EVOLUTION OF POLYPHENOLS AND FLAVONOIDS LEVELS IN LEAVES, MESOCARP AND KERNEL OF THREE JUGLANS REGIA L. CULTIVARS

Abstract

This paper studies polyphenols and flavonoids level evolution in Juglans regia L. leaves and mesocarp during the growing season, as well as compounds evolution in the walnut kernel for fully mature picked nuts, stored for eight months at room temperature. Both compounds, polyphenols and flavonoids were significantly influenced by cultivar, harvest moment, and, respectively, by the storage time. The highest content of polyphenols was found in ′Jupânești′ cultivar’s leaves, ′Vina′ cultivar’s kernel, and ′Franquette′ cv. mesocarp. Also, nut mesocarp and leaves samples harvested in July and nut kernel stored till next March contained maximum polyphenols levels. The highest flavonoid content was determined for ′Vina′ cultivar’s leaves, ′Franquette′ cultivar’s fruit mesocarp, ′Vina′’s kernel, leaves and mesocarp sampled in July and nut kernel stored until March. For the entire experiment, maximum polyphenols level was found in ′Jupânești′ cultivar’s leaves harvested in July. Flavonoids reached their highest level in case of ′Franquette′ kernel stored until March. The three studied cultivars: ′Jupânești′, ′Vina′ and ′Franquette′ can be valuable sources of phenolic compounds.