Article

Light-Scattering Study of the Structure of Aggregates and Gels Formed by Heat-Denatured Whey Protein Isolate and β-Lactoglobulin at Neutral pH

Université du Maine, Le Mans, Pays de la Loire, France
Journal of Agricultural and Food Chemistry (Impact Factor: 3.11). 04/2007; 55(8):3104-11. DOI: 10.1021/jf063029g
Source: PubMed

ABSTRACT The structure of aggregates and gels formed by heat-denatured whey protein isolate (WPI) has been studied at pH 7 and different ionic strengths using light scattering and turbidimetry. The results were compared with those obtained for pure beta-lactoglobulin (beta-Lg). WPI aggregates were found to have the same self-similar structure as pure beta-Lg aggregates. WPI formed gels above a critical concentration that varied from close to 100 g/L in the absence of added salt to about 10 g/L at 0.2 M NaCl. At low ionic strength (<0.05 M NaCl) homogeneous transparent gels were formed, while at higher ionic strength the gels became turbid but had the same self-similar structure as reported earlier for pure beta-Lg. The length scale characterizing the heterogeneity of the gels increased exponentially with increasing NaCl concentration for both WPI and pure beta-Lg, but the increase was steeper for the former.

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