Development of an optical sensing strategy based on gold nanoparticles formation driven by polyphenols. Application to food samples

In this work the basis for the development of two methods for evaluating the antioxidant capacity of food matrices were laid. One of the two methods involves the extraction of the phenolic fraction for the evaluation of the antioxidant capacity of polyphenols extract in aqueous solvent, while the other does not include a sample pre-treatment thus allowing an extraction free evaluation of the antioxidant capacity directly in the matrix. Both methods exploit the synthesis of gold nanoparticles (AuNPs), which present a diameter of a few tens of nm, via the reduction of chloroauric acid driven by the phenolic compounds. For the spectrophotometric reading, the absorption band of localized surface plasmon resonance (LSPR) that have produced AuNPs at 540 nm is used as analytical signal.