# Structural changes and exposed amino acids of ethanol-modified whey proteins isolates promote its antioxidant potential.
> エタノール処理によるホエイタンパク質単離物の構造変化とアミノ酸露出が抗酸化能に与える影響


## Abstract

Whey protein isolates (WPI) were subjected to ethanol concentrations ranging from 20% to 80% (v/v) to examine structural unfolding and aggregation behavior. Turbidity increased and solubility declined in a concentration-dependent fashion, with circular dichroism spectroscopy and total sulfhydryl measurements confirming that aggregate formation proceeded primarily through disulfide bonds and intramolecular hydrogen bonding. Ethanol-modified WPI (E-WPI) demonstrated markedly greater antioxidant activity than native WPI across multiple assays. The enhancement was attributed to increased surface exposure of hydrophobic, aromatic, and sulfur-containing amino acid residues following molecular unfolding. Among all conditions tested, 40% ethanol yielded the highest antioxidant performance, suggesting an optimal balance between unfolding and excessive aggregation. These findings indicate that controlled ethanol modification is an effective strategy for improving the antioxidant potential of WPI.

### Mechanism

Ethanol-driven unfolding of WPI exposes hydrophobic, aromatic, and sulfur-containing amino acids at the protein surface; subsequent aggregation via disulfide bonds and intramolecular hydrogen bonds collectively elevates antioxidant activity.

## Bibliographic

- **Authors**: Feng YQ, Yuan DW, Kong B, Sun F, Wang M, Wang H, et al.
- **Journal**: Curr Res Food Sci
- **Year**: 2022
- **PMID**: [36110385](https://pubmed.ncbi.nlm.nih.gov/36110385/)
- **DOI**: [10.1016/j.crfs.2022.08.012](https://doi.org/10.1016/j.crfs.2022.08.012)
- **PMC**: [PMC9468495](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9468495/)
- **Study type**: in vitro study
- **Delivery route**: in vitro
- **Effect reported**: positive

## Delivery context

This is basic research at the cellular or molecular level. For human application, inhalation is the most promising delivery route, but inhalation carries explosion risk and concentration matters (empirical LFL of 10%; high-concentration devices are not recommended).

## Safety notes

This is basic research at the cellular or molecular level. For human application, inhalation is the most promising delivery route, but inhalation carries explosion risk and concentration matters (empirical LFL of 10%; high-concentration devices are not recommended).

See also:
- [Inhalation concentration and LFL / UFL](https://h2-papers.org/en/safety-notes/inhalation-concentration)
- [Consumer Affairs Agency accident cases](https://h2-papers.org/en/safety-notes/accident-cases)
- [Inhalation safety threshold lineage](https://h2-papers.org/en/safety-notes/lineage)

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> **Cite as**: H2 Papers — PMID 36110385. https://h2-papers.org/en/papers/36110385
> **Source**: PubMed PMID [36110385](https://pubmed.ncbi.nlm.nih.gov/36110385/)