Curcumin-micellar casein multisite interactions elucidated by surface plasmon resonance

• Published in: International journal of biological macromolecules 2019-07, Vol.133, p.860-866
• Main Authors: Hudson, Eliara Acipreste, de Paula, Hauster Maximiler Campos, da Silva, Richard Marins, Pires, Ana Clarissa dos Santos, da Silva, Luis Henrique Mendes
• Format: Article
• Language: English
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2019.04.166

Determine the thermodynamic and kinetic parameters of interaction between micellar casein (MC) and curcumin (CUR) is useful for the application of MC-CUR systems in food products. We used surface plasmon resonance (SPR) and ultraviolet-visible spectrophotometry (UV–vis) to study the complex formation between MC obtained from skimmed milk and CUR, MC carrying capacity, and thermal protection for CUR at a pH of 6.6. An MC could carry about 18,000 molecules of CUR. SPR suggested an enthalpy-driven process (∆H° = −64.63 kJ∙mol−1 and T∆S° ranging from −42.45 to −44.46 kJ∙mol−1). Temperature increased reduced the rate of MC-CUR complex formation and increased its dissociation rate. The activation energy for the formation of MC-CUR activated complexes was negative for association of free MC and CUR molecules (−62.8 kJ mol−1) and positive for dissociation of the thermodynamically stable complexes (1.80 kJ mol−1). MC protected the CUR against its thermal degradation when it was subjected to different temperatures (30, 40, 50, and 60 °C for 5.5 h). This study shows the importance of characterizing MC-small molecules interactions for better application of MC as a nanocarrier. •Micellar casein (MC) of 180 nm can carry about 18,000 molecules of curcumin (CUR).•SPR measurements showed that the MC-CUR complex formation was exothermic.•Temperature increasing reduced MC-CUR association but increased its dissociation rate.•MC exhibited thermal protection for CUR.