Pyrethrum (Chrysanthemum cinerariifolium) Flowers’ Drying Conditions for Optimum Extractable Pyrethrins Content
Bibliographic record
Abstract
Pyrethrum flowers of the genus Chrysanthemum cinerariifolium are grown in Kenya by small scale farmers for extraction of pyrethrins, a natural insecticide’s active ingredient. Pyrethrins are classified in two groups, Pyrethrins I and II, and are degradable when exposed to air, moisture and high temperatures. The contents and ratio of Pyrethrins I:II determine the efficacy of the insecticide. Therefore, drying of the pyrethrum flowers should be optimized in order to attain maximum extractable pyrethrins content and optimum ratio. The aim of this research was to optimize the drying temperatures, time and moisture content of pyrethrum flowers. The flowers were harvested and dried at varying temperatures of 40, 50, 60 and 70 ºC to total dryness. Another set of flowers were harvested and dried in the oven at the same temperatures for a maximum period of 18 hrs. Moisture content was determined at each temperature, at intervals of one hour. The dried flowers were then ground into fine powder and extracted using Soxhlet extraction method with hexane. The extracts were refined and analyzed by Mercury reduction and High Performance Liquid Chromatographic methods. Pyrethrum flowers were found to achieve maximum moisture loss, at varying times and temperature with 70 ºC recording the shortest time of 18 hrs. The yield of pyrethrins obtained on drying the flowers to constant weight at 40 ºC was 0.90% while drying for 18 hrs yielded 0.79%. Extractable Pyrethrins II were found to reduce by 8.6% when the drying temperature was raised from 50 to 60 ºC and by 11.3% from 60 to 70 ºC. Extractable Pyrethrins I were found to reduce by 6% when the drying temperature was raised from 50 to 60 ºC and by 5% from 60 to 70 ºC. The total pyrethrins obtained from the flowers dried at 50 ºC were found to be 1.37% at 18 hrs and 1.44% to constant weight drying. The pyrethrins I:II ratio was found to vary over the temperature range 40-70OC.The optimum temperature and time for drying pyrethrum flowers was found to be 50 ºC for 21 hrs.
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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) | 0.001 | 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) | 0.000 | 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".