Immobilization of selected enriched polyphenol oxidases and their biocatalysis in organic solvent media
Bibliographic record
Abstract
Polyphenol oxidase (PPO) enzymatic extracts were recovered from apple fruit and potato tubers and enriched by an acetone precipitation. The enriched PPO extracts were immobilized by adsorption onto a wide range of inorganic supports, including chitin, alumina oxide, glass beads, Celite, Dowex and Silica gel using selected media, including water, sodium phosphate buffer and a ternary micellar system. The highest immobilization efficiencies and specific activities were obtained when the PPO extracts were suspended in sodium phosphate buffer and adsorbed onto alumina oxide. Biocatalysis of the free and immobilized PPO extracts was investigated in selected organic solvent media, including hexane, heptane, toluene and dichloromethane, using chlorogenic acid, catechin, and the endogenous phenolic compounds from apple fruit and potato tubers as substrate models. In the organic solvent media, the free PPO extracts from apple and potato demonstrated optimal enzymatic activities at 28°C and between 25 to 35°C, respectively, whereas the immobilized extracts both showed optimal enzymatic activities at 30°C. The free and immobilized extracts from apple and potato also showed similar pH values for optimal enzymatic activity in the range of 6.0 to 6.5. The immobilized apple and potato PPO extracts demonstrated a 1.5 to 1.8 and 2.1 to 3.2-fold increases in PPO activity, respectively, compared to those observed with their free counterparts, and the lowest Km values were obtained with chlorogenic acid followed by catechin and the endogenous phenolic compounds. The immobilized and free PPOs from apple and potato also showed higher Vmax values in the hexane medium followed the heptane, toluene and dichloromethane media. The end products of PPO biocatalysis were purified by size-exclusion chromatography and detected at 280 nm for the residual catechin and endogenous phenolic compounds, and at 320 nm for the PPO-catalyzed end products. Spectroscopic scanning
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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 | 0.000 | 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) | 0.003 | 0.001 |
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".