Study on the Interaction Mechanism Between Linoleic Acid, Myristic Acid and Rice Protein by Spectroscopy

Myristic acid (MA) and linoleic acid (LA) have been widely utilized as food additives in the food industry, and have also demonstrated notable pharmacological activities. However, the molecular mechanisms underlying their interactions with rice protein (RP) remain poorly understood and warrant further systematic investigation. A comprehensive characterization of the molecular interactions between myristic acid, linoleic acid, and rice protein was conducted through UV absorption, fluorescence emission, and molecular docking analyses, enabling the determination of fluorescence quenching pathways, binding affinities, and the predominant forces responsible for complex formation. The results indicate that both myristic acid and linoleic acid induce the static quenching of rice protein fluorescence. The interaction between these fatty acids and rice protein is primarily governed by electrostatic forces. Synchronous fluorescence spectroscopy reveals that the addition of myristic acid causes negligible alterations in tyrosine fluorescence intensity, while significantly reducing tryptophan fluorescence. In contrast, linoleic acid leads to a marked decrease in fluorescence intensities of both tyrosine and tryptophan residues in rice protein. Three-dimensional fluorescence spectroscopy revealed a consistent decrease in the fluorescence intensity of rice protein upon the addition of both myristic acid and linoleic acid. Molecular docking simulations further indicated that linoleic acid exhibits a higher binding affinity toward rice protein, as reflected by its more favorable binding energy. This study elucidates the interaction mechanisms between rice protein and myristic acid or linoleic acid, providing a theoretical foundation for the practical development of rice protein-based products.