The Impact of Different Withering Process Conditions on the Bioactivity and Quality of Black Tea from Azorean Camellia sinensis
Bibliographic record
Abstract
The objective of this study was to investigate the variability of natural bioactive compounds, such as catechin, theaflavin, total phenolic content (TPC), and total flavonoid content (TFC), of Azorean black tea (Camellia sinensis L., O. Kuntze) as well as its antioxidant activities according to different withering times. The TPC, TFC, free radical scavenging activity (FRSA), ferric reducing antioxidant power (FRAP), and ferrous-ion-chelating (FIC) activities were determined by colorimetric methods, and catechin and theaflavin contents were analyzed by high-pressure liquid chromatography (HPLC). The FRSA shows similar results for the withering range of 6 to 16 h (hours). For FRAP, the best results were observed at 16 h, and for FIC, the highest value was at 20 h. The TPC and TFC showed the highest value at 9 h and the lowest at 20 h. For the total theaflavins, the highest results were obtained after 12 h of withering, and the lowest values were obtained at 16 and 20 h. According to the different withering times, the highest value of total catechin levels was at 12 h, while the lowest value was observed at 20 h. Regarding caffeine content, all samples presented similar results, with the exception of the 12 h time point. In conclusion, the best withering times were observed in the range of 9 to 16 h, showing decreased values at 20 h, with the exception of FIC.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 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".