Effects of processing conditions on structural and functional parameters of whipped dairy emulsions containing various fatty acid compositions

Effect of Using Different Kinds and Ratios of Vegetable Oils on Ice Cream Quality Characteristics

The aim of this study was to develop ice cream products using different types of oils, a sensory ballot to focus on the textural attributes of new ice cream products, evaluate physicochemical properties of these products and physical measurements. Milkfat, hazelnut oil and olive oil were mixed at different concentrations for a total of 12% fat. Control sample contains 12% milk fat while the other formulations contain different proportion of milk fat, hazelnut oil and olive oil as the fat content. The combination of the different proportion of milk fat, hazelnut oil and olive oil are given as % milk fat, % hazelnut oil and % olive oil respectively; 12:0:0, 0:12:0, 0:0:12, 6:6:0, 6:0:6, 0:6:6, 4:4:4. The pH, free acidity, total solid ingredient, b* value and volume increase rate were statistically significant (p < 0.05). Sensory analysis results showed that: samples were 50% hazelnut oil-50% olive oil had the highest color and appearance scores. On the other hand, the highest score in body and texture scores were belongs to the sample of used 50% milk fat-50% hazelnut oil and 50% milk fat-50% olive oil, 50% milk fat-50% olive oil the most preferred ones in total quality criterions.

Effect of Shear History on Rheology of Time-Dependent Colloidal Silica Gels

This paper presents a rheological study describing the effects of shear on the flow curves of colloidal gels prepared with different concentrations of fumed silica (4%, 5%, 6%, and 7%) and a hydrophobic solvent (Hydrocarbon fuel, JP-8). Viscosity measurements as a function of time were carried out at different shear rates (10, 50, 100, 500, and 1000 s⁻¹), and based on this data, a new structural kinetics model was used to describe the system. Previous work has based the analysis of time dependent fluids on the viscosity of the intact material, i.e., before it is sheared, which is a condition very difficult to achieve when weak gels are tested. The simple action of loading the gel in the rheometer affects its structure and rheology, and the reproducibility of the measurements is thus seriously compromised. Changes in viscosity and viscoelastic properties of the sheared material are indicative of microstructural changes in the gel that need to be accounted for. Therefore, a more realistic method is presented in this work. In addition, microscopical images (Cryo-SEM) were obtained to show how the structure of the gel is affected upon application of shear.