Abstract
Three food protein products, soy and whey protein isolates and spray-dried egg white powder, were deamidated to various levels by 0.04 N hydrochloric acid. The extents of deamidation were determined using an ammonia electrode. Raman spectra of the modified proteins were obtained and analyzed. A new C O stretching vibration band was observed at 1780 cm −1, attributed to γ-carboxyl groups of aspartic and glutamic acids. Calibration curves were constructed by plotting the intensity ratio of the 1780 cm −1 band to the 1003 cm −1 phenylalanine stretching band (as an internal standard) against the extent of deamidation. Linear fits were obtained with high correlation coefficients r > 0.987. Effect of deamidation on the conformation of these proteins was also studied by monitoring changes in Raman spectral characteristics, including a transition from ordered to disordered structures, exposure of tryptophan residues from a buried, hydrophobic microenvironment, and probable conformational changes of the aliphatic residues.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
