Protein structural changes and characteristic intermediate accumulations in dried abalone driven by the Maillard...

The role of the Maillard reaction in shaping dried abalone quality during drying was investigated. During the drying process, a progressive increase in browning intensity and in the color parameters ΔE and BI was observed in abalone muscle. SDS-PAGE analysis revealed aggregation of proteins such as myosin heavy chain, while PAS staining confirmed the formation of glycoprotein polymers. CD spectroscopy analysis indicated that the reaction led to a reduction in α-helix content from 29.89% to 6.52%, alongside increases in β-sheet and random coil contents to 48.52% and 28.48%, respectively, accompanied by a marked decrease in intrinsic fluorescence intensity. Dynamic substrate analysis showed significant reductions in glucose and key amino acids, including Glu, Lys, and Phe, facilitating the generation and accumulation of 18 Amadori and Heyns compounds. Seven compounds of Fru-Tyr, Fru-Phe, Glu-Met, Fru-pGlu, Fru-Lys, Glu-Gln, and Fru-Val, were identified as characteristic biomarkers of dried abalone through principal component analysis. A predictive model based on near-infrared spectroscopy and partial least squares regression achieved high predictive accuracy for these seven markers, with determination coefficients exceeding 0.90 and root mean square errors of prediction below 0.20. These findings demonstrate that the Maillard reaction induces protein glycation in abalone muscle, accompanied by the accumulation of Amadori/Heyns compounds, providing a theoretical basis for quality precise control in dried abalone processing.