Heat-induced whey protein isolate fibrils: Conversion, hydrolysis, and disulphide bond formation
2006; Elsevier BV; Volume: 17; Issue: 7 Linguagem: Inglês
10.1016/j.idairyj.2006.10.002
ISSN1879-0143
AutoresSuzanne G. Bolder, Astrid J Vasbinder, Leonard M.C. Sagis, Erik van der Linden,
Tópico(s)Muscle metabolism and nutrition
ResumoFibril formation of individual pure whey proteins and whey protein isolate (WPI) was studied. The heat-induced conversion of WPI monomers into fibrils at pH 2 and low ionic strength increased with heating time and protein concentration. Previous studies, using a precipitation method, size-exclusion method, or proton NMR spectroscopy, reported a wide range of values for the conversion. An alternative method was developed, namely centrifugal filtration, giving a consistent picture of the conversion. The present results help to explain the disparities reported in literature. No fibrils formed upon heating pure α-lactalbumin or pure BSA at pH 2, whereas fibrils formed in pure β-lactoglobulin (β-lg) and WPI solutions. Experiments indicate that β-lg was the only whey protein involved in fibril formation. In all whey protein samples, hydrolysis occurred during heating at pH 2, as determined by HPLC and SDS-PAGE. When WPI fibrils formed at pH 2 were stored at pH 7 or 10, disulphide bonds were formed in the samples.
Referência(s)