Wine Lees: Traditional and Potential Innovative Techniques for their Exploitation in Winemaking

Aging of wine on lees enhances the sensorial characteristics of wine. Only a small part of the lees produced in winemaking are used in traditional aging. Most are collected and then distilled or processed to obtain low quality wine. For these reasons, lees are currently an undervalued by-product of winemaking. A new technique was tested on an industrial scale to provide wine from lees of different origin. After racking, the lees were collected in an innovative steel system and processed by cycles of mixing in controlled condition of temperature and micro-oxygenation. The processing technique contributed to improving the chemical characteristics of wine from the lees. Wines obtained from the treated lees were characterized by color intensity, total polyphenols and total polysaccharides significantly higher compared to those from not treated lees, used as control. The addition of small quantities of wine from lees to a base wine led to a significant decrease of astringency and increase in body, overall aroma, olfactory intensity, and sweet sensation. The obtained results indicate that the proposed method could be an effective tool to exploit lees on a winery scale

A New Technique for Exploitation of Wine Lees

Abstract The possibility of obtaining high quality wine from lees could increase value added for farm productions. A new technique introduced on an industrial scale to provide wine from lees of different origin is presented. After racking, the lees are collected in an innovative steel system and processed in controlled conditions of temperature, micro-oxigenation and cycles of remixing. During the treatment, an increase of color intensity, total polyphenols and total polysaccharides of wine from the lees was detected while the hue was stable. The obtained results indicate that the proposed method could be an effective tool for exploitation of the lees on winery scale. The new technology strongly reduced the time necessary to reach positive oenological objectives

Characterisation of Extracts Obtained from Unripe Grapes and Evaluation of Their Potential Protective Effects against Oxidation of Wine Colour in Comparison with Different Oenological Products

Unripe grapes (UGs) are a waste product of vine cultivation rich in natural antioxidants. These antioxidants could be used in winemaking as alternatives to SO(2). Three extracts were obtained by maceration from Viognier, Merlot and Sangiovese UGs. The composition and antioxidant activity of the UG extracts were studied in model solutions at different pH levels. The capacity of the UG extracts to protect wine colour was evaluated in accelerated oxidation tests and small-scale trials on both red and white wines during ageing in comparison with sulphur dioxide, ascorbic acid and commercial tannins. The Viognier and Merlot extracts were rich in phenolic acids while the Sangiovese extract was rich in flavonoids. The antioxidant activity of the extracts and commercial tannins was influenced by the pH. In the oxidation tests, the extracts and commercial products showed different wine colour protection capacities in function of the type of wine. During ageing, the white wine with the added Viognier UG extract showed the lowest level of colour oxidation. The colour of the red wine with the UG extract evolved similarly to wine with SO(2) and commercial tannins. The obtained results indicated that natural and healthy UG extracts could be an interesting substitute for SO(2) during wine ageing

Le proteine dei vini rossi: risultati preliminari

Lo studio delle proteine dei vini rossi \ue8 parte del progetto GO Vintegro che ha come obiettivo quello di mettere a punto un test efficiente per la valutazione della stabilit\ue0 colloidale. Recentemente, \ue8 stata evidenziata nei vini rossi la presenza di aggregati proteine-fenoli solubili ed \ue8 stato proposto un nuovo modello per la struttura colloidale di questi vini nel quale: a) sub-aggregati costituiti da fenoli e proteine legati covalentemente interagiscono con molecole polisaccaridiche tramite forze non-covalenti; b) aggregati ai quali partecipano solo fenoli e polisaccaridi. Sono stati analizzati 24 vini di diversa tipologia: Cabernet franc, Cabernet sauvignon, Cabernet franc & sauvignon, Merlot, Sangiovese, Sangiovese & Merlot, Syrah. I vini sono stati analizzati in 3 differenti fasi della vinificazione (pre-stabilizzazione, pre-imbottigliamento, imbottigliamento) per i seguenti parametri: proteine totali, polifenoli totali, test di stabilit\ue0 a caldo, profilo elettroforetico, profilo fenolico. I vini analizzati mostravano differenze nel contenuto in polifenoli totali e nella stabilit\ue0 valutata a caldo in funzione della tipologia. Tutti i vini contenevano proteine in concentrazione variabile fra 1,8 e 29,3 mg/L di vino. Le analisi elettroforetiche fino ad ora eseguite hanno rivelato la presenza di bande a differente peso molecolare non comparabili a quelle a pi\uf9 basso peso molecolare che normalmente si possono osservare nei vini bianchi. La concentrazione proteica era positivamente correlata (p=0,000) con alcuni parametri del corredo fenolico come, ad esempio, il colore, gli antociani liberi e totali, i fenoli totali e con l\u2019alcol indicando un possibile effetto della maturit\ue0 dell\u2019uva sulla concentrazione delle proteine nel vino