2.7 Micro-structural properties of Acha flour and
cookies
2.7.1 Fourier transmission-infrared (FTIR) spectroscopy
Fourier transmission-infrared spectroscopy analysis was carried out
using the method of Adebiyi et al. (2016); Animashaun and
Sobowale (2024). An FTIR spectrophotometer (Thermo Scientific Smart iTR,
(Attenuated Total Reflectance), Thermo Scientific Inc., USA) was used to
determine the samples’ FTIR spectra. Before sample (0.5 g of achaflour and cookies) were mounted on the instrument, the background
spectra of the instrument were collected and at 16 runs per scan, the
records of the spectra were taken with characteristics peaks in wave
numbers ranging from 400 to 4000 cm-1 at.
2.7.2 X-ray diffraction (XRD)
The Adebiyi et al. (2016) method was used to conduct the X-ray
diffraction analysis. 5 g of samples were put into the XRD sample holder
and compressed with a stainless steel weight. The crystalline property
and X-ray diffraction of the samples were examined using an X-ray
diffractometer (Rigaku-ultima IV, Japan) fitted with a divergence slit.
The diffractometer was operated at 40 kV 40 mA with a scan speed of 1
0/min. The X-ray diffractogram’s areas for the crystalline and amorphous
regions were used to calculate the relative crystallinity (RC).
2.7.3 Scanning electron microscopy (SEM)
The Adebiyi et al. (2016) method was used to analyze the scanning
electron microscopy. The acha flour and cookies were placed on
aluminum stubs and sprayed with a carbon thin film using a carbon coated
Quorum Q150TE, Quorum Technologies, UK, to avoid the charge effect.
After coating, the samples were transported to an electron beam specimen
chamber in a scanning electron microscope (Vega 3 XMU, TESCAN Czech
Republic) and exposed to an electron beam while under vacuum.