Interaction between caffeic acid/caffeic acid phenethyl ester and micellar casein

Area of Science:

• Food Science
• Biochemistry
• Materials Science

Background:

• Caffeic acid (CA) and caffeic acid phenethyl ester (CAPE) are bioactive compounds with limited solubility.
• Micellar casein (MC) is a protein complex found in milk with potential for encapsulating hydrophobic molecules.

Purpose of the Study:

• To investigate the interaction between CA/CAPE and MC.
• To characterize the physico-chemical and antioxidant properties of the resulting complexes.

Main Methods:

• Fluorescence spectroscopy to analyze binding interactions.
• Fourier-transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) for complex confirmation.
• Assessment of physical properties (density, morphology) and antioxidant capacity (DPPH assay).

Main Results:

• CA and CAPE formed complexes with MC through hydrophobic interactions, with CAPE showing a higher binding constant.
• Complex formation did not alter MC's secondary structure but affected its morphology and density.
• The CA/CAPE-MC complexes exhibited enhanced thermal stability and DPPH radical scavenging capacity compared to free components.

Conclusions:

• Micellar casein effectively complexes with CA and CAPE, improving their properties.
• These findings suggest MC as a promising carrier for enhancing the stability and bioavailability of CA and CAPE.
• The study highlights the potential of casein-based systems for delivering bioactive compounds in food and pharmaceutical applications.