Comparative study of particle structure evolution during water sorption: Skim and whole milk powders

Ingrid Murrieta-Pazos (1) , C Gaiani (1) , Laurence Galet (2) , Bernard Cuq (3, 4) , S. Desobry (1) , J. Scher (1)

1 LIBio - Laboratoire d'Ingénierie des Biomolécules
2 RAPSODEE - Centre de recherche d'Albi en génie des procédés des solides divisés, de l'énergie et de l'environnement
3 UMR IATE - Ingénierie des Agro-polymères et Technologies Émergentes
4 Montpellier SupAgro - Institut national d’études supérieures agronomiques de Montpellier

Surface composition of dairy powders influences significantly a quantity of functional properties such as rehydration, caking, agglomeration. Nevertheless, the kinetic of water uptake by the powders was never directly related to the structure and the composition of the surface. In this work, the effect of relative humidity on the structural reorganization of two types of dairy powder was studied. The water-powder interaction for industrial whole milk powder, and skim milk powder was studied using dynamic vapor sorption. The water sorption isotherms were fitted with a Brunner-Emmet-Teller model and each stage of the sorption curve was analyzed with a Fickian diffusion. The water content in the monolayer predicted for each powder and the moisture diffusivity calculated were discussed and compared. Concurrently, powders microstructure and powders surface under variable relative humidity were assessed by X-ray photoelectron spectroscopy, scanning electron microscopy coupled with energy dispersive X-ray and atomic force microscopy. A correlation between the data obtained from the sorption isotherms and the modifications of structure allowed us to conclude that powder microstructure and chemical state of the components could play an important role in determining the water diffusivity.

Mots clés: dairy powder; sorption isotherm; microstructure; surface composition; agglomérant; microstructure des poudres; surface des poudres; sotherme de sorption; milk; water; powder; functional property; dairy product; numerical models; kinetics; rehydration; aggregation; water content

Mots clés: poudre; propriété fonctionnelle; humidité; agglomeration; rehydratation; cinétique; modèle; produit laitier; lait; eau

Domaines: Autre

Ingrid Murrieta-Pazos, C Gaiani, Laurence Galet, Bernard Cuq, S. Desobry, et al.. Comparative study of particle structure evolution during water sorption: Skim and whole milk powders. Colloids and Surfaces B: Biointerfaces, 2011, 87 (1), pp.1-10. ⟨10.1016/j.colsurfb.2011.05.001⟩. ⟨hal-01506074⟩