Academic article

Salt-induced changes in pork myofibrillar tissue investigated by FT-IR microspectroscopy and light microscopy

Böcker, Ulrike; Ofstad, Ragni; Bertram, Hanne; Egelandsdal, Bjørg; Kohler, Achim

Publication details

Journal: Journal of Agricultural and Food Chemistry, vol. 54, p. 6733–6740–8, 2006

Publisher: American Chemical Society (ACS)

Issue: 18

International Standard Numbers:
Printed: 0021-8561
Electronic: 1520-5118

Open Access: none


FT-IR microspectroscopy and light microscopy were used to investigate pork muscle musculus semitendinosus samples, taken from three animals, that were subjected to brine salting at different concentrations (0.9, 3, 6, and 9% NaCl). Differences in spectral characteristics and in microstructure were observed in meat from animals differing in initial pH and varying salt concentrations. The FT-IR data displayed changes in the amide I region from 1700 to 1600 cm(-1). This spectral range was analyzed by principal component analysis (PCA) and partial least-squares regression (PLSR). These methods revealed correlations between the spectral data and the different animals, salt content, moisture content, pH value, and myofiber diameter. A shrinking share of R-helical components was related to an increase in salt concentration in the muscle. At the same time, a greater share in nonhydrogenated C=O groups (1668 cm(-1)) was related to an increase in salt concentration in the meat. The share of aggregated,beta-strands differed with respect to the different animals but was not influenced by salt concentration. The meat at higher pHs (> 6) had less aggregated,beta-strands than that at lower pHs (5.6-5.7). It could be demonstrated that simultaneous with changes in microstructure, pH value, salt, and moisture content were alterations in the protein amide I region as measured by FT-IR microspectroscopy, revealing a relationship between these biophysical and chemical parameters and secondary protein structure attributes.