Obtention, interaction, and characterization of the soy protein isolate-glycyrrhizin nanocomplex for encapsulating naringenin

Naringenin (NAR) has several potential benefits as a bioactive nutrient, but its low water solubility and poor bioavailability have limited its application. Here, a soy protein isolate-naringenin complex (NAR@SPI) was prepared for NAR delivery. Furthermore, to improve the encapsulation capacity of SPI for hydrophobic bioactive nutrients and their complex physiochemical properties, dipotassium glycyrrhizinate (DG) was used to modify SPI with a simple stirring process to obtain the SPI-DG complex, and then this complex was used to load the NAR. The final obtained nanocomplex was named NAR@SPI-DG. This novel NAR@SPI-DG has shown higher encapsulation efficiency (93.20 ± 0.27% versus 62.09 ± 3.20%) and loading capacity (8.53 ± 0.02% versus 5.89 ± 0.30%) for NAR as compared to the NAR@SPI. Spectral evaluations and molecular simulations revealed that the SPI's and DG's interaction in SPI-DG involved the combination of a spontaneous exothermic reaction, and the mechanisms of interaction were dominated by a hydrogen bond and van der Waals forces. NAR@SPI-DG has demonstrated significant improvements in solubility, in vitro antioxidant activity, in vitro anti-diabetes activity, and in vitro bioaccessibility as compared with bare NAR and NAR@SPI. Consequently, the use of DG is promising in the modification of SPI protein to construct a nano-delivery system for hydrophobic bioactive nutrients, such as NAR, in functional foods.