The formation of hydrogen sulfide during fermentation was followed by direct headspace sampling and quantification by gas chromatography with flame photometric detection. The formation of acetic acid was followed in the same fermentations but by sampling and capillary electrophoresis. Juice samples were analyzed for individual amino acids and correlations between these values, calculated free amino nitrogen (FAN) content and the formation of acetic acid and hydrogen sulfide were performed. The formation of acetic acid was very low (mean-0.09 mg/L, sd = 0.10 mg/L.) and could not be correlated with any of the compositional factors. The formation of hydrogen sulfide was variable (mean = 37 ug/L of juice, sd = 64 ug/L), ranging from none to 300 ug/L. The effect of yeast strain showed a wide variation in a single juice (mean = 226 ug/L, sd = 128 ug/L) with the cultures of Fermevin, Prisse du Mousse, Premier Cuvee being below the mean and those of Montrachet, Pasteur Champagne, Enoferm ICV-D46 and Lavin 7IB being above the mean. In the temperature series, the production of hydrogen sulfide increased from 68 ug/L at 15°C to 164 ug/L at 30°C and then fell to 56 ug/L at 35°C. Statistical analysis (principal component analysis) found the formation of sulfide during fermentation to be positively correlated (CC=+0.56) with the FAN content and (CC=+0.61) with the total nitrogen content. With respect to individual amino acids, alanine (CC=+0.72), glutamine (CC=+0.71), gamma-amino butyric acid (CC+0.68), glycine (CC=+0.66) and methionine (CC=+0.63) were the most strongly correlated with sulfide formation. These results with California juices are contrary to the widely-held belief that sulfide production is caused by low levels of free amino nitrogen.
/wp-content/uploads/2017/09/AFV-Header-Logo.png 0 0 AVF /wp-content/uploads/2017/09/AFV-Header-Logo.png AVF1995-11-22 17:45:102017-11-22 17:45:46Factors Affecting the Formation of Hydrogen Sulfide and Acetic Acid