Impact of thiamine and pyridoxine on alcoholic fermentations of synthetic grape juice
by Huajing Xing, M.S.
Washington State University
Chair: Charles G. Edwards
Sluggish fermentation and H2S production are serious problems found in the wine
industry since they are directly related to wine quality and economic issues. There are
several factors that can cause these problems, such as nitrogen and vitamin deficiencies.
In this study, the effects of thiamine (vitamin B1) and pyridoxine (vitamin B6) on
alcoholic fermentation rates and hydrogen sulfide (H2S) production were studied. Using a
synthetic grape juice base, three fermentations were conducted: (1) a 2 × 3 factorial
design with nitrogen (60 and 250 mg/L) and thiamine (0, 0.2, and 0.5 mg/L) as variables
with a sufficient concentration of pyridoxine (2 mg/L), (2) a 2 × 3 factorial design with
nitrogen (60 and 250 mg/L) and pyridoxine (0, 0.25, and 0.5 mg/L) as variables with a
sufficient concentration of thiamine (0.5 mg/L), and (3) a 3 × 3 factorial design for
comparing the effects of thiamine (0, 0.2, and 0.5 mg/L) and pyridoxine (0, 0.25, and 0.5
mg/L) at the low concentration of nitrogen (60 mg/L). Fermentations were conducted
with Saccharomyces cerevisiae UCD 522 at 22oC.
Thiamine, pyridoxine, nitrogen and their interactions were found to affect
fermentation rate and H2S production. At low levels of thiamine and pyridoxine, yeast
exhibited slower fermentation rate regardless of nitrogen concentration, which indicated
that thiamine and pyridoxine deficiencies may cause sluggish fermentations. Hydrogen
sulfide production was significantly different (p ? 0.001) at different concentrations of
thiamine and pyridoxine. Furthermore, interactions between thiamine, pyridoxine and
nitrogen also highly affected hydrogen sulfide production. Sensory evaluation methods
were applied to the synthetic wine samples fermented at different thiamine, pyridoxine
and nitrogen concentration combinations and hydrogen sulfide was found to be
significant different in aroma attribute rating.
By adjusting thiamine, pyridoxine and nitrogen concentrations in grape juice,
sluggish fermentation and excessive hydrogen sulfide production can be reduced.
School:Washington State University
School Location:USA - Washington
Source Type:Master's Thesis
Keywords:food fermentation artificial foods
Date of Publication: