Ultrasound-assisted formation of chitosan-glucose Maillard reaction products to fabricate nanoparticles with enhanced antioxidant activity
Supapit Viturat, Masubon Thongngam, Namfone Lumdubwong, Weibiao Zhou, Utai Klinkesorn
Abstract
The influence of ultrasonic processing parameters including reaction temperature (60, 70 and 80 °C), time (0, 15, 30, 45 and 60 min) and amplitude (70, 85 and 100%) on the formation and antioxidant activity of Maillard reaction products (MRPs) in a solution of chitosan and glucose (1.5 wt% at mass ratio of 1:1) was investigated. Selected chitosan-glucose MRPs were further studied to determine the effects of solution pH on the fabrication of antioxidative nanoparticles by ionic crosslinking with sodium tripolyphosphate. Results from FT-IR analysis, zeta-potential determination and color measurement indicated that chitosan-glucose MRPs with improved antioxidant activity were successfully produced using an ultrasound-assisted process. The highest antioxidant activity of MRPs was observed at the reaction temperature, time and amplitude of 80 °C, 60 min and 70%, respectively, with ∼ 34.5 and ∼20.2 μg Trolox mL−1 for DPPH scavenging activity and reducing power, respectively. The pH of both MRPs and tripolyphosphate solutions significantly influenced the fabrication and characteristics of the nanoparticles. Using chitosan-glucose MRPs and tripolyphosphate solution at pH 4.0 generated nanoparticles with enhanced antioxidant activity (∼1.6 and ∼ 1.2 μg Trolox mg−1 for reducing power and DPPH scavenging activity, respectively) with the highest percentage yield (∼59%), intermediate particle size (∼447 nm) and zeta-potential ∼ 19.6 mV. These results present innovative findings for the fabrication of chitosan-based nanoparticles with enhanced antioxidant activity by pre-conjugation with glucose via the Maillard reaction aided by ultrasonic processing.