In the last years, there has been a growing movement in consumer demand for products derived from plant proteins to replace those based on animal proteins due to factors such as changes in dietary habits, restrictive eating for health reasons and environmental sustainability. Despite increasing global interest, there are still many challenges to be overcome, so that these replacements do not cause nutritional and technical-functional damage. In this sense, it is important to know the performance and specific interactions of plant proteins in various fields where animal proteins are already successfully operating. Peanuts are considered one of the main sources of vegetable proteins in the world because of their high nutritional value, low cost, and ready availability. Arachin and conarachin are the main protein constituents of peanuts. In this sense, the aim of this study was to evaluate the thermodynamics and kinetics of arachin-Congo red (ARA-CR) and conarachin-Congo red (CON-CR) interactions by surface plasmon resonance at different temperatures and ionic strengths. 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)[ARA-CR]〗^0 ) from 3.52 to 2.44 × 103 M-1 and K_(b〖(25°C)[CON-CR]〗^0 ) from 15.1 to 12.5 × 103 M-1). The shielding of the electrical double layer favored ARA-CR hydrophilic interactions (〖∆H〗_(〖[ARA-CR]〗^0)^0 = -30.60 to -42.98 kJ mol-1). On the other hand, hydrophobic interactions came to dominate during the formation of 〖[CON-CR]〗^0 (〖∆H〗_(〖[CON-CR]〗^0)^0 = -11.21 to 28.34 kJ mol-1 and 〖T∆S〗_(25°C〖[CON-CR]〗^0)^0 = 12.64 to 51.73 kJ mol-1). The data presented here improve our understanding of plant-based protein nanocarriers of small bioactive molecules.