Food Chemistry

Isoelectric point pI

The pH at which a protein carries no net electrical charge, so electrostatic repulsion between molecules is minimal.

Real-life application

Why paneer and cheese are made by adjusting milk's acidity — the proteins clump together and separate from the whey at this exact pH.

Related terms

Loss of a protein's secondary, tertiary and quaternary structure without breaking peptide bonds, caused by heat, pH change, salts, solvents or shear.

The main phosphoprotein of milk, about 80% of milk protein, existing as micelles stabilised by κ-casein. Precipitates at pH 4.6 or on rennet action.

Practise the subject behind the definition.