ISBN 9783843954969

978-3-8439-5496-9, Reihe Lebensmitteltechnologie

Daniel Tritschler
Formation of micro- and macrobubbles in dairy matrices – Textural effects and application as fat replacer

165 Seiten, Dissertation Universität Hohenheim Stuttgart-Hohenheim (2024), Softcover, A5

Zusammenfassung / Abstract

The reduction of fat and the successful introduction of fat replacers in food formulations is a challenging task. For the successful application of gas bubbles, the influence of bubbles on the textural and sensory properties were investigated. Stiffness, yield stress, apparent viscosity and the friction coefficient were chosen for the textural characterization.

One focus of this work was the reproduceable formation of microbubbles. This was achieved by the optimization of the foaming process and the subsequent stabilization of the gas bubbles. Important factors for the foaming process were a 2:1 ratio of mass and gas flow and a high rotational speed of the mixing head. The highest bubble stabilization was achieved by the addition of 1 % cream. During the analysis, a critical gas volume fraction above which the texture becomes weaker, could be detected. This critical fraction depends on the total particle concentration of the matrix. As particles in a system influence 1.5 times of their own volume, the maximal addable concentration is 40 %. Above this concentration, particle interactions occur causing a loss of free rotation and deformability of the bubbles. However, these factors are essential to prevent the bubbles from bursting under shear.

Contrary to the results of the textural analysis, the matrix with 5 % gas achieved the highest creaminess ranking in the sensory study. Evidently, it is more important to introduce only small amounts of gas, even if the texture was not as much enhanced as it was for 23 % gas. If too much gas is added, the product is perceived as airy and not creamy anymore.