Formation and Retention of Free H<sub>2</sub>S and of Free Volatile Thiols during Beer Fermentation

Brenner, M. W.; Khan, Anzar; Bernstein, Leo

doi:10.1080/00960845.1975.12006564

Cited by 2 publications

(1 citation statement)

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“…It is generally agreed that the major portion of H 2 S arises as an intermediate in the biosynthesis of sulfur-containing amino acids by yeast during fermentation , . Yeast strain − , must turbidity , availability of fermentation nutrients , , and presence of metal ions can affect the amount of H 2 S produced during fermentation. Other low molecular weight VSCs, such as mercaptans, sulfides, and disulfides, have been also identified in wines.…”

Section: Introductionmentioning

confidence: 99%

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

Ugliano

Fedrizzi

Siebert

et al. 2009

J. Agric. Food Chem.

100

107

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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.

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Section: Introductionmentioning

confidence: 99%

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

Ugliano

Fedrizzi

Siebert

et al. 2009

J. Agric. Food Chem.

100

107

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Smart Detection of Faults in Beers Using Near-Infrared Spectroscopy, a Low-Cost Electronic Nose and Artificial Intelligence

2021

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Early detection of beer faults is an important assessment in the brewing process to secure a high-quality product and consumer acceptability. This study proposed an integrated AI system for smart detection of beer faults based on the comparison of near-infrared spectroscopy (NIR) and a newly developed electronic nose (e-nose) using machine learning modelling. For these purposes, a commercial larger beer was used as a base prototype, which was spiked with 18 common beer faults plus the control aroma. The 19 aroma profiles were used as targets for classification machine learning (ML) modelling. Four different ML models were developed; Models 1 (M1) and M2 based on NIR (100 inputs from 1596–2396 nm) and M3 and M4 based on the e-nose (nine sensor readings as inputs) and 19 aroma profiles as targets for all models. A customized code tested 17 artificial neural network (ANN) algorithms automatically testing performance and neuron trimming. Results showed that the Bayesian regularization algorithm was the most adequate for classification rendering precisions of M1 = 98.9%, M2 = 98.3%, M3 = 96.8%, and M4 = 96.2% without statistical signs of under- or overfitting. The proposed system can be added to robotic pourers and the brewing process at low cost, which can benefit craft and larger brewing companies.

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Formation and Retention of Free H₂S and of Free Volatile Thiols during Beer Fermentation

Cited by 2 publications

References 1 publication

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

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

Smart Detection of Faults in Beers Using Near-Infrared Spectroscopy, a Low-Cost Electronic Nose and Artificial Intelligence

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Formation and Retention of Free H2S and of Free Volatile Thiols during Beer Fermentation

Cited by 2 publications

References 1 publication

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

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

Smart Detection of Faults in Beers Using Near-Infrared Spectroscopy, a Low-Cost Electronic Nose and Artificial Intelligence

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Formation and Retention of Free H₂S and of Free Volatile Thiols during Beer Fermentation