Less-known Leaf Vegetables Grown in Slovak Republic Conditions: New Sources of Antioxidants

The goal of this study was to determine the content of bioactive substances (chlorophyll, carotenoids, vitamin C) in less-known leafy vegetable species, such as Chinese mustard (Brassica juncea (L.) Czern. Et Coss.), mibuna (Brassica rapa ssp. japonica Makino) and mizuna (Brassica rapa ssp. nipposinica (Bailey) Hanelt). Within study, two cultivars of Chinese mustard were tested, concretely cv. Ruby Streaks (purple leaves) and cv. Spicy Green (green leaves). The field experiment was realised on the land of Slovak University of Agriculture in Nitra in 2014 and 2015. The highest content of chlorophyll a and chlorophyll b, as the biologically most active chlorophyll types, was found in mibuna leaves. The Chinese mustard cv. Ruby Streaks was shown as the richest source of total carotenoids. The highest vitamin C content was found in leaves of Chinese mustard cv. Spicy Green. Compared to the typical leafy species like spinach, all tested less-known vegetable species were indicated as the comparable sources of chlorophyll. The content of other tested substances, such as carotenoids and vitamin C, was even higher than results presented in studies of several authors with spinach.