Effect of Nitrogen Supplementation and Saccharomyces Species on Hydrogen Sulfide and Other Volatile Sulfur Compounds in Shiraz Fermentation and Wine

Abstract

A Shiraz must with low yeast assimilable nitrogen (YAN) was supplemented with two increasing concentrations of diammonium phosphate (DAP) and fermented with one Saccharomyces cerevisiae and one Saccharomyces bayanus strain, with maceration on grape skins. Hydrogen sulfide (H(2)S) was monitored throughout fermentation, and a total of 16 volatile sulfur compounds (VSCs) were quantified in the finished wines. For the S. cerevisiae yeast strain, addition of DAP to a final YAN of 250 or 400 mg/L resulted in an increased formation of H(2)S compared to nonsupplemented fermentations (100 mg/L YAN). For this yeast, DAP-supplemented fermentations also showed prolonged formation of H(2)S into the later stage of fermentation, which was associated with increased H(2)S in the final wines. The S. bayanus strain showed a different H(2)S production profile, in which production was inversely correlated to initial YAN. No correlation was found between total H(2)S produced by either yeast during fermentation and H(2)S concentration in the final wines. For both yeasts, DAP supplementation yielded higher concentrations of organic VSCs in the finished wines, including sulfides, disulfides, mercaptans, and mercaptoesters. PCA analysis indicated that nitrogen supplementation before fermentation determined a much clearer distinction between the VSC profiles of the two yeasts compared to nonsupplemented fermentations. These results raise questions concerning the widespread use of DAP in the management of low YAN fermentations with respect to the formation of reductive characters in wine.

Occurrence of hydrogen sulfide in wine and in fermentation: influence of yeast strain and supplementation of yeast available nitrogen

“…Chemical and microbiological analyses YAN was calculated as the sum of ammonia-derived nitrogen and FAN, and therefore did not include proline [25]. The fermentation progress was monitored by daily analysis of residual sugar by means of an enzymatic kit.…”

“…Based on the observation that a negative correlation exists between naturally occurring nitrogen in the juice and total H 2 S formed during fermentation [28], one commonly adopted strategy to limit formation of H 2 S in wine fermentations is to provide adequate yeast assimilable nitrogen (YAN) to ensure sufficient availability of the amino acid precursors [reviewed in 1]. However, recent data have suggested that the addition of YAN to wine fermentations not only does not reduce H 2 S formation, but in some cases even appears to exacerbate the problem [14,25,26,29]. The observation, reported by the same authors, that this effect is also strain-dependent, suggests that interactions between YAN and the genetic background of individual yeasts are a key factor in determining the amount of H 2 S formed during fermentation.…”

Persistence of Elemental Sulfur Spray Residue on Grapes during Ripening and Vinification

“…Thus, under these particular fermentation conditions, results here agree with previous reports that S 0 residues above 1 μg/g can increase H 2 S production (Thoukis andStern 1962, Wenzel et al 1980). However, at low S 0 concentrations, other factors such as juice nutrient status (Ugliano et al 2009) likely have a larger role in explaining differences in H 2 S production. Additionally, yeast strain will affect not only H 2 S production, but also the conversion efficiency of S 0 to H 2 S (Acree et al 1972).…”

“…The S 0 concentration necessary to cause problems is not well agreed upon, in part because H 2 S production is affected by factors other than S 0 concentration. H 2 S is produced during fermentation as a byproduct of amino acid synthesis during normal yeast (Saccharomyces cerevisiae) metabolism (Jiranek et al 1995), and this pathway can lead to differences in H 2 S production in the absence of S 0 residues, related to differences in juice nutrient status (Ugliano et al 2009), must turbidity, yeast strain (Rankine 1963), and fermentation temperature (Schutz and Kunkee 1977).…”

Impact of different vinification techniques on the formation of reductive notes inVitis viniferacv. Vernatsch

“…However, recent works show there are other molecules than H 2 S, which can enhance the appearance of reductive notes in wines [14]. Rauhut and Kürbel [15,16] report that wines with sulfur aroma defects had increased concentrations of methanethiol (MeSH), ethanethiol (EtSH), dimethyl disulfide (DMDS), methyl ethyl disulfide (MeSSEt), diethyl disulfide (DEDS), thioacetic acid-S-methyl ester (MeSAc) and thioacetic acid-S-ethyl ester (EtSAc) as well as other known and unknown S-compounds.…”