title: Protein denaturation of whey protein isolates (WPIs) induced by high intensity ultrasound during heat gelation.
abstract: In this study, the impact of high intensity ultrasound (HIU) on proteins in whey protein isolates was examined. Effects on thermal behavior, secondary structure and nature of intra- and intermolecular bonds during heat-induced gelling were investigated. Ultrasonication (24 kHz, 300 W/cm(2), 2078 J/mL) significantly reduced denaturation enthalpies, whereas no change in secondary structure was detected by circular dichroism. The thiol-blocking agent N-ethylmaleimide was applied in order to inhibit formation of disulfide bonds during gel formation. Results showed that increased contents of α-lactalbumin (α-La) were associated with increased sensitivity to ultrasonication. The α-La:β-lactoglobulin (β-Lg) ratio greatly affected the nature of the interactions formed during gelation, where higher amounts of α-La lead to a gel more dependent on disulfide bonds. These results contribute to clarifying the mechanisms mediating the effects of HIU on whey proteins on the molecular level, thus moving further toward implementing HIU in the processing chain in the food industry.
authors: Department of Food Science, Aarhus University, P.O. Box 50, 8830 Tjele, Denmark.
authors: Rikke P
authors: RP
authors: Frydenberg
authors: Department of Food Science, Aarhus University, P.O. Box 50, 8830 Tjele, Denmark.
authors: Marianne
authors: M
authors: Hammershøj
authors: Arla Strategic Innovation Centre, Arla Foods, 8200 Brabrand, Denmark.
authors: Ulf
authors: U
authors: Andersen
authors: Arla Food Ingredients, Soenderupvej 26, 6929 Videbaek, Denmark.
authors: Marie T
authors: MT
authors: Greve
authors: Department of Food Science, Aarhus University, P.O. Box 50, 8830 Tjele, Denmark. Electronic address: lars.wiking@food.au.dk.
authors: Lars
authors: L
authors: Wiking
mesh_terms: D002942:Circular Dichroism; D005782:Gels; D006358:Hot Temperature; D011489:Protein Denaturation; D014465:Ultrasonics; D000067816:Whey Proteins / Q000737:chemistry*
chemical_list: D005782:Gels; D000067816:Whey Proteins
keywords: Circular dichroism; Denaturation; Differential scanning calorimetry; Dynamic rheology; High intensity ultrasound; Protein structure; Whey protein isolates