The Role of Iron and the Factors Affecting Off-Color Development of Polyphenols
Bibliographic record
Abstract
Iron deficiency affects over two billion people worldwide (Lotfi, M.; Venkatesh Mannar, M. G.; Merx, R. J.; Naber-van den Heuvel, P. Micronutrient Fortification of Foods: Current Practices, Research,and Opportunities; Micronutrient Initiative: Ottawa, Ontario, Canada, 1996). However, fortifying foods with highly bioavailable iron is technically challenging because of off-color and off-flavor development, catalytic degradation of vitamins, and oxidation of lipids. The role of highly bioavailable iron in the off-color development of foods and beverages is not well-understood. The goal of this research was to examine the interaction of iron with simple phenolics and polyphenols. Factors that may affect off-color development, such as pH, oxygen, temperature, and reducing and chelating agents, were evaluated as a model for food products. Our results demonstrated that the iron that reacts with the simple phenolic, catechol, to develop off-color must be in the oxidized state, and the iron is reduced in the presence of catechol. Because this is an oxidation/reduction reaction, the redox potential of all of the components is critical to the color development. Ferrous iron sources with low redox potentials and ferric iron sources with high redox potentials caused off-color development with catechol. Only polyphenols that contain ortho-hydroxyl groups cause off-color development with iron. All of the factors tested affect off-color development and redox potential of the system. Low pH, low oxygen, high temperature, and the presence of reducing and chelating agents inhibited off-color development. To confirm the model, foods that contained these polyphenols were evaluated for off-color development when iron was added. The foods tested reacted similarly to the models of polyphenols with iron. Off-color development was caused by oxidation-reduction interactions between ferric iron and polyphenols that contained ortho-dihydroxyl groups. Ferrous iron needed to be oxidized to participate in off-color development. In addition, methods identified in the models to prevent off-color development were effective in most of the food products examined. Using the ferrous form of iron and maintaining it in its reduced form by lowering pH, removing oxygen, and including reducing agents, it was possible to fortify foods with highly bioavailable iron.
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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 | 0.001 |
| 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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".