Title
Determination of heat-set gelation capacity of a quinoa protein isolate (Chenopodium quinoa) by dynamic oscillatory rheological analysis
Author
Elaine Kaspchak, Marco Aurelio Schüler de Oliveira, Fernanda Fogagnoli Simas, Célia Regina Cavicchiolo Franco, Joana Léa Meira Silveira, Marcos Rogério Mafra, Luciana Igarashi-Mafra
Year
2017
Journal
Food Chemistry
Abstract
This work aimed to study the influence of pH (3.5 and 7.0) and CaCl2 and MgCl2 addition on heat-set gelation of a quinoa protein isolate at 10% and 15% (w/w). The protein isolate obtained was composed mainly of 11S globulin as was observed by electrophoresis and mass spectrometry analysis. Heat-set gelation occurred at both pH values studied. Nevertheless, the gels formed at pH 3.5 were more viscoelastic and denser than those formed at pH 7.0, that was coarser and presented syneresis. The CaCl2 and MgCl2addition increased the gel strength during rheological analysis at pH 3.5, possibly due to the formation of fiber-like connections in the gel network. At pH 7.0, the divalent salts resulted in weaker gels formed by agglomerates, suggesting a neutralization of the protein surface charges. The differences in quinoa protein gelation were attributed to solubility, and the flexibility of proteins secondary structure at the pH studied.
Instrument
J-815
Keywords
Circular dichroism, Secondary structure, Chemical stability, Biochemistry