Two-dimensional visible/near-infrared correlation spectroscopy study of thawing behavior of frozen chicken meats without exposure to air

The thawing behavior of frozen chicken meats without exposure to air was investigated by generalized 2D Vis/NIR correlation spectroscopy. The synchronous 2D visible correlation analysis revealed that intensities of the 435 and 555 nm bands increase, because of the relaxation of DeoxyMb and OxyMb components, whereas those of the 475 and 620 nm bands decrease as MetMb and SulfMb decompose into small molecules due to specific enzymes. The corresponding asynchronous spectra indicated that the decomposition of MetMb and SulfMb species precedes the recovery of DeoxyMb and OxyMb, and that the DeoxyMb species recovers faster than the OxyMb. Further, the asynchronous 2D NIR spectra suggested that the melting of ice crystals and the relaxation and proteolysis of proteins occurs earlier, indicating a coordination process for hydrophilic O–H and N–H groups. Moreover, strong correlation peaks correlating the bands in the visible and NIR spectral regions were observed and discussed.