养殖暗纹东方鲀肌肉中呈味肽的分离鉴定

Isolation and Identification of Flavor Peptides in Cultured Puffer Fish(Takifugu obscurus)

本文旨在从生鲜暗纹东方鲀肌肉中提取呈味肽从而对暗纹东方鲀肌肉中的呈味肽的结构特性进行相应研究。将生鲜养殖暗纹东方鲀肌肉水提物经Sephadex G15凝胶柱分离,得到3个多肽组分(分别为0-F1、0-F2和0-F3),感官评价结合电子舌选择出具有最强烈的鲜味和kokumi感的组分0-F1。采用反相高效液相色谱(RP-HPLC)对其进行进一步分离得到2个组分0-F1-1和0-F1-2,电子舌鉴定显示0-F1-1组分有较强的鲜味。最后利用基质辅助激光解析电离飞行时间质谱(MALDI-TOF-MS)对RP-HPLC分离得到组分0-F1-1中呈味肽氨基酸序列进行测定,鉴定得到一种新的呈味七肽结构:Pro-A-Ala-B-Met*-Cys-Arg(810.9046 Da,A和B均为氨基酸代码,Met*表示氧化型甲硫氨酸)虽然肽段中含有大量的疏水性氨基酸,但该肽不具有苦味,而且有显著的浓厚感,其中含有的Cys残基可能是其具有kokumi感的关键。

The aim of this study was to isolate and study the structural properties of flavor peptides from raw, cultured puffer fish muscle. Three fractions （0-F1, 0-F2, and 0-F3） were obtained from an aqueous extraction of cultured puffer fish （Takifugu obscurus） muscle by Sephadex G-15 gel filtration chromatography. Using sensory evaluation analysis and an electronic tongue, it was found that fraction 0-F1 could elicit umami and kokumi tastes. Further isolation of fraction 0-F1 components was performed using reverse-phase high-performance liquid chromatography （RP-HPLC） to yield two subfractions 0-Fl-1 and 0-F1-2. The electronic tongue showed that subfraction 0-FI-1 could elicit a relatively strong umami taste. The amino acid sequence of subfraction 0-F1-1 isolated by RP-HPLC was identified using matrix-assisted laser desorption-ionization time-of-flight mass spectrometry （MALDI-TOF-MS） and the structure of this new flavor peptide was Pro-A-Ala-B Met＊-Cys-Arg （810.9046 Da, where A and B are amino acid codes; Met＊ is oxidative methionine）. Although this peptide contained a large number of hydrophobic amino acids, it did not have a bitter taste, and rather a thick and strong taste. Hydrophilic amino acid residue Cys might be the key factor contributing to the kokumi taste of this peptide.