Rejane de Castro Santana

High- and Low-Energy Emulsifications for Food Applications: A Focus on Process Parameters

High-energy emulsification is traditionally used to produce food-grade emulsions. However, energy input, design of the device and the type of surfactant should be carefully evaluated to achieve the desired emulsion properties. The low-energy processes, as spontaneous emulsification and phase inversion temperature, are alternative methods for producing systems with high stability and smaller particle sizes. Nevertheless, the surfactants and cosurfactants frequently used to produce emulsions from the low-energy process are not food grade or require a higher concentration than is allowed in food products. In this review, the characteristics of emulsions produced from low- and high-energy emulsifications, the mechanisms of droplet formation and their stability are reviewed with a particular focus on recent studies addressing the effects of process parameters on the properties of food emulsions. Knowing the principles and limitations of high- and low-energy processes, adequate process conditions and future trends are suggested depending on the system composition and the desired properties of the final product.

Rheological and structural evaluations of commercial italian salad dressings

The emulsion stability, composition, structure and rheology of four different commercial italian salad dressings manufactured with traditional and light formulations were evaluated. According to the results, the fat content ranged from 8% (w/w) (light) to 34% (w/w) (traditional), the carbohydrate concentration varied between 3.8% (w/w) (traditional) and 14.4% (w/w) (light) and the pH was between 3.6-3.9 for all samples. The microscopic and stability analyses showed that the only stable salad dressing was a light sample, which had the smallest droplet size when compared with the other samples. With respect to the rheological behaviour, all the salad dressings were characterized as thixotropic and shear thinning fluids. However, the stable dressing showed an overshoot at relatively low shear rates. This distinct rheological behavior being explained by the differences in its composition, particularly the presence of a maltodextrin network.