Thesis
Impact of nitrogen source on yeast metabolism and H₂S formation
Washington State University
Master of Science (MS), Washington State University
2011
Handle:
https://hdl.handle.net/2376/101922
Abstract
The impact of using aspartic acid and glutamine as nitrogen supplements for alcoholic fermentations by Saccharomyces was studied. Synthetic grape juice media and commercially-prepared grape juices were supplemented with diammonium phosphate, aspartic acid, or glutamine to increase yeast assimilable nitrogen concentrations to 250 mg N/L prior to fermentation. Two yeast strains, UCD522 (Montrachet) and EC1118 (Prise de Mousse), were inoculated at 105 CFU/mL and fermentations were monitored for sugar consumption, H2S production, and utilization of amino acids. In general, unsupplemented musts fermented slower than supplemented ones, produced significantly more hydrogen sulfide (H2S), and contained lower amounts of residual amino acids. Among the various supplemented treatments, fermentation rates, H2S production, and amino acid utilization varied. Those fermentations supplemented with aspartic acid were generally slower and sometimes did not achieve dryness. In contrast, glutamine additions yielded fermentation rates and H2S production equivalent or superior to aspartic acid or DAP supplemented treatments. Nitrogen supplementation did not significantly affect aroma after fermentation. Based on these results, the use of glutamine appears promising as an alternative nitrogen supplement for wine production.
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Details
- Title
- Impact of nitrogen source on yeast metabolism and H₂S formation
- Creators
- J. Quinton Sturgeon
- Contributors
- Charles G. Edwards (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Food Science, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900525041801842
- Language
- English
- Resource Type
- Thesis