Functional properties of locust bean gum and lambda-carrageenan mixtures in dairy creams

Some physico-chemical and rheological properties of dairy creams, commercial and formulated with different quantities of LBG and/or λ-carrageenan, were analyzed in order to study the functional properties of the additive mixtures in these systems. For the formulation of creams, a central composed factorial design (with 5 levels) was used, adding LBG and/or λ-carrageenan in the range 0 to 0.1% of each one of them, being 0.17% the maximum amount of both hydrocollaids.;Whipping properties at 8°C were evaluated from overrun (volume increase of the sample) and whipping time. Rheological properties of the whipped and unwhipped samples were examined with a rheometer. The gap between the plate-plate geometry used (75 mm diameters) was set at 1 mm. All the tests were carried out at 5°C. In the rheological studies of the unwhipped creams shear stress shear rate curves were obtained and fitted to different models (Herschel-Bulkley and Cross).;For rheological characterization of the whipped samples Creep Compliance and Dynamic tests were carried out in samples immediately after whipping, after 24h in refrigeration (5°C) and after freezing (24h and 1 month at −18°C). Parallely, the stiffness of all whipped samples was determined in an extrusion test. Refrigerated and frozen samples were a also characterized in their serum leakage during storage.;The whipping time of creams was affected by the interaction between the polymers, showing the maximum values for the highest concentrations of λ-carrageenan and low concentrations of LBG. The air incorporation capacity of creams decreases when the λ-carrageenan concentration. The refrigerated and frozen storage supposes a small decrease of the overrun depending on the gum mixture. A greater stability of creams was observed when the amount of the additives was greater than 0.085%, as reflected by the maximum force evaluated from extrusion test. Differences in the rheological parameters and in the stability of samples during refrigeration and freezing were observed in function of the gum mixture composition. Freezing represents a collapse of the foam structure, but the results suggest an interaction between the polymers that favors the stability of the whipped creams storage in a limited range of concentrations.