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Impact of redox agents on the physico-chemistry of wheat gluten proteins during hydrothermal treatment

Author:
Lagrain, B., Brijs, K., Delcour, J.A.
Source:
Journal of cereal science 2006 v.44 no.1 pp. 49-53
ISSN:
0733-5210
Subject:
wheat gluten, suspensions, water, hot water treatment, oxidants, potassium bromate, dithiothreitol, viscosity, gliadin, glutenins, crosslinking, extraction, detergents, sodium dodecyl sulfate
Abstract:
The impact of the oxidants potassium bromate and potassium iodate and the reducing agent dithiothreitol (DTT) on the rheological behaviour of 20% (w/v) gluten-in-water suspensions during thermal treatment was monitored with the rapid visco analyser (RVA). The suspensions were subjected to a linear temperature increase from 40 to 95 °C in 14 min, a holding step of 40 min at 95 °C, a cooling step (7 min) with a linear temperature decrease to 50 °C, and a final holding step at 50 °C (13 min). Potassium iodate (1.18 and 1.77 μmol/g protein) and potassium bromate (1.52 and 15.2 μmol/g protein) decreased RVA viscosities in the holding step and increased sodium dodecyl sulphate (SDS) protein extractabilities suggesting a greater heat resistance and decreased gliadin-glutenin cross-linking. In contrast, in the presence of DTT (1.65 and 3.30 μmol/g protein) RVA viscosity increased at lower temperatures and lowered SDS extractabilities. It is postulated that low concentrations of reducing agent facilitate gliadin-glutenin cross-linking during heating while oxidants hinder gluten polymerization due to decreased levels of free sulphydryl groups and less flexibility of the glutenin chains.
Agid:
688686