Low-pressure continuous dynamic extraction from oak chips combined with passive micro-oxygenation to tune red wine properties

Static infusion of oak chips in wine is a common practice during wine ageing, aimed at improving sensory properties and stability of wines. The wine/chips contact required to reach the desired effect can last several weeks or months. A low-pressure continuous dynamic (LPCD) extractor in which a closed-circle, low-pressure continuous flow of wine passes through an extraction cell filled with chips, was evaluated as a tool to tune red wine properties in few hours. The aim of this work was to evaluate the effect of the use of a LPCD extractor the effect on color, volatile compounds and sensory properties of a Primitivo wine, as well as to assess the combined effect of LPCD extractor, passive microxygenation through polyethylenetereftalate (PET) containers and exogenous tannins. Their combined effect caused a significant increase of stabilized pigments was observed, without compromising the aroma profile. LPCD extraction, passive micro-oxygenation through plastic materials and enological tannins can be considered as a low-cost, and potentially low-impact, integrated technological platform suitable to tune wine sensory properties and stability, when either traditional approaches (such as barrel aging) or other assisted extraction technologies are not applicable or preferred, even in small wineries

Carrageenan as possible stabilizer of calcium tartrate in wine

Calcium-induced instability has recently become a major issue in bottled wines, as an effect of compositional changes induced by global warming. Up to date, few tools are available for calcium stabilization purposes. The present research was aimed at evaluating the potential activity of carrageenans (mixture of ι- and κ-) as stabilizers of calcium tartrate (CaT) in white and rosé wines. Four white and two rosé wines, with differing CaT and potassium bitartrate (KHT) stability were characterized. The addition of carrageenans improved both CaT and KHT stability, determining a decrease of saturation temperatures of both CaT and KHT (TsatCaT and TsatKHT). Sodium bentonite was used to evaluate possible synergic effect. The addition of carrageenans (0.75 g L−1) followed by sodium bentonite (0.5 g L−1) allowed to stabilize CaT in all wines, with a TsatCa2+ mean value of 6.7 °C; all samples also reached protein stability, with the exception of one sample that slightly exceeded the conventional threshold of protein stability. As a plus, KHT stability was also improved. The mini-contact test with seeds of micronized CaT, DLS analysis and FTIR spectra confirmed that CaT stability was due to Ca2+ ions colloidal stabilization rather than removal; that the mechanism of stabilization could include ternary complexes involving carrageenan, calcium ions and proteins; and that the synergic effect of bentonite could be attributed to competitive adsorption of proteins, with consequent adsorption of larger amounts of Ca2+ ions by carrageenan

Low-pressure continuous dynamic extraction from oak chips combined with passive micro-oxygenation to tune red wine properties

Static infusion of oak chips in wine is a common practice during wine ageing, aimed at improving sensory properties and stability of wines. The wine/chips contact required to reach the desired effect can last several weeks or months. A low-pressure continuous dynamic (LPCD) extractor in which a closed-circle, low-pressure continuous flow of wine passes through an extraction cell filled with chips, was evaluated as a tool to tune red wine properties in few hours. The aim of this work was to evaluate the effect of the use of a LPCD extractor the effect on color, volatile compounds and sensory properties of a Primitivo wine, as well as to assess the combined effect of LPCD extractor, passive microxygenation through polyethylenetereftalate (PET) containers and exogenous tannins.Their combined effect caused a significant increase of stabilized pigments was observed, without compromising the aroma profile.LPCD extraction, passive micro-oxygenation through plastic materials and enological tannins can be considered as a low-cost, and potentially low-impact, integrated technological platform suitable to tune wine sensory properties and stability, when either traditional approaches (such as barrel aging) or other assisted extraction technologies are not applicable or preferred, even in small wineries

Influence of prolonged maceration on phenolic compounds, volatile profile and sensory properties of wines from Minutolo and Verdeca, two Apulian white grape varieties

Prolonged maceration was applied to two Apulian white grape cultivars, Minutolo and Verdeca. The impact of prolonged maceration (up to six months) on the quality of the wines was evaluated through characterization of phenolic, volatile and sensory profiles. Macerated wines presented a peak of extraction after 4 months, followed by a decrease probably due to precipitation/reabsorption. Extraction of seed phenols occurred during longer maceration times. Volatile profile was also modified, showing a different behavior at different maceration times. Oxidation and aging compounds appeared during maceration, that are unusual for traditional white wines. Furthermore, maceration successfully enhanced varietal identity of Minutolo. The terpene profile of Minutolo wines changed during maceration, with a maximum of terpenols after 1 month of maceration, while longer maceration added a pattern of oxidized terpenes. Sensory analysis highlighted clearly distinct profiles of wines, according to both cultivar and maceration time. A good attitude was observed of both varieties to undergo maceration. In particular, Verdeca appeared suitable for longer maceration times, with flowery, citrus and apricot notes after 4 months, while enhanced apricot notes were perceived after 6 months. On the other hand, Minutolo wine after 6 months of maceration was characterized by a marked astringency and peach flavor