Encapsulation and stabilization of lactoferrin in polyelectrolyte ternary complexes.

Area of Science:

• Food Science
• Biomaterials Science
• Protein Chemistry

Background:

• Lactoferrin (LF) is a bioactive protein with valuable properties but is prone to denaturation by heat and environmental factors.
• This instability limits its application in functional food products, necessitating improved delivery and stabilization strategies.

Purpose of the Study:

• To develop novel polyelectrolyte ternary complexes to enhance the thermal stability and retain the antibacterial activity of lactoferrin (LF).
• To investigate the structure-property relationships of these complexes, particularly focusing on multiphase coacervates.

Main Methods:

• Formulation of ternary complexes using LF, gelatin (G), and negatively charged polysaccharides (gum Arabic, soy soluble polysaccharide, high methoxyl pectin).
• Characterization of complex structures, including interpolymeric complexes and coacervates (multiphase coacervates observed).
• Assessment of thermal stability via heat treatment (90°C for 2 min, 145°C for 30 s) and evaluation of retained LF structure and antibacterial activity.

Main Results:

• Ternary complexes, especially with gum Arabic (GA), soy soluble polysaccharide (SSP), and high methoxyl pectin (HMP), significantly improved LF thermal stability.
• The GA-LF-G complex exhibited remarkable stability, retaining >90% native LF after severe heat treatment, compared to ~7% for LF control.
• LF within the ternary complexes maintained significant antibacterial activity against Gram-positive and Gram-negative bacteria post-heat treatment.

Conclusions:

• Polyelectrolyte ternary complexes effectively enhance lactoferrin's thermal stability and preserve its bioactivity, overcoming limitations in functional food applications.
• The observed multiphase coacervate structure, particularly in the GA-LF-G complex, shows potential as a versatile template for encapsulating and stabilizing other sensitive bioactives and peptides.