Determination of anthocyanin and moisture content of purple sweet potatoes during drying process by their optical properties in the 400–1050 nm range

•Absorption (μa) and scattering (μs')properties of PSP under drying were determined.•The μa and μs' of PSPs correlated with their moisture and anthocyanin content.•The μs' increased with increasing drying time, different from the behaviors of μa.•Prediction models of anthocyanin/moisture in PSPs were developed using μa and μs'.