Thermal-induced alterations in complexes based on lactoferrin and low/high methoxyl pectin: Physicochemical,...

Area of Science:

• Food Science
• Biochemistry
• Materials Science

Background:

• Lactoferrin (LF) is a valuable protein with antimicrobial and nutritional properties.
• Pectin, a polysaccharide, can form complexes with proteins to modify their properties.
• Understanding LF-pectin interactions is crucial for food applications, especially under thermal stress.

Purpose of the Study:

• To investigate the interaction mechanisms between lactoferrin (LF) and low methoxyl pectin (LMP) or high methoxyl pectin (HMP).
• To analyze the effects of heat treatment on the physicochemical, structural, and functional properties of LF-pectin complexes.
• To compare the efficacy of LMP versus HMP in stabilizing LF during thermal processing.

Main Methods:

• Complex formation at pH 7 and mass ratios of 3:1 and 1:1.
• Molecular docking and Fourier transform infrared (FTIR) spectroscopy to determine binding interactions.
• Molecular dynamic simulations for conformational stability analysis.
• Heat treatment at 95°C for 10 min to assess thermal stability.
• Analysis of particle size, zeta potential, secondary and tertiary structures, emulsifying activity, foaming performance, and antibacterial activity.

Main Results:

• LF formed soluble complexes with both LMP and HMP.
• LMP interacted mainly via electrostatic and hydrogen bonds, while HMP interacted via hydrophobic forces.
• LF-HMP complexes showed greater conformational stability than LF-LMP.
• Heat treatment reduced particle size and increased zeta potential of LF and LF-pectin complexes.
• LF-HMP maintained better structural integrity and functional properties (emulsifying, foaming, antibacterial) post-heating compared to LF-LMP.
• HMP significantly enhanced LF's emulsifying activity, foam ability, and retained antibacterial efficacy against E. coli and S. aureus post-heating.

Conclusions:

• High methoxyl pectin (HMP) offers superior stabilization for lactoferrin (LF) during heat treatment compared to low methoxyl pectin (LMP).
• The interaction type (hydrophobic for HMP vs. electrostatic/hydrogen bonds for LMP) influences complex stability.
• LF-HMP complexes are promising for applications in heat-processed food products, preserving LF's functional attributes.