Microstructure and oenological potential of vine-shoot chips as affected by chips pre-treatments and addition strategy

This work aims at evaluating the effect of vine-shoot chips pretreatment and their addition strategy on the final chemical composition of Aglianico and Nero di Troia wines. Primitivo vine-shoot chips were subjected to three pretreatments (toasted, boiled and toasted, steam-treated and toasted) and then added to the wines either during maceration or aging phases. Microstructural analyses showed that toasting caused the formation and propagation of cracks in chips, increasing their surface area; while boiling and steam-treatment induced the collapsing of the chips inner structure, limiting wine-chip exchanges. Toasted chips in maceration reduced the titratable acidity, total phenolic and ethanol contents, flavonoids concentration and increased macro and microelement concentration of the wine. When vine-shoot chips were added during aging, S, P K, Cl, Fe, quercetin, color intensity, vanillin-reactive flavans, antioxidant activity and anthocyanins reduced, and no effect of the chip pretreatment was observed.