La variabilità del colore in vini rosati dell’Italia meridionale

Mannoproteins (MPs) are released from the yeast cell wall during alcoholic fermentation and aging on the lees, and influence aspects of wine quality such as haze formation and colour stability. Yet, as this is a slow process with microbiological and sensory risks, the exogenous addition of extracted MPs poses an efficient alternative. While Saccharomyces cerevisiae has long been studied as a prominent source for MPs extraction, their structure and composition greatly differ between yeast species. This may influence their behaviour in the wine matrix and subsequent impact on wine properties. However, although wine yeast species other than S. cerevisiae possibly present an untapped source of MPs, they are still ill-characterised in terms of chemical composition and influence on wine.

Most of the effects of ultrasound (US) result from the collapse of bubbles due to cavitation. The shockwave produced is associated with shear forces, along with high localised temperatures and pressures. However, the high-speed stream, radical species formation, and heat generated during sonication may also affect the stability of some enzymes and proteins, depending on their chemical structure. Recently, Ce-lotti et al. (2021) reported the effects of US on protein stability in wines. To investigate this further, the effect of temperature (40°C and 70°C; 60s), sonication (20 kHz and 100 % amplitude, for 20s and 60s, leading to the same temperatures as above, respectively), in combination with Aspergillopepsins I (AP-I) supplementation (100 μg/L), was studied on unstable protein concentration (TLPs and chitinases) using HPLC with an UV–Vis detector in a TLPs-supplemented model system and in an unstable white wine.

Acidity of grape berries is lowered due to climate changes (1), resulting in musts and wines with higher pHs. These higher pHs induce microbiological instability

Les pratiques de vinification et de dégustation du vin sont souvent perçues, à travers un discours marketing très puissant, sous l’angle d’une tradition millénaire qui perdure depuis le Moyen Âge. En Bourgogne, il est courant de rattacher les racines de ces pratiques à l’activité des institutions ecclésiastiques qui possédaient d

The addition of fungal chitosan in wine is allowed since 2009 to release some spoilage microorganisms such as Brettanomyces bruxellensis (OIV/OENO 338A/2009; EC 53/2011). This yeast is able to produce volatil phenols and is responsible of organoleptic deviations compromising quality and typicality of red wines [1]. Despite the fact that fungal chitosan is highly renewable, no toxic and non-allergenic, its use remains marginal because this treatment is relatively recent (compare to sulphites treatment) and information are contradictory between different studies described in literature. For all these reasons,