Phenolic compounds are dependent on cultivation conditions in face of UV-C radiation in ‘Concord’ grape juices (Vitis labrusca)

Grape juice is known as a relevant source of compounds with antioxidant potential, which are accumulated during grape growth and development. As these compounds come from specialized metabolism, postharvest stressors may increase the synthesis and accumulation of these metabolites. Thus, UV-C radiation (65.6 J m−2) was applied to ‘Concord’ grapes (from vineyards grown in conventional and organic systems), after harvest. The following dependent variables were analyzed: pH, total titratable acidity, total soluble solids, ratio, angle hue, L, a, b, ΔE, total phenolic compounds, total anthocyanins, malvidin, delphinidin, peonidin, cyanidin, epicatechin, quercetin, kaempferol, trans-resveratrol, and cis-resveratrol. The UV-C treatment did not interfere with the basic physicochemical composition but resulted in juices with a more intense color. Juice from grapes grown in an organic system and subjected to postharvest UV-C treatment had also an increase in the levels of phenolic compounds, which was not observed in juice from grapes grown in a conventional system and subjected to the same treatment. Thus, responses to postharvest UV-C radiation depend on cultivation conditions. [Display omitted] •Postharvest UV-C treatment induces bioactive compounds in grapes “Concord”.•Postharvest UV-C radiation is dependent on the grape cultivation system in the bioactive compounds synthesis.•Juices produced with grapes treated with UV-C, have high antioxidant potential regardless of the grapes cultivation system.