Rwandan Coffee arabica has caffeine increasing with altitude, but undetectable phytomelatonin
Bibliographic record
Abstract
• Rwandan C. arabica at high altitude had more caffeine than at lower altitudes. • TLC, GC–MS, and HP-LC detected no melatonin in Rwandan C. arabica . • Melatonin products from Belgium failed the quality assessment test. Altitude affects plants’ constituents. The presence of caffeine and melatonin in many plants, including C. arabica, has been widely reported. However, a possible variation of their quantity in Rwandan C. arabica samples across different altitudinal locations is not yet known. This study sought to provide this information. C. arabica samples from Kayonza, Ruhango, Gakenke, Gatsibo, Nyagatare, and Karongi districts, covering different altitude ranges in Rwanda, were obtained from the National Agriculture Export Development Board (NAEB). Analytical techniques like Thin-Layer Chromatography (TLC), High-Performance Liquid Chromatography (HPLC), and Gas Chromatography-Mass Spectrometry (GC–MS) were used. C. arabica samples from higher altitudes yielded higher caffeine content, while instant coffee samples showed a broad caffeine range. However, all the techniques detected no phytomelatonin in the C. arabica samples collected from different altitudinal locations in Rwanda following two extraction methods, even though melatonin supplements from pharmaceutical outlets manufactured in the USA (110 %), Canada (106 %), Denmark (102 %), and Belgium (2.8 %) had detectable melatonin. Rwandan C. arabica has no phytomelatonin but shows increased caffeine content with increasing locational altitude. Further studies to analyze the precursors and enzymes involved in the phytomelatonin biosynthetic pathways in plants are needed to unravel this mystery.
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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) | 0.000 | 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".