The effects of pH, temperature, and buffer concentration on the self-assembling behavior, secondary structure, and surface hydrophobicity of donkey and bovine β-casein
Jingjing Zhang, Silvia Vincenzetti, Paolo Polidori, Valeria Polzonetti, Alessandro Di Michele, Diego Romano Perinelli +3 more
Food Chemistry
Abstract
The self-assembling behavior, secondary structure, and surface hydrophobicity of purified donkey β-casein in terms of pH, temperature, and buffer concentration were investigated in comparison with commercial bovine β-casein. Critical micelle concentration of both β-caseins decreased with the lowering of pH (pH 8.0-6.0) and the increasing temperatures (25-50 °C). Critical micelle temperature of both β-caseins increased moving from pH 6.0 to 8.0 and aggregates larger than micelles formed at pH 6.0 that is close to their isoelectric point. Fluorescence spectroscopy analysis demonstrated that the maximum surface hydrophobicity was achieved at pH 6.0. The secondary structure was examined using circular dichroism spectroscopy, highlighting an increase of α-helix content and a decrease of unordered structures with the decrease of pH and increase of temperature. This work provides insights on parameters promoting molecular interactions involved in donkey β-CN self-association, useful to develop nanocarriers for encapsulating bioactive compounds in pharmaceutical and nutraceutical applications.
Extracted Claims
5 claims extracted from this paper into the knowledge graph
pH and temperature affect critical micelle concentration of β-caseins
“Critical micelle concentration of both β-caseins decreased with the lowering of pH (pH 8.0-6.0) and the increasing temperatures (25-50 °C)”
pH affect critical micelle temperature of β-caseins
“Critical micelle temperature of both β-caseins increased moving from pH 6.0 to 8.0”
pH and temperature affect secondary structure
“an increase of α-helix content and a decrease of unordered structures with the decrease of pH and increase of temperature”