Production of white wine by Saccharomyces cerevisiae immobilized on grape pomace

Abstract

White wine was produced with Saccharomyces cerevisiae cells immobilized on grape pomace, by natural adsorption. The support, the main solid waste from the wine industry, consisted of the skins, seeds and stems. Immobilization was tested using different media, namely complex culture medium, raw grape must and diluted grape must. Grape pomace was revealed to be an appropriate support for yeast cell immobilization. Moreover, grape must was shown to be the most suitable medium as immobilized cells became adapted to the conditions in the subsequent alcoholic fermentation in the wine-making process. The wines produced, either with immobilized cells or with free cells, were subjected to chemical analysis by HPLC (ethanol, glycerol, sugars and organic acids) and by gas chromatography (major and minor volatile compounds); additionally, colour (CIELab) and sensory analysis were performed. The use of immobilized systems to conduct alcoholic fermentation in white wine production proved to be a more rapid and a more efficient process, especially when large amounts of SO 2 were present in the must. Furthermore, the final wines obtained with immobilized cells demonstrated improved sensory properties related to the larger amounts of ethanol and volatile compounds produced. The more intense colour of these wines could be a drawback, which could be hindered by the reutilization of the biocatalyst in successive fermentations.

Production of blueberry wine and volatile characterization of young and bottle‐aging beverages

“…Methanol was also found in blueberry wine at concentrations higher than those typically found in wine (approximately ester production is the result of hydrolysis reactions catalyzed by esterases, lipases, and alcohol acyl transferases (Costello, Siebert, Solomon, & Bartowsky, 2013). Ethyl acetate and ethyl lactate were the two esters found to have high volatile levels, and their concentrations were similar to those found in wines (Bartowsky & Pretorius, 2009;Genisheva, Macedo, Mussatto, Teixeira, & Oliveira, 2012).…”

“…Red wines made by skin contact fermentation in the presence of stems typically contain high levels of methanol, reflecting the variation in skin contact times(Hodson, Wilkes, Azevedo, & Battaglene, 2017). Ethyl acetate and ethyl lactate were the two esters found to have high volatile levels, and their concentrations were similar to those found in wines(Bartowsky & Pretorius, 2009;Genisheva, Macedo, Mussatto, Teixeira, & Oliveira, 2012).The concentrations of acetaldehyde, ethyl acetate, and 1-propanol were significantly higher in MSF wines than in those obtained under laboratory conditions, while ethyl lactate was lower in the former. These limits are fixed in the International Code of Oenological Practices (Code) or in the Recueil of International Methods of Analysis for Wines and Musts, limits that are not exceeded in the wines obtained in this study.…”

Aroma formation by immobilized yeast cells in fermentation processes

“…isoamyl acetate, ethyl hexanoate, E‐3 ‐hexen‐1‐ol, 2‐phenylethyl acetate β ‐damascenone, etc.) and a higher colour intensity, compared with the wines produced with the free cells (Genisheva et al, ).…”

“…A different approach includes the use of wine industry wastes, such as grape skins, stems or pomace, as well as raisins and grape berries. Mallouchos et al (), who investigated grape skins as a natural support for yeast immobilization, reported increased productivity and a positive impact on wine aroma, while in another study, grape pomace, the solid waste resulting from grape pressing, and grape stems were studied as a means of yeast cell immobilization by natural adsorption for white wine production (Genisheva et al, , , ). Freeze‐dried grape berries from two varieties were also assessed as yeast support matrices for the fermentation of honey.…”

“…Examples of supports used are starchy materials such as barley (Kandylis et al, ), corn grains (Kandylis et al, ), wheat (Kandylis et al, , ), corn starch gel (Kandylis et al, ), potatoes (Kandylis and Koutinas, ), gluten pellets (Bardi et al, ), fruit pieces, e.g. apple, quince, pear, papaya (Kourkoutas et al, ; Maragatham and Panneerselvam, ), delignified cellulosic materials (Koutinas et al, ), grape pomace (Genisheva et al, ), brewer's spent grains (Mallouchos et al, ; Kopsahelis et al, ), sugar cane pieces (Reddy et al, ) and cork pieces (Tsakiris et al, ). The advantages of immobilization technology in wine‐making become obvious through some of the most recent examples of research.…”