Sitosterol Thermo‐oxidative Degradation Leads to the Formation of Dimers, Trimers and Oligomers: A Study Using Combined Size Exclusion Chromatography/Mass Spectrometry
Bibliographic record
Abstract
Phytosterols are recognized as functional food components with cholesterol reducing properties in humans. The formation of phytosterol oligomers as a result of the thermo-oxidative degradation of sitosterol is shown to occur. The existence of oligomers is demonstrated by size exclusion chromatography (SEC) and confirmed by combined SEC-atmospheric pressure chemical ionization mass spectrometry (SEC/APCI-MS). A speculative structure for the sitosterol dimer with 3,7' linkage is proposed consistent with data from tandem mass spectrometry and exact mass measurements. Higher molecular weight species arising from the formation of trimers or higher oligomers are seen in the mass spectra. Fragments of sitosterol formed by thermo-oxidative processes are also shown to oligomerize and their common structural characteristics are demonstrated by tandem mass spectrometry. The results presented provide evidence for the possible formation of oligomeric species involving sterols in addition to those known for acylglycerides in vegetable oils subjected to extreme oxidative stress such as in frying.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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 source (direct Gemma or distilled Codex), 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".