Abstract:To explore the feasibility of using tea polysaccharides as the template for the preparation of selenium nanoparticles (SeNPs), Yunnan large-leaf green tea, black tea, and Pu’er tea, Fuding Dabai white tea, Yinghong 9 yellow tea, and Lingtou Dancong oolong tea were used as the raw materials. Crude polysaccharides were extracted from these varieties of tea through water extraction and alcohol precipitation, and their yields and contents of carbohydrates and proteins were compared. Subsequently, SeNPs were prepared by using the crude tea polysaccharides as templates. The average hydrodynamic radius, total light intensity, Zeta potential and polydispersity index of SeNPs were analyzed by dynamic light scattering and laser Doppler velocimetry. The particle size, morphology and the distribution of SeNPs were characterized by transmission electron microscopy and scanning electron microscopy. Finally, the selenium concentration of the tea polysaccharide-SeNP complexes with the highest stability was determined by inductively coupled plasma mass spectrometry, and the binding of SeNPs to the templet was characterized by Fourier transform infrared spectroscopy. The results showed the crude polysaccharides from different varieties of tea trees and tea leaves all exhibited a stabilizing effect on SeNPs, and the polysaccharides from Pu'er tea exerted the strongest effect (with the smallest SeNP diameter (75 nm), highest electrostatic stability (zeta potential: -53 mV), and the most concentrated distribution (polydispersity Index: 0.11)). The Pu’er tea polysaccharides might bind to SeNPs mainly via noncovalent interaction through the -OH, -NH2 and -C=O groups.
