Nanoencapsulation of anthocyanins-loaded β-lactoglobulin nanoparticles: Characterization, stability, and bioavailability in vitro

This work aims to investigate the effect of desolvation on the stability and bioavailability of nanoparticles of β-lactoglobulin (β-Lg) and anthocyanins (AC) extracted from red raspberry pomace. Interactions between the substrates were also studied using multispectral approaches. β-Lg-nanoparticles were fabricated via heat treatment at 85 °C for 30 min before initiating the desolvation method at pH 7. This method generated monodisperse particles, nano-scale size of β-Lg, and AC-β-Lg ranged from 129.13 to 351.85 nm with square morphology obtained by SEM. The AC extract was encapsulated successfully during desolvation process into β-Lg-nanoparticles with encapsulation efficiency (EE %) of ~77%. Results also showed that AC (from 1 to 13 × 10−4 M) quenched the fluorescence intensity of de-solvated β-Lg estimated to be 98%, and a binding among them occurred with a Ka-value of 7.59 × 108 M−1 at 25 °C. Addition of AC also gradually increased the antioxidant activity of β-Lg-nanoparticles with values of 82.51% at the highest AC-concentration (13 × 10−4 M) loaded on β-Lg-nanoparticles. AC-loaded β-Lg nanoparticles was more stable in mouth (pH 6.8), simulated gastric (SG, pH 2), and simulated intestinal (SI, pH 6.9) by showing high retention rate (%) than that of AC unencapsulated. Overall, de-solvated-β-Lg increased the heat-stability and bioavailability of AC, which could be further utilized in various food and pharmaceutical matrices. These findings recommend that β-Lg nanoparticles could be appropriated as delivery systems for anthocyanins.