[关键词]
[摘要]
为探究以茶多糖为模板制备纳米硒的可行性,以云南大叶种绿茶、红茶、普洱茶和福鼎大白白茶、英红九号黄茶、岭头单丛乌龙茶为原料,采用水提醇沉法提取茶叶粗多糖,比较其得率和多糖、蛋白质组成,并以各茶类粗多糖为模板制备纳米硒,采用动态光散射和激光多普勒测速技术分析其平均水合直径、总光强、Zeta电位和多分散系数,采用透射电子显微镜和扫描电子显微镜表征其颗粒大小、形貌和分布特性,并对稳定性最佳的茶多糖-纳米硒,采用电感耦合等离子体质谱检测其硒浓度,采用傅里叶变换红外光谱分析其与模板的结合。结果表明,不同品种茶树、茶类的粗多糖均有稳定纳米硒的作用,但以普洱茶粗多糖作用最强,所构建的纳米硒直径最小(75 nm)、静电稳定性最高(Zeta电位-53 mV)、分布最集中(多分散系数0.11),主要通过-OH、-NH2、-C=O等基团以非共价键与纳米硒结合。
[Key word]
[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.
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[基金项目]
现代农业产业技术体系建设专项资金(CARS-19);广东省自然科学基金项目(2018A030313917);广东省普通高校青年创新人才项目(2017KQNCX019)