Effects of Distillation Time on the Pinus ponderosa Essential Oil Yield, Composition, and Antioxidant Activity
Bibliographic record
Abstract
This study evaluated the effect of distillation time (DT; 1.25, 2.5, 5, 10, 20, 40, 80, 160, 240, and 360 min) on essential oil yield, composition, and the antioxidant activity of ponderosa pine essential oil. Pine essential oil yield increased with length of the DT and reached maximum at 160 min DT. The major oil constituents were alpha-pinene and beta-pinene, ranging from 17% to 40% and from 21% to 29%, respectively, of the total oil. Overall, the concentration of alpha-pinene and beta-pinene was high at the initial DT (5–20 min) and decreased with increasing DT. The concentration of myrcene (range, 0.9% to 1.5%) was lowest at 5 min DT, then increased at 10 min DT, and did not change with longer DT. Overall, the concentrations of most other constituents (delta-3-carene, limonene, cis-ocimene, alpha-terpinyl acetate, germacrene-D, alpha-muurolene, gamma-cadinene, delta-cadinene, and germacrene-D-4-ol) were low at the initial DT and increased with increasing DT. Total yields (a function of oil yield and the concentration of individual constituents) of all constituents were generally the lowest at 5 min DT, increased with increasing DT, and reached maximum at 160 min DT. The antioxidant capacity of the pine oil in this study varied between 7.0 and 14.5 μmole Trolox/g and was unaffected by DT. This study demonstrated that DT can significantly modify the essential oil yield and composition of ponderosa pine needles. Furthermore, DT could be used to obtain pine oil with targeted chemical profiles. This report can also be used as a reference point for comparing literature reports, in which different DTs are used to extract essential oil of ponderosa pine.
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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) | 0.001 | 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 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".