Znse 45 hatr horizontal attenuated total reflectance crystal

FTIR spectral data were collected using a ZnSe 45° HATR (Horizontal Attenuated Total Reflectance) crystal (PIKE Technologies, Madison, Wisconsin, United States), and a FTIR-6200 JASCO spectrometer (Jasco Corp., Tokyo, Japan). The crystal used has a refractive index of 2.4 and a depth of penetration of 2.0 μm at 1000 cm⁻¹. Spectra were collected over the wavenumber range of 4000 to 400 cm⁻¹ using the Spectra Manager™ Code of Federal Regulations (CFR) software version 2 (Jasco Corp.), by accumulating 100 scans with a resolution of 4 cm⁻¹ and a total integration time of 2 min.
A small portion from each meat sample was transferred to the crystal plate, covered with a small piece of aluminum foil, and then pressed to ensure the best possible contact with the crystal. Prior to the measurements of the samples, reference spectra were acquired using the cleaned blank (no added sample) crystal. After each measurement, the crystal’s surface was cleaned, first with detergent and distilled water and then with analytical grade acetone, and dried using lint-free tissue. As previously practiced [15 (link)], the FTIR spectra that were ultimately used in further analyses were in the approximate wavenumber range of 1800 to 900 cm⁻¹.

The FTIR spectral data were collected using a ZnSe 45° HATR (Horizontal Attenuated Total Reflectance) crystal (PIKE Technologies, Madison, Wisconsin, USA), and an FTIR-6200 JASCO spectrometer (Jasco Corp., Tokyo, Japan). The spectra acquisition process consists of cutting a small portion from each sample and placed to the crystal plate, covered with a small piece of aluminum foil. The specific crystal works at a refractive index of 2.4 and a depth of penetration of 2.0 μm @ 1,000 cm⁻¹. Then the acquired spectra were processed and collected by the Spectra Manager™ Code of Federal Regulations (CFR) software version 2 (Jasco Corp.). The corresponding wavenumber range is 4,000–400 cm⁻¹, while 100 scans with a resolution of 4 cm-1 and a total integration time of 2 min were accumulated. The FTIR spectra that were used in further analyses were in the approximate wavenumber range of 2,700–1,000 cm⁻¹, i.e. 1,700 wavelengths (sample features), resulted by removing the water peak starting at ~ 2,700 cm⁻¹ and ignoring the range [400–1,000 cm⁻¹] as it mainly represents noise.