Non-covalent interaction of sacha inchi protein and quercetin: Mechanism and physicochemical property

Interactions between proteins and polyphenols are essential for the functional properties of foods. This study explores the non-covalent interactions between Sacha Inchi protein (SIP) and quercetin (Que) and examines the physicochemical characteristics of their complex. Fourier transform infrared spectroscopy and Circular dichroism indicated that Que could interact with SIP and change the secondary structure of SIP. The mechanism of Que binding significantly and quenching SIP fluorescence were revealed by fluorescence spectroscopy. The primary forces driving this interaction are hydrogen bonds and van der Waals forces. Additionally, binding with quercetin led to a marked increase in the β-sheet content of SIP and a decrease in random coil structures. With increasing Que levels, its loaded amount rose, although the encapsulation efficiency decreased. SIP-Que complexes displayed larger particle sizes and enhanced antioxidant properties than SIP alone, with antioxidant activity increasing with higher Que concentrations. Furthermore, the bioaccessibility of Que improved upon binding with SIP. This research contributes to the modification of SIP protein and its potential applications in the food industry.