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.