Mechanical properties of milk protein skins layers after drying: understanding the mechanisms of particle formation from whey protein isolate and native phosphocaseinate

Autor: Yannick Fallourd, Ludovic Pauchard, Céline Sadek, Cécile Le Floch-Fouéré, Nicolas Pradeau, Pierre Schuck, Romain Jeantet
Přispěvatelé: Science et Technologie du Lait et de l'Oeuf (STLO), Institut National de la Recherche Agronomique (INRA)-AGROCAMPUS OUEST, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Fluides, automatique, systèmes thermiques (FAST), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), United Pharmaceuticals SAS
Jazyk: angličtina
Rok vydání: 2015
Předmět:
Zdroj: Food Hydrocolloids
Food Hydrocolloids, Elsevier, 2015, 48, pp.8-16. ⟨10.1016/j.foodhyd.2015.01.014⟩
ISSN: 0268-005X
1873-7137
Popis: The spray drying of milk proteins usually leads to dry particles of which the final shape can influences physical and functional properties of powders. The aim of this study was to understand the mechanisms of particle formation by considering the mechanical properties of materials making up the two main classes of milk proteins: whey proteins and casein micelles. The progressive solidification of the interface of the droplet during drying time was studied by high speed camera and fluorescence microscopy, in different experimental conditions. The mechanical properties of the final protein materials were then characterized by micro indentation testing. The drying dynamics of whey protein and casein micelle droplets showed different timescales and mechanical lengths, whatever the drying conditions and the droplet configurations, leading to typical mechanical instability at the surface i.e. buckling and fracture. The interface of casein micelles reached sol–gel transition earlier estimated at around 156 g.L −1 following by elastic and plastic regimes in which the shell distorted and buckled to form a final wrinkled particle. In contrast, the interface of whey proteins became elastic at only half the drying time estimated at around 414 g.L −1 , retaining a spherical shape, which finally fractured at the end of drying. The mechanical difference between the two plastic shells might be explained by the behaviour of proteins in jamming conditions. Analogous behaviour could be discussed between the casein micelles and soft and deformable colloids on the one hand, and between whey proteins and hard spheres on the other.
Databáze: OpenAIRE
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