Internal Quality Assessment of Mandarin Fruit by vis/NIR Spectroscopy

Different measurement modes (reflectance, interactance and transmission) and spectral windows (500–1100 nm) were compared for their ability to predict non-destructively the harvest soluble solids content (SSC) and titratable acidity (TA) of Satsuma Mandarin ( Citrus reticulata cv. “Miyagawa”). A direct transmission measurement mode (source and sensor opposite sides of fruit) coupled with a single spectral window from 700 to 930 nm delivered the most accurate SSC predictions ( R 2 = 0.93, RMSEP = 0.32%). Accurate TA prediction was not possible with any measurement mode and the predictive ability that was achieved (best results: R 2 ∼ 0.65, RMSEP ∼ 0.15%) was only afforded indirectly through a correlation with the skin chlorophyll changes that occur as the fruit mature.