Interfacing β-casein - Phenolic compound interactions via molecular dynamics simulations with diffusion kinetics in...

Area of Science:

• Food Science and Technology
• Biophysics
• Nutraceutical Chemistry

Background:

• Understanding diffusion kinetics is crucial for bioactive compound delivery in food and nutraceutical systems.
• Protein-bioactive interactions can influence the release and bioavailability of functional ingredients.

Purpose of the Study:

• To investigate the impact of protein-bioactive interactions on the diffusion kinetics of phenolic compounds.
• To quantify the effect of bovine β-casein on the diffusion rates of ferulic acid and epicatechin.

Main Methods:

• Examined diffusion kinetics of ferulic acid and epicatechin in the presence and absence of bovine β-casein.
• Employed pulling simulations and umbrella sampling to determine binding energies between protein and phenolic compounds.
• Calculated diffusion coefficients to assess the impact of interactions.

Main Results:

• Protein presence decreased the diffusion rate of ferulic acid from 2.76 × 10^-11 to 8.51 × 10^-12 m²/s.
• Protein presence decreased the diffusion rate of epicatechin from 1.33 × 10^-11 to 1.00 × 10^-12 m²/s.
• Binding energies were determined as -4.6 kcal/mol (protein-ferulic acid) and -6.7 kcal/mol (protein-epicatechin), correlating with diffusion rate changes.

Conclusions:

• Protein-bioactive interactions significantly impede the diffusion of phenolic compounds in food matrices.
• The strength of interaction, quantified by binding energy, governs the reduction in diffusion rate.
• Bioactive dissociation from the matrix may be the rate-limiting step for diffusion in low-solid systems, highlighting the utility of simulation methods.