Identification of fluorescent nanoparticles from roasted sweet potato (Ipomoea batatas) during normal cooking procedures

Fluorescent nanoparticles (FNs) were identified from roasted sweet potato with a particle size of 7.0, 2.8, 2.4 nm for peel FNs, and 2.3, 1.9, 2.2 nm for pulp FNs after roasting at 250 degrees C for 20, 40, and 60 min, respectively. Blue fluorescence of FNs was observed under ultra-violet light excitation. The fluorescence intensity of the FNs increased when they were transferred from acidic to alkaline environment, and the FNs showed good photo-stability. The fluorescence of peel and pulp FNs was quenched 42.65% and 35.59%, respectively, in vitro digestion. The FNs could be absorbed by the digestive tracts of mice and enter liver, heart, kidney, brain, lung and testis. A distinct interaction between FNs and dopamine was confirmed in weakly alkaline aqueous solution. This work provided useful information in understanding the property of FNs generated in plant-based food of roasted sweet potato during normal cooking.