Novel method for the identification of the variety of grape using their capability to form gold nanoparticles

Abstract

Gold nanoparticles (AuNPs) have been obtained using musts (freshly prepared grape juices where solid peels and seeds have been removed) as the reducing and capping agent. Transmission Electron Microscope images show that the formed AuNPs are spherical and their size increases with the amount of must used. The size of the AuNPs increases with the Total Polyphenol Index (TPI) of the variety of grape. The kinetics of the reaction monitored using UV-Vis shows that the reaction rates are related to the chemical composition of the musts and specifically to the phenols that can act as reducing and capping agents during the synthesis process. Since the particular composition of each must produces AuNPs of different sizes and at different rates, color changes can be used to discriminate the variety of grape. This new technology can be used to avoid fraud.