Photon emission properties of roasted soybean as related to reactive oxygen scavenging activities

Photon emission, from water extract of roasted soybean (RE) in the presence of hydrogen peroxide, was investigated. The photon intensity of RE was proportional to browning (observed at 420 nm) and fluorescence (Ex. 370 and Em. 440 nm) as a function of roasting time. This photon intensity could be improved by the several conditions, such as roasting time, alkalinity, and the combination of metallo compound. The maximum wavelengths of emission spectra of RE were around 560 nm under various conditions. RE also had reactive oxygen scavenging activities in proportion to the photon intensity. Our work suggests that the photon intensity of RE is closely related to the reactive oxygen-scavenging properties. This fact may be utilized to estimate the function and quality of food, especially roasted food.