The effects of pH and NaCl concentration on the structure of β-casein from buffalo milk.

In the present study, we aimed to investigate the effects of pH and sodium chloride (NaCl) concentration on the structure of β-casein (β-CN) purified from buffalo milk using circular dichroism (CD), intrinsic tryptophan, and anilino-8-naphthalene sulfonate (ANS) fluorescence spectroscopy. We found that NaCl concentration played a critical role in the stability of the secondary structure of β-CN. The CD negative peak had a redshift as the NaCl concentration was increased and accompanied by a decrease of β-sheet content and an increase of α-helix content. ANS fluorescence spectroscopy also indicated that higher NaCl concentration and lower pH significantly affected the tertiary structure of β-CN. Dynamic light scattering (DLS) results showed that the particle size of buffalo β-CN had a blueshift, and then a redshift within the pH range of 5.0-7.5, and it showed a redshift when the NaCl concentration was increased. © 2021 The Authors. Food Science & Nutrition published by Wiley Periodicals LLC.

Citation

Kong Yang Wu, Tong Xiang Yang, Quan Yang Li. The effects of pH and NaCl concentration on the structure of β-casein from buffalo milk. Food science & nutrition. 2021 May;9(5):2436-2445

PMID: 34026061

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