
How does Pectin function as a protein stabilizer in acidified dairy and plant-based milk drinks?
High Methoxyl (HM) Pectin acts as a steric stabilizer by wrapping around milk proteins (like casein) to prevent aggregation and serum separation in low pH environments (pH 3.8 - 4.2).
At neutral pH, milk proteins are negatively charged and repel each other. When the pH drops toward their isoelectric point (~pH 4.6), they lose their charge and clump together, causing curdling. HM Pectin carries a negative charge in this range; its backbone adsorbs onto the positively charged regions of the casein micelles, creating a protective layer. The hydrophilic hairy regions of the pectin expand into the continuous phase, providing steric hindrance that keeps the protein particles suspended even after heat treatment (UHT/HTST).
