Fourier Transform Raman Spectroscopy Study of Heat-Induced Gelation of Plasma Proteins as Influenced by pH

• Published in: Journal of agricultural and food chemistry Vol. 54; no. 20; pp. 7890 - 7897
• Main Authors: Dàvila, Eduard, Parés, Dolors, Howell, Nazlin K
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 04.10.2006
• Subjects: acidity; albumins; alkalinity; Biological and medical sciences; blood proteins; Blood Proteins - chemistry; Disulfides - chemistry; fibrinogen; food chemistry; Food industries; food processing; Fourier Analysis; Fourier transform Raman spectroscopy; Fundamental and applied biological sciences. Psychology; gelation; gels; Gels - chemistry; globulins; heat treatment; Hot Temperature; Hydrogen-Ion Concentration; principal component analysis; protein structure; Protein Structure, Secondary; Raman spectroscopy; Spectrum Analysis, Raman; Temperature; Fourier transformation; plasma proteins; Gelation; globulins; Albumin; Environmental factor; FT-Raman spectroscopy; heat-induced gelation; Globulin; Protein; Heat; Fibrinogen; pH; Serum; Raman spectrometry; Principal component analysis
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf061512l

Fourier transform (FT) Raman spectroscopy was used to elucidate heat-induced structural changes of albumin, globulins, serum, and plasma protein solutions (15% w/w) as affected by pH (4.5, 6.0, and 7.5). Reduction of α-helix and formation of β-sheet, disulfide bond reactions, and exposure and buriedness of hydrophobic groups and amino acid residues were observed. All of these features contributed to the formation of strong, irreversible heat-induced gels. The application of a dimensionality reducing technique such as principal component analysis proved to be useful to determine the most influential qualities of protein samples, as well as the pH-dependent behavior of some of the attributes of both unheated and heated solutions. Analysis of Raman spectra in terms of differences demonstrated the interactions of albumin and globulins in co-occurrence and the significant role of fibrinogen on the gel's attributes. Keywords: FT-Raman spectroscopy; heat-induced gelation; albumin; globulins; fibrinogen; serum; plasma proteins; principal component analysis