Acetaldehyde in wines and its metabolism by wine lactic acid bacteria
Bibliographic record
Abstract
Acetaldehyde is the most important wine carbonyl and is mainly formed by yeast during alcoholic fermentation (AF) or by oxidation of ethanol. It is a small and highly reactive molecule that has chemical, sensory and microbiological significance. In most table wines, the acetaldehyde aroma is undesired and chemically bound to SO2. Besides masking the acetaldehyde aroma, SO2 has antimicrobial and antioxidant roles, and bound SO 2 is less active in these functions. Thus, wines with acetaldehyde require more SO2, which may be of concern for health reasons. For this thesis, acetaldehyde concentrations in Ontario wines were studied, as well as the metabolism of free and SO2-bound acetaldehyde by wine lactic acid bacteria (LAB) and its effect on growth. Red and white wines had averages of 20 and 40 mg l-1, respectively, and the lowest and highest overall values were 1 and 232 mg l-1. Acetaldehyde concentrations were not correlated with wine quality. Acetaldehyde is degraded by most LAB simultaneously with malic acid across wine pH levels. Previous microbial adaptation to high acetaldehyde concentrations led to modified degradation kinetics and higher degradation rates, which may be useful for the specific removal of acetaldehyde in wines, which would not benefit from acid reduction. There was no stimulation of bacterial growth by acetaldehyde and SO2 -bound acetaldehyde inhibited bacteria.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".