Competitive Binding of Gingerol Homologs to Fish Myofibrillar Protein Reduces the Retention of Aldehydic Off-Odor Compounds

Persistent aldehydic off-notes in fish products are influenced not only by lipid oxidation but also by protein-associated retention of odor-active aldehydes. A remaining question is how gingerol side-chain length and aldehyde structure jointly alter this apparent retention. Mackerel myofibrillar protein (MP) was therefore combined with (E)-2-decenal (T2D), (E,E)-2,4-decadienal (DDE), or trans-4,5-epoxy-(E)-2-decenal (E2D), with or without 6-, 8-, or 10-gingerol. Headspace solid-phase microextraction–gas chromatography–mass spectrometry, interaction disruptors, spectroscopy, molecular docking, and 100 ns molecular dynamics simulations were integrated. All three gingerols decreased the apparent aldehyde-binding ratio of MP. At 125 µmol/g protein, 10-gingerol reduced T2D, DDE, and E2D binding from approximately 81%, 72%, and 85% to 68%, 65%, and 68%, respectively. Spectroscopic responses were consistent with changes in the optical and conformational environment; fluorescence was interpreted as apparent quenching without numerical inner-filter correction, and CD band changes provided evidence of a treatment-related conformational response without assigning exact secondary-structure fractions. Docking ranked 8-gingerol most favorably, whereas the selected binary MYH7-10-gingerol trajectory showed greater pocket residence and a more favorable MM/GBSA estimate than the corresponding MYH7-DDE trajectory. The combined evidence supports a three-layer working model involving matrix partitioning, protein-level site accessibility, and pocket-level competition. These findings provide a mechanistic basis for sensory validation rather than direct proof of deodorization.