Redox State Detection of Fruits and Vegetables by a Simple Surface-Enhanced Raman Scattering Method

In order to detect the redox states of fruits and vegetables simply, a SERS (surface-enhanced Raman scattering) method was developed based on a redox-sensitive probe and a pH-sensitive probe. The two probes were dropped onto the flesh of the fresh incision of fruits and vegetables, respectively. The SERS spectra of redox-sensitive probes were used to indicate their redox states, and the SERS spectra of pH-sensitive probes were used to indicate their pH values to discount the influence of pH on the redox states. The order of redox states (redox potential) of the detected fruits and vegetables is as follows: carrot < Green delicious apple < Xinjiang kuerle fragrant pear < Chinese royal pear < Fuji apple < crystal pear < Golden marshall apple < potato. Compared with traditional methods based on the detection of extracts, the developed method is simple without any pretreatments and consumption of additional chemicals, which would become a popular evaluation methodology of the redox states of fruits and vegetables during their growth and storage stages.