Effect of Ultrasound Treatment on Physicochemical, Microstructural and Anti-Oxidative Properties of Whey Protein Concentrate Based 3,3′-Diindolylmethane Nanoparticles

Abstract

Abstract Objectives This study evaluated the impact of ultrasound duration on the encapsulation of 3,3′-diindolylmethane (DIM) using whey protein concentrate nanoparticles. Methods Whey protein concentrate-based DIM nanoparticles were prepared and treated with different ultrasound times (0 - 20 min) with 30% amplitude. Results The results showed that ultrasound treatment significantly decreased the particle size (from 265 nm to 218 nm) and PDI value (from 0.49 to 0.43); as well as zeta potential values were notably increased. The encapsulation efficiency (EE%) increased with increasing sonication time (0–20 min) from 76% to 77, 79, 81, and 88%, respectively. The ultrasound treatment had a significant effect on the apparent viscosity, and decrease in the viscosity as a function of shear rate was observed with increasing sonication time. The transmission electronic microscopy (TEM) micrographs demonstrated that all the formulations treated with different sonication times had a smooth and uniform spherical shape and ultrasound treatment led to the reduction of particle size, especially for 20 min of ultrasound. The thermal stability of the WPC–DIM nanoparticles were enhanced with increasing sonication time by increasing peak denaturation temperature and enthalpy. The Fourier transform infrared spectroscopy (FT-IR) spectra analysis revealed that ultrasound treatment had a remarkable effect on the secondary structure of WPC–DIM nanoparticles, and electrostatic interactions and hydrogen bonds between DIM and whey protein were strengthened. Moreover, the length of ultrasound treatment exhibited a significant effect on the DPPH (2,2-diphenyl-2-picrylhydrazyl) scavenging activity (from 56% to 62%) and ABTS(2,2′-azinobis(2 ethylbenzothiazoline-6-sulfonate) scavenging activity (from 47% to 68%). Conclusions In conclusion, the ultrasound treatment successfully improved the physicochemical, microstructural, and anti-oxidative properties of WPC–DIM nanoparticles, therefore it is considered an efficient method for the development of whey protein concentrate-based DIM nanoparticles to be used for medical and nutritional applications. Funding Sources Northeast Agricultural University.