title: Principal component similarity analysis of Raman spectra to study the effects of pH, heating, and kappa-carrageenan on whey protein structure.
abstract: Raman spectroscopy was used to elucidate structural changes of beta-lactoglobulin (BLG), whey protein isolate (WPI), and bovine serum albumin (BSA), at 15% concentration, as a function of pH (5.0, 7.0, and 9.0), heating (80 degrees C, 30 min), and presence of 0.24% kappa-carrageenan. Three data-processing techniques were used to assist in identifying significant changes in Raman spectral data. Analysis of variance showed that of 12 characteristics examined in the Raman spectra, only a few were significantly affected by pH, heating, kappa-carrageenan, and their interactions. These included amide I (1658 cm(-1)) for WPI and BLG, alpha-helix for BLG and BSA, beta-sheet for BSA, CH stretching (2880 cm(-1)) for BLG and BSA, and CH stretching (2930 cm(-1)) for BSA. Principal component analysis reduced dimensionality of the characteristics. Heating and its interaction with kappa-carrageenan were identified as the most influential in overall structure of the whey proteins, using principal component similarity analysis.
mesh_terms: D002351:Carrageenan / Q000494:pharmacology*; D004220:Disulfides / Q000737:chemistry; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D011489:Protein Denaturation; D017433:Protein Structure, Secondary; D012710:Serum Albumin, Bovine / Q000737:chemistry; D013059:Spectrum Analysis, Raman; D014364:Tryptophan / Q000737:chemistry; D014443:Tyrosine / Q000737:chemistry
chemical_list: D004220:Disulfides; D012710:Serum Albumin, Bovine; D014443:Tyrosine; D014364:Tryptophan; D002351:Carrageenan