HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Interpretive Summary Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Vignolles, M. L. Articles by Jeantet, R. Search for Related Content PubMed PubMed Citation Articles by Vignolles, M. L. Articles by Jeantet, R.

Fat properties during homogenization, spray-drying, and storage affect the physical properties of dairy powders

M. L. Vignolles^*,, C. Lopez^*,, M. N. Madec^*,, J. J. Ehrhardt, S. Méjean^*,, P. Schuck^*,,1 and R. Jeantet^*,

^* Institut National de la Recherche Agronomique (INRA), UMR1253, F-35000 Rennes, France
Agrocampus Rennes, Unité Mixte de Recherche (UMR) 1253, F-35000 Rennes, France
Centre National de la Recherche Scientifique (CNRS), Nancy-Université, UMR 7564, Laboratoire de Chimie Physique et de Microbiologie pour l’Environnement, F-54600 Villers lès Nancy, France

¹ Corresponding author: Pierre.Schuck{at}rennes.inra.fr

Changes in fat properties were studied before, during, and after the drying process (including during storage) to determine the consequences on powder physical properties. Several methods were combined to characterize changes in fat structure and thermal properties as well as the physical properties of powders. Emulsion droplet size and droplet aggregation depended on the homogenizing pressures and were also affected by spray atomization. Aggregation was usually greater after spray atomization, resulting in greater viscosities. These processes did not have the same consequences on the stability of fat in the powders. The quantification of free fat is a pertinent indicator of fat instability in the powders. Confocal laser scanning microscopy permitted the characterization of the structure of fat in situ in the powders. Powders from unhomogenized emulsions showed greater free fat content. Surface fat was always overrepresented, regardless of the composition and process parameters. Differential scanning calorimetry melting experiments showed that fat was partially crystallized in situ in the powders stored at 20°C, and that it was unstable on a molecular scale. Thermal profiles were also related to the supramolecular structure of fat in the powder particle matrix. Powder physical properties depended on both composition and process conditions. The free fat content seemed to have a greater influence than surface fat on powder physical properties, except for wettability. This study clearly showed that an understanding of fat behavior is essential for controlling and improving the physical properties of fat-filled dairy powders and their overall quality.

Key Words: free fat • structure • spray-drying • powder physical property