterisation of cultivated and wild edible plants: Mineral elements, phenols content and antioxidant capacity

Abstract

This study investigated the qualitative characteristics of several edible wild herbaceous species, including those most consumed in Foggia Province (southern Italy). Analysis of qualitative characteristics was performed for the edible parts of 11 wild species (Beta vulgaris L., Foeniculum vulgare Miller, Centaurea solstitialis L., Cichorium intybus L., Scolymus hispanicus L., Sonchus oleraceus L., Borago officinalis L., Diplotaxis erucoides L., Diplotaxis tenuifolia (L.) DC, Sinapis arvensis L., Portulaca oleracea L.) and three cultivated species (C. intybus, B. officinalis, D. tenuifolia). The plants were collected from areas in the Foggia countryside, and the edible part of each species was analysed for dry matter, protein, cation and anion contents as well as total phenols and antioxidant activities. Among the cations, calcium was the most differentiated among species, ranging 784 mg kg^–1 fresh weight (Fw) for B. vulgaris to 5886 mg kg^–1 Fw for S. hispanicus. The nitrate contents were also highly variable, from 75 mg kg^–1 Fw for C. intybus to 3874 mg kg^–1 Fw for D. tenuifolia. Total polyphenols ranged from 1054 mg gallic acid equivalents (GAE) mg kg^–1 Fw for C. solstitialis to 3664 mg GAE mg kg^–1 Fw for S. arvensis. Antioxidant activities ranged from 839 mg Trolox equivalents (TE) kg^–1 Fw for B. vulgaris to 5658 mg TE kg^–1 Fw for C. intybus. Significant differences were also noted between wild and cultivated plants in the qualitative parameters. Total polyphenols and antioxidant activity were higher in wild C. intybus and B. officinalis than in their cultivated counterparts. Multivariate analysis (cluster analysis and linear discriminant analysis) allowed integration of the ANOVA data to determine the qualitative characteristics of the wild species that contribute most to group differences. The results of the present study aims to improve current knowledge about edible wild species as vegetable sources in the Mediterranean diet.