3.1. Investigation of the instrument setup for optimal
spectral acquisition
Due to each mangosteen sample having different internal
factors such as translucent flesh, hardening pericarp and
seeds, the dynamic ranges of the SW-NIR intensity spectra
were very different, especially, between translucent flesh and
hardening pericarp. The hardening pericarp, which is usually
produced after a physical shock during harvesting and
transporting, caused low signal-to-noise ratio spectra because
its tissue has low light-penetration. Therefore, preliminary
tests were conducted to determine the optimum conditions for
measuring all mangosteens. About 1000 mangosteens were
thus used for the investigation of the measurement conditions
using the basic procedure described above.