Purification and characterisation of a glutamic acid-containing peptide with calcium-binding capacity from whey protein hydrolysate

作     者：Huang, Shun-Li Zhao, Li-Na Cai, Xixi Wang, Shao-Yun Huang, Yi-Fan Hong, Jing Rao, Ping-Fan 

作者机构：Fuzhou Univ Coll Biosci & Biotechnol Fuzhou 350002 Peoples R China Fujian Agr & Forestry Univ Coll Food Sci Fuzhou 350002 Peoples R China 

出 版 物：《JOURNAL OF DAIRY RESEARCH》 (J. Diary Res.)

年 卷 期：2015年第82卷第1期

页      面：29-35页

核心收录：

学科分类：0832[工学-食品科学与工程（可授工学、农学学位）] 0905[农学-畜牧学] 08[工学] 

基　　金：National Marine Public Welfare Projects Natural Science Foundation of China [31471623, 31201287] Fujian Natural Science Foundation, China [2013J01132] Fujian Provincial Key Laboratory of Photocatalysis-State Key Laboratory Breeding Base, China 

主　　题：Whey protein hydrolysis calcium-binding peptide separation 

摘      要：The bioavailability of dietary ionised calcium is affected by intestinal basic environment. Calcium-binding peptides can form complexes with calcium to improve its absorption and bioavailability. The aim of this study was focused on isolation and characterisation of a calcium-binding peptide from whey protein hydrolysates. Whey protein was hydrolysed using Flavourzyme and Protamex with substrate to enzyme ratio of 25 : 1 (w/w) at 49 degrees C for 7 h. The calcium-binding peptide was isolated by DEAE anion-exchange chromatography, Sephadex G-25 gel filtration and reversed phase high-performance liquid chromatography (RP-HPLC). A purified peptide of molecular mass 204 Da with strong calcium binding ability was identified on chromatography/electrospray ionisation (LC/ESI) tandem mass spectrum to be Glu-Gly (EG) after analysis and alignment in database. The calcium binding capacity of EG reached 67.81 mu g/mg, and the amount increased by 95% compared with whey protein hydrolysate complex. The UV and infrared spectrometer analysis demonstrated that the principal sites of calcium-binding corresponded to the carboxyl groups and carbonyl groups of glutamic acid. In addition, the amino group and peptide amino are also the related groups in the interaction between EG and calcium ion. Meanwhile, the sequestered calcium percentage experiment has proved that EG-Ca is significantly more stable than CaCl2 in human gastrointestinal tract in vitro. The findings suggest that the purified dipeptide has the potential to be used as ion-binding ingredient in dietary supplements.