Summary Protein isolates of Lupinus albus were obtained from full fat and defatted lupin flour using isoelectric precipitation or dialysis. Calorimetric tests demonstrated that the main protein fractions of the isolates denature well below 100 °C. Mechanical spectra of isolate dispersions obtained at 80 °C indicated the formation of a ‘pseudogel’ whose cohesion increased during cooling to 10 °C. Subsequent heating to 90 °C encouraged extensive formation of disulphide bonds as it produced gels that were insoluble in sodium dodecyl sulphate and urea solutions. Dialysis produced isolates of lower gelling concentrations, which also formed networks of a stronger relative elastic character. The presence of NaCl at concentrations up to 0.5 m had a reinforcing effect on networks. Protein over‐aggregation caused the opposite effect at higher salt levels. Finally, a comparison with results in the literature on soybean protein gelation suggested similar denaturation temperatures and a common pattern of structure formation for the two legume proteins.
Low‐fat, low‐cholesterol materials were extracted from spray‐dried egg yolk using as solvents petroleum ether, petroleum ether/ethanol, ethanol/water, and supercritical CO2. The four extracts and their source (spray‐dried yolk) were incorporated into traditional recipes for oil in water salad dressings. The linear viscoelasticity of these systems was characterised by dynamic oscillation and creep/relaxation curves on a stress‐controlled Carri‐Med rheometer. The high protein content of the extracts generates stronger and more elastic structures than those of commercial salad dressings but they are comparable to the viscoelastic properties of commercial mayonnaises which contain high cholesterol egg yolk. Measurements of the size of oil droplets over a period of eleven days demonstrate that these emulsions maintain acceptable consistency. The methodology adopted and the conclusions derived might assist in the purposeful formulation of low‐cholesterol salad dressings.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.