Effects of the pre‐fermentative addition of chitosan on the nitrogenous fraction and the secondary fermentation products of SO₂‐free red wines

Abstract

BACKGROUNDDifferent red winemaking were carried out to evaluate the effects of the prefermentative addition of chitosan, as an alternative to the use of SO2, on the secondary products of alcoholic fermentation, yeast available nitrogen (YAN), biogenic amines and ethyl carbamate.RESULTSThe wines made with chitosan presented higher total acidity and higher content of tartaric and succinic acids than those made only with SO2. The use of chitosan in winemaking resulted in wines with higher glycerol and diacetyl content without increasing the concentration of ethanol, acetic acid, acetaldehyde or butanediol. YAN was lower in wines made with chitosan, which may mean an advantage for the microbial stability of the wines. Furthermore, the use of chitosan at the beginning of alcoholic fermentation did not increase the concentration of biogenic amines or the formation of ethyl carbamate in SO2‐free red wines.CONCLUSIONThe total or partial substitution of SO2 for chitosan at the beginning of the alcoholic fermentation gives rise to quality red wines without negatively affecting their nitrogen fraction or their very important secondary fermentation products such as acetic acid or acetaldehyde. © 2020 Society of Chemical Industry

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“…It is of note that all the treated wines presented a YAN concentration higher than that required to prevent standstills in fermentations. 45 Our results were in consonance with those observed by Marchante et al, 31 who evaluated the use of chitosan as an alternative to SO 2 in winemaking. The authors observed that the presence SD, standard deviation (n = 3).…”

“…However, the pre‐fermentative addition of the different compounds or extracts modified the concentration of some wine components. Differences were found in dry extract and glycerol, which may be related to glycerol's capacity to readjust the osmotic gradient across the cell membrane so that cellular functions remained under osmotic stress conditions such as after the pre‐fermentative addition of solutes (i.e., GSH and ST99), as described for chitosan‐treated red wines 31 …”

“…The SO 2 wines showed the highest concentrations of GABA, ⊎-alanine, cysteine and leucine. Marchante et al 31 also described an effect of chitosan on the GABA concentration in wine.…”

“…Other authors compared wines treated with SO 2 , lysozyme and dimethyl decarbonate, reporting higher values of BAs for SO 2 wines and putrescine values similar to our data. 41 In addition, Marchante et al 31 also identified putrescine in wines elaborated with chitosan and three BAs (histamine, tyramine and phenylethylamine); however, the authors did not find significant differences between treatments in young red wines.…”

“…Differences were found in dry extract and glycerol, which may be related to glycerol's capacity to readjust the osmotic gradient across the cell membrane so that cellular functions remained under osmotic stress conditions such as after the prefermentative addition of solutes (i.e., GSH and ST99), as described for chitosan-treated red wines. 31 Organic acids presented suitable values for white wines. Only tartaric acid showed differences among treatments (Table 1), which is somehow related to the treatments.…”