Physicochemical properties of native and extruded maize flours in the presence of animal proteins

Abstract

Interest for protein-enriched starchy products has increased, as protein intake moderately higher than current recommendations may provide health benefits for ageing populations. Influence of the substitution of native or extruded flours by 25% or 50% of proteins (collagen, milk, whey or egg white proteins) was studied. Collagen was the only protein that increased water binding capacity (p<0.05) up to 233,72% for mixtures with native and up to 40.85% for mixtures with extruded flours. Regarding gelling properties, regardless used flour, mixtures with 50% of collagen increased water absorption index and swelling power (p<0.05) by ⁓100%, while mixtures with 50% of egg white protein decreased water absorption index by ⁓40% (p<0.05). Pasting viscosity decreased in flour-protein mixtures, except the ones with egg white protein, that increased. Endotherm peaks shifted to higher temperatures when proteins were present. Regarding viscoelastic behaviour, when using native flour and higher protein content, gels presented stronger gel behaviour.