Revealing the mechanism underlying the effects of γ-aminobutyric acid-dioscorin interactions on dioscorin structure and emulsifying properties by molecular dynamic simulations

• Published in: Food research international 2023-09, Vol.171, p.112982-112982, Article 112982
• Main Authors: Chen, Yun-long, Nie, Hao-nan, Dong, Hui, Gao, Qi, Peng, Xue, Wang, Ning, Chen, Xueling, Liu, Qing-zheng, Li, Jiang-kuo, Xu, Xiang-bin, Xue, You-lin
• Format: Article
• Language: English
• Subjects: Dioscorin; Emulsifying properties; Freeze-drying; gamma-Aminobutyric Acid; Hydrophobic and Hydrophilic Interactions; Molecular Dynamics Simulation; Plant Proteins - chemistry; Solubility; Spray-drying; γ-Aminobutyric acid
• ISSN: 0963-9969; 1873-7145
• DOI: 10.1016/j.foodres.2023.112982

[Display omitted] •FD dioscorin had a higher ESI and SD dioscorin had a higher EAI.•GABA induced the exposure of the hydrophobic groups of dioscorin.•GABA changed the conformation of dioscorin by increasing β-sheet and coil contents.•GABA promoted more adsorption of dioscorin to the O/W interface.•MD simulation showed GABA interacts with dioscorin mainly through Coulomb interactions. Many studies have shown that γ-aminobutyric acid (GABA) exhibits various beneficial biological activities, including gut-modulating, neuro-stimulating, and cardio-protecting activities. Naturally, GABA exists in small amounts in yam, which is primarily synthesized by the decarboxylation of L-glutamic acid in the presence of glutamate decarboxylase. Dioscorin, the major tuber storage protein of yam, has been shown to have good solubility and emulsifying activity. However, how GABA interacts with dioscorin and affects their properties has yet to be clarified. In this research, the physicochemical and emulsifying properties of GABA-fortified dioscorin, which was dried by spray drying and freeze drying, were studied. As results, the freeze-dried (FD) dioscorin produced more stable emulsions, while the spray-dried (SD) dioscorin adsorbed more rapidly to oil/water (O/W) interface. The fluorescence spectroscopy, ultraviolet spectroscopy and circular dichroism spectroscopy showed that GABA changed the structure of dioscorin, by exposing its hydrophobic groups. The addition of GABA significantly promoted the adsorption of dioscorin to the O/W interface and prevented droplets coalescence. The results of molecular dynamics simulation (MD) showed that GABA destroyed the H-bond network between dioscorin and water, increased surface hydrophobicity and finally improved the emulsifying properties of dioscorin.