Determination of Antioxidant Capacity of Chinese Rice Wine and Zhuyeqing Liquor Using Nanoparticle-Based Colorimetric Methods

Abstract

In this work, three nanoparticle-based methods, namely gold nanoparticle (AuNP) method, silver nanoparticle (AgNP) method, and iron oxide nanoparticle (IONP) method, were used to measure the antioxidant capacities of Chinese rice wine (CRW) and Zhuyeqing liquor (ZYQL). The formed nanoparticles were characterized by the UV-Vis spectroscopy and transmission electron microscopy, which conformed the generation of metal nanoparticles. In addition, it was found that the colorimetric response of AuNPs, AgNPs, and IONPs was all dependent on the amount of antioxidants contained in wine samples. Furthermore, the colorimetric methods reported in this study all showed good correlations with ferric reducing antioxidant power (FRAP) (the correlation coefficients were 0.952, 0.948, and 0.969, respectively, for AuNPs, AgNPs, and IONPs). Moreover, the formation process of nanoparticles was shown by the plots of the absorbance at absorption peak as a function of the volume of wine sample, which was a sigmoidal curve, and gave two new indexes to report the antioxidant capacity of CRW and ZYQL. Compared with traditional methods, the precision of the novel method maybe slightly lower; however, it does not require the use of expensive radical compounds and organic solvents. The overall results indicated that these three nanoparticle-based methods developed can be used as alternative methods for the determination of the antioxidant capacity in CRW and ZYQL.