Application of Congo red dye as a molecular probe to investigate the kinetics and thermodynamics of the formation processes of arachin and conarachin nanocomplexes. (1st August 2022)

• Record Type: Journal Article
• Authors: Rezende, Jaqueline de Paula; De Paula, Hauster Maximiler Campos; Freitas, Talma Duarte; Coelho, Yara Luiza; Da Silva, Luis Henrique Mendes; Pires, Ana Clarissa dos Santos
• Is Part Of: Food chemistry. Volume 384(2022)
• Publication Date: 2022-08-01
• Subjects: Plant-based protein -- Nanocarriers -- Transition complex -- Surface plasmon resonance -- Hydrophobic/hydrophilic balance; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2022.132485
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: Peanut proteins (ARA or CON) interact with Congo red (CR) to form stable complexes. CON has a higher binding affinity toward CR than does ARA. Hydrophilic interactions were the main driving forces for [ A R A - C R ] 0 formation process. The formation of [ C O N - C R ] 0 was enthalpically and entropically driven. Transition complexes had a more structured conformation than their stable form. Abstract: The thermodynamics and kinetics of arachin-Congo red ( ARA - C R ) and conarachin-Congo red ( CON - C R ) interactions were studied using surface plasmon resonance. KCl led to a reduction of up to 55% in the values of the associated kinetic constants, but it had less influence on the dissociation rates (less than 12%). The change in ionic strength had little effect on the thermodynamic stability of the complexes, but it did reduce their affinities ( K b ( 25 ° C ) [ A R A - C R ] 0 from 3.52 to 2.44 × 10 3 M −1 and K b ( 25 ° C ) [ C O N - C R ] 0 from 15.1 to 12.5 × 10 3 M −1 ). The shielding of the electrical double layer favored ARA - C R hydrophilic interactions ( Δ H [ A R A - C R ] 0 0 decreased from −30.60 to −42.98 kJ mol −1 ). On the other hand, hydrophobic interactions came to dominate during the formation of [ C O N - C R ] 0 ( Δ H [ C O N - C R ] 0 0 increased from −11.21 to 28.34 kJ mol −1 and T Δ S 25 ° C [ C O N - C R ] 0 0 increased from 12.64 to 51.73 kJ.mol −1 ). The data presented here improve our understanding of plant-based protein nanocarriers of small bioactive molecules.