Improved Thermal Stability of Lactoferrin and Oxidative Stability of Iron(II) Sulfate by Co-encapsulation with Low-Methoxyl Pectin

Complex coacervates between bovine lactoferrin (LF) and low-methoxyl pectin (LMP) were prepared to encapsulate and deliver Fe(II) as an iron fortification ingredient in food, with the goal of enhancing the protein thermal stability and minimizing Fe(II) oxidation. The impact of pH and biopolymer ratio was investigated in terms of complex yield and iron encapsulation efficiency. The thermal stability of LF at 95 °C was determined by changes in turbidity, particle size, and LF retention by HPLC. The interaction between LF and LMP prevented thermal aggregation and circular dichroism analysis showed the complexation preserved the secondary structure of the protein. LF-LMP-Fe complexes contained 28-74 mg g ⁻¹ of total iron depending on the pH of formation, with <5% of the Fe released at neutral pH. The complex coacervation system shows promise as a thermally stable ingredient for iron delivery and food fortification.