Revealing Covariance Structures in Fourier Transform Infrared and Raman Microspectroscopy Spectra: A Study on Pork Muscle Fiber Tissue Subjected to Different Processing Parameters

Abstract

The aim of this study was to investigate the correlation patterns between Fourier transform infrared (FT-IR) and Raman microspectroscopic data obtained from pork muscle tissue, which helped to improve the interpretation and band assignment of the observed spectral features. The pork muscle tissue was subjected to different processing factors, including aging, salting, and heat treatment, in order to induce the necessary degree of variation of the spectra. For comparing the information gained from the two spectroscopic techniques with respect to the experimental design, multiblock principal component analysis (MPCA) was utilized for data analysis. The results showed that both FT-IR and Raman spectra were mostly affected by heat treatment, followed by the variation in salt content. Furthermore, it could be observed that IR amide I, II, and III band components appear to be effected to a different degree by brine-salting and heating. FT-IR bands assigned to specific protein secondary structures could be related to different Raman C-C stretching bands. The Raman C-C skeletal stretching bands at 1,031, 1,061, and 1,081 cm(-1) are related to the IR bands indicative of aggregated beta-structures, while the Raman bands at 901 cm(-1) and 934 cm(-1) showed a strong correlation with IR bands assigned to a alpha-helical structures. At the same time, the IR band at 1,610 cm(-1), which formerly was assigned to tyrosine in spectra originating from pork muscle, did not show a correlation to the strong tyrosine doublet at 827 and 852 cm(-1) found in Raman spectra, leading to the conclusion that the IR band at 1,610 cm(-1) found in pork muscle tissue is not originating from tyrosine.

Raman and FTIR microscopic imaging of colon tissue: a comparative study

“…The combined application of Raman and FTIR imaging was used to compare, to complement and to confirm the findings. A number of interesting chemometric approaches such as the multiblock principal component analysis [24] could be employed in the future for a combined analysis after image fusion. Advantages of FTIR imaging were shorter acquisition times and higher spectral quality.…”

The Development of Infrared Microspectroscopy (IMS) and Its Applications in Agricultural and Aquatic Products

“…IMS could make further research on meat during various processing methods, such as the changes in secondary structures of proteins, water distribution, and myofibrillar tissue (50)(51)(52)(53)(54).…”

“…They also found the relationship between changes of protein secondary structure, water proton T 2 relaxation time, and cooking loss (60). Downloaded by [Stony Brook University] at 23:03 01 November 2014 FTIR and Raman spectroscopy provide complementary information on biomolecules, and in 2007 the combination of these two methods was used to study pork muscle tissue, intending to provide a more accurate interpretation and band assignment of the observed spectral features (53). The data obtained were analyzed by multiblock PCA.…”

“…The IR band at 1610 cm −1 was formally assigned to tyrosine in spectra of pork muscle, but in this research, it didn't show any correlation to the strong tyrosine doublet at 827 and 852 cm −1 in the Raman spectra. So, Bocker et al (53) concluded that the IR band at 1610 cm −1 of pork muscle tissue was not originating from tyrosine.…”

Metallomics, elementomics, and analytical techniques

“…The combining application of both FTIRM and Raman microspectroscopy can provide valuable information about the biochemical composition since FTIR spectra are due to polar functional groups while the bands in Raman spectra are due to nonpolar functional groups, which has been used in bone [143], pork muscle [144], bacterial strains [145], and human tissues [146].…”