Microstructure of canola protein-guar gum gels: A bench note

Author(s): Florence O.Uruakpa

Plant proteins contribute to structure of food products via the formation of three-dimensional matrix which can entrap water and other food components. Establishing the structural factors responsible for gelation of canola protein isolate (CPI) in food systems will enhance the understanding of texture development in foods containing plant protein ingredients. Microstructural assessment was performed using scanning electron microscope. The influence of pH (6, 10) and 0.15Mdithiothreitol on themolecular forces responsible for structural alignment of CPI-guar gum gels was examined. CPI-guar gum gels prepared at optimum gelling condition (20 % w/v CPI, 1.5% w/v guar gum, 0.05 M NaCl, pH 10) had strong beaded strands. Evidence from gel micrographs showed improved network structure when CPI and guar gumare mixed (due to protein-protein and protein-polysaccharide interactions) and of complete breakdown of CPI-guar gum network structure (seen as excessive disrupted gel microstructure) in mixed gels containing dithiothreitol. Canola protein-guar gum microstructure may provide insight on the mechanisms and basis of texture formation in mixed foods containing proteins. These findings would allow newer protein sources such as canola protein to compete effectively with other predominant plant proteins such as soy proteins.

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