FT-NIR spectra collected directly from the supernatant of apple
wine samples using a MPA FT-NIR spectrometer (Bruker Optics,
Germany) in the range of 12,000 to 4000 cm1, which equipped
with an InGaAs detector and a liquid fiber optic probe with a 2 mm
path length. An air background was employed as a probe reference,
and the liquid probe directly immersed into samples for collecting
the spectra at 25 C. The spectral resolution was set at 8 cm1 with
an interval of 2 cm1 and the spectra were recorded performing 20
scans for both the reference and tested samples. The spectra were
recorded in triplicate and an average spectrum was collected to
ensure an adequate signal-to-noise ratio for the subsequent analysis.
The NIR instrument control, spectra scanning, and initial data
processing were performed by using OPUS software version 5.5