Abstract
Accelerated storage tests of whey protein concentrate were carried out to characterize changes of the proteins that may affect its nutritional quality or functional properites. After 42 days at 37°C and 75% relative humidity, pH 4.6 soluble protein decreased only slightly (14% loss), and there were no significant changes of sulfhydryl or disulfide content, Hydroxymethylfurfural increased dramatically (17 to 192μmoles/100g whey protein concentrate). “Free” lactose, and total, dinitrobenzenesulfonate-available and pepsin-pancreatin-digestible lysine contents also decreased (17, 34, 57, and 72% losses). Samples were darker after storage. Diffuse reflectance spectra showed increased absorbance at 420 as well as at 280nm. Gel filtration high performance liquid chromatography indicated formation of high molecular weight (> 200,000) aggregates that could be detected at 225 and 420nm in the absence or presence of mercaptoethanol. Polyacrylamide gel electrophoresis also suggested formation of large aggregates unable to penetrate the gel. Protein-carbohydrate products were suggested in a negatively charged fraction with high electrophoretic mobility, which was stained with the glycoprotein stain, periodic acid fuchsin sulfite.
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.
