Influence of Processing Parameters on Phenolic Compounds and Color of Cabernet Sauvignon Red Wine Concentrates Obtained by Reverse Osmosis and Nanofiltration

Abstract

In this study, Cabernet Sauvignon red wine was subjected to reverse osmosis and nanofiltration processes at four different pressures (25, 35, 45, and 55 bar) and two temperature regimes (with and without cooling). The aim was to obtain concentrates with a higher content of phenolic compounds and antioxidant activity and to determine the influence of two membrane types (Alfa Laval RO98pHt M20 for reverse osmosis and NF M20 for nanofiltration) and different operating conditions on phenolics retention. Total polyphenol, flavonoid, monomeric anthocyanin contents, and antioxidant activity were determined spectrophotometrically. Flavan-3-ols and phenolic acids were analyzed on a high-performance liquid chromatography system and sample colour was measured by chromometer. The results showed that the increase in applied pressure and decrease in retentate temperature were favorable for higher phenolics retention. Retention of individual compounds depended on their chemical structure, membrane properties, membrane fouling, and operating conditions. Both types of membranes proved to be suitable for Cabernet Sauvignon red wine concentration. In all retentates, phenolic compounds content was higher than in the initial wine, but no visible color change (ΔE* < 1) was observed. The highest concentrations of phenolic compounds were detected in retentates obtained at 45 and 55 bar, especially with cooling.

Aroma Profile and Chemical Composition of Reverse Osmosis and Nanofiltration Concentrates of Red Wine Cabernet Sauvignon

“…Aroma compounds were analysed by gas chromatograph with mass spectrometer in obtained retentates and initial wine. In our previous study Cabernet Sauvignon was subjected to process of reverse osmosis and nanofiltration at different pressures and temperature regimes to determine the influence of RO and NF membranes on phenolics and colour compounds retention [28].…”

Concentration with Nanofiltration of Red Wine Cabernet Sauvignon Produced from Conventionally and Ecologically Grown Grapes: Effect on Phenolic Compounds and Antioxidant Activity

“…Several studies [2,[6][7][8] have reported that the phenolic profile of ecologically produced wine differs from the phenolic profile of conventionally produced ones, comparing the same grape variety. Phenolic compounds originate from the seeds and skins of grapes, and they are transferred into must during crushing, maceration or fermentation [9]. Therefore, the grape maturity and health, climate, the use of fertilizers or other adjuvants, harvest conditions and vinification techniques greatly affect the final concentrations of the mentioned compounds [10].…”

“…Compared to the reverse osmosis membranes, nanofiltration ones have slightly larger pore size that decreases the retention of bioactive compounds. However, at the same operating conditions, the permeate flux during nanofiltration is higher, the process duration time is shorter and membrane fouling is less severe than during the reverse osmosis process, which lowers the production cost [9]. The nanofiltration wine permeate contains mainly water and ethanol, but several low weight molecules can also pass through membranes, such as acetic and lactic acid, or some aroma compounds [18].…”

“…The nanofiltration wine permeate contains mainly water and ethanol, but several low weight molecules can also pass through membranes, such as acetic and lactic acid, or some aroma compounds [18]. Therefore, the nanofiltration process can be used for wine or must concentration [21,22], partial dealcoholisation of wine [23,24], acetic acid removal [25,26], aroma and phenolic contents correction [9,18]. In addition, nanofiltration can be used for the fractionation and extraction of polyphenols from grape pomace [27,28].…”

“…Such obtained retentate could be used as a drink or for further production of wine with a desired phenolic profile. The centre of interest of several previous studies included the influence of the nanofiltration process on phenolic compounds retention and antioxidant activity [9,22,23,30]. They all concluded that the nanofiltration process was applicable for wine concentration with moderate operation and investment costs.…”