October 27/Tunis, Tunisia/Journal of Technology & Science -- "Flow properties of three industrial formulas of ice cream compound coatings were studied in the steady state regime with the coaxial geometry. Flow curves showed shear-thinning thixotropic behavior," scientists in Tunis, Tunisia, report.
"As for molten chocolate, the Casson-Steiner equation was used to fit the compound coating rheograms in the shear rate range 380-1,000 s-1. The effects of agitation rate and time applied during coating preparation were studied. A new formula of coating was realized using a mixture design and, as dependent variables, the apparent viscosities at different shear rates. the flow properties of molten compound coatings could be reproduced by this statistical method, but subsequent research on the influence of fat content and nature, and on the rheological parameters controlling the solidification of coatings, should be carried out to improve their formulation. Formulation of food materials using the scientific (and not the traditional) method is essential in predicting the quality of the final product and reducing the period and cost of developing. This method is based on the use of statistical experimental design and needs the understanding of the techno-functional properties of the food materials (such as physicochemical properties and rheological behavior). The aim of this research was to use this scientific method in developing a new coating formula. This work illustrates the importance of the mixture design and the rheological properties of molten compound coatings in their formulation. In practice, we showed that the dependent variables used in the mixture design would be chosen with great attention, with respect to the fat contained in coatings," wrote D. Ghorbel and colleagues.
The researchers concluded, "The fat nature and content has a great influence on the functional properties of the coatings used in ice cream manufacture, which is the subject of a forthcoming paper."
Ghorbel and colleagues published their study in the Journal of Food Process Engineering ("Use Of Mixture Design and Flow Characteristics to Formulate Ice Cream Compound Coatings." Journal of Food Process Engineering, 2010;33(5):919-933).
For more information, contact D. Ghorbel, Center Urbain Nord, Dept. of Biology & Chemical Engineering, National Institute Applied Science & Technology, BP 676, Tunis 1080, Tunisia.
From the November 15, 2010, Prepared Foods E-dition
