ORIGINAL PAPER Partial dealcoholisation of red wines by membrane contactor technique: influence on colour, phenolic compounds and saliva precipitation index Angelita Gambuti • Alessandra Rinaldi • Maria Tiziana Lisanti • Rita Pessina • Luigi Moio Received: 3 February 2011 / Revised: 25 July 2011 / Accepted: 30 July 2011 / Published online: 20 August 2011 Ó Springer-Verlag 2011 Abstract In this study, red wines from different grape varieties (Merlot, Aglianico and Piedirosso) and containing different alcoholic level (from 13.67 to 15.46% v/v) were treated to diminish the alcoholic percentage of 2, 3 and 5% v/v by a polypropylene hollow fibre membrane contactor apparatus. The wines were analysed before and after partial dealcoholisation. Colour indexes and phenolics were ana- lysed by spectrophotometric methods and HPLC. Wine astringency was evaluated by an astringency index based on the ability of treated wines to precipitate salivary proteins (SPI, Saliva Precipitation Index). For all the levels of deal- coholisation studied, changes in chromatic characteristics, Folin–Ciocalteu index and vanillin reactive flavans were below the methodological errors of the analyses. A loss of malvidin 3-monoglucoside was detected after the dealco- holisation process. Decreasing the ethanol content of wines caused an increase in SPI values. Keywords Partial dealcoholisation Á Red wine Á Membrane contactor Á Phenolic compounds Á Saliva precipitation index (SPI) Introduction Alcohol levels in wine have been increasing over the last decades. This is due to the tendency for vine growers to plant grape varieties that produce more sugar, as well as climate changes and improvements in viticulture and in winemaking techniques. Today, the level of alcohol in wine is an issue as consumers have become more health- conscious. For this reason, the worldwide demand for less alcoholic wines, as well as the treatments in wine industry aimed to reduce ethanol level, is growing. In view of this exigency, the EU regulation permits up to a 2% adjustment. However, in some cases, as during very warm vintages, there is the necessity of reducing the ethanol content of wine more than 2%. Several techniques have been developed to partially reduce alcohol content in wines, such as reverse osmosis [1], vacuum membrane distillation [2], pervaporation [3] and spinning cone column [4]. The goal of winemaking industry is to find a method able to reduce alcohol without lowering the concentration of other compounds involved in wine quality. Membrane contactors are among the most used systems in the industry to decrease the ethanol content of 1–5%. Until now, the effect of this treatment has been mainly evaluated for sensory quality [5] and for aroma volatile compounds in model wine solution [6]. In spite of the importance of phenolic compounds for wine colour, mouthfeel sensations, ageing behaviour and their beneficial effects on human health, no data were reported on the effect of partial dealcoholisation by membrane contactors on wine phenolics and wine chromatic characteristics. An interesting result on the effect of partial dealcoholi- sation by reverse osmosis on mouthfeel sensations was reported: astringency, in several cases, increased [7]. As this sensation is mainly due to salivary proteins–polyphenols interactions [8], this effect may be ascribed to a change in phenolic composition of wine and/or to an effect exercised by ethanol on the phenomena that origin astringency. Until now, the effect of dealcoholisation by membrane process on A. Gambuti (&) Á A. Rinaldi Á M. T. Lisanti Á R. Pessina Á L. Moio Dipartimento di Scienza degli Alimenti, Facolta ` di Agraria, Universita ` di Napoli Federico II, Portici, Italy e-mail: angelita.gambuti@unina.it A. Gambuti Á A. Rinaldi Á M. T. Lisanti Á R. Pessina Á L. Moio Corso di Laurea in Viticoltura ed Enologia, Via Tuoro Cappuccini No. 6, 83100 Avellino, Italy 123 Eur Food Res Technol (2011) 233:647–655 DOI 10.1007/s00217-011-1553-2