Doucet Dany, Otter Don E, Gauthier Sylvie F, Foegeding E Allen
Department of Food Science, North Carolina State University, Raleigh, North Carolina 27695-7624, USA.
J Agric Food Chem. 2003 Oct 8;51(21):6300-8. doi: 10.1021/jf026242v.
Extensive hydrolysis of whey protein isolate by Alcalase was shown to induce gelation mainly via hydrophobic interactions. The aim of this work was to characterize the peptides released in order to better understand this phenomenon. The apparent molecular mass distribution indicated that aggregates were formed by small molecular mass peptides (<2000 Da). One hundred and thirty peptides with various lengths were identified by reversed-phase high-performance liquid chromatography coupled with electrospray ionization mass spectrometry. Alcalase was observed to have a high specificity for aromatic (Phe, Trp, and Tyr), acidic (Glu), sulfur-containing (Met), aliphatic (Leu and Ala), hydroxyl (Ser), and basic (Lys) residues. Most peptides had an average hydrophobicity of 1-1.5 kcal/residue and a net charge of 0 at the pH at which gelation occurred (6.0). Therefore, an intermolecular attractive force such as hydrophobic interaction suggests the formation of aggregates that further leads to the formation of a gel.
研究表明，碱性蛋白酶对乳清分离蛋白的广泛水解主要通过疏水相互作用诱导凝胶化。这项工作的目的是对释放的肽进行表征，以便更好地理解这一现象。表观分子量分布表明，聚集体由小分子质量肽（<2000 Da）形成。通过反相高效液相色谱与电喷雾电离质谱联用鉴定了130种不同长度的肽。观察到碱性蛋白酶对芳香族（苯丙氨酸、色氨酸和酪氨酸）、酸性（谷氨酸）、含硫（甲硫氨酸）、脂肪族（亮氨酸和丙氨酸）、羟基（丝氨酸）和碱性（赖氨酸）残基具有高特异性。大多数肽在发生凝胶化的pH值（6.0）下平均疏水性为1-1.5千卡/残基，净电荷为0。因此，诸如疏水相互作用之类的分子间吸引力表明聚集体的形成，进而导致凝胶的形成。
