Contributions of molecular size, charge distribution, and specific amino acids to the iron-binding capacity of sea cucumber (Stichopus japonicus) ovum hydrolysates

卷:230

Sun, Na ; Cui, Pengbo ; Jin, Ziqi ; Wu, Haitao ; Wang, Yixing ; Lin, Songyi

Dalian Polytech Univ

关键词: Sea cucumber ovum;    Iron binding;    Molecular size;    Amino acids;    Characterization;   

DOI  :  10.1016/j.foodchem.2017.03.077

学科分类：食品科学和技术

【 摘 要 】

This study investigated the contributions of molecular size, charge distribution and specific amino acids to the iron-binding capacity of sea cucumber (Stichopus japonicas) ovum hydrolysates (SCOHs), and further explored their iron-binding sites. It was demonstrated that enzyme type and degree of hydrolysis (DH) significantly influenced the iron-binding capacity of the SCOHs. The SCOHs produced by alcalase at a DH of 25.9% possessed the highest iron-binding capacity at 92.1%. As the hydrolysis time increased, the molecular size of the SCOHs decreased, the negative charges increased, and the hydrophilic amino acids were exposed to the surface, facilitating iron binding. Furthermore, the Fourier transform infrared spectra, combined with amino acid composition analysis, revealed that iron bound to the SCOHs primarily through interactions with carboxyl oxygen of Asp, guanidine nitrogen of Arg or nitrogen atoms in imidazole group of His. The formed SCOHs-iron complexes exhibited a fold and crystal structure with spherical particles. (C) 2017 Elsevier Ltd. All rights reserved.