Enhancement of protein structure-forming properties in liquid foams by spray drying

Autor: Perla Relkin, Pablo Granda, Jean Vasseur, Bertrand Broyart, Clemence Bernard
Rok vydání: 2008
Předmět:
Zdroj: Dairy Science & Technology
Dairy Science & Technology, EDP sciences/Springer, 2008, 88 (1), pp.65-80
ISSN: 1958-5594
1958-5586
Popis: In the first part of this study we used mathematical modelling for prediction of hydrothermal pathways (time evolution of temperature and water content) of a whey protein-rich product during its spray drying in a co-current configuration. The model was validated through drying assays, where the inlet/outlet air temperatures were fixed at 170/85 °C, 217/107 °C, 247/125 °C or 260/138 °C, the other spray-drying operation variables being unchanged. Then, the spray-dried powders were characterised before and after re-hydration for evaluation of a threshold air operating temperature value leading to changes in protein structure-functionality, in comparison with the nonspray-dried protein solution (WP-L). The predicted hydro-thermal pathways of the whey proteinrich product during its spray drying indicated that all of the operation variables used were accompanied by a product wet bulb temperature value lower than 60 °C. However, the resulting powders presented different internal porosity and wall thickness, and the protein solutions obtained after the powders’ re-hydration behaved differently from the non-spray-dried protein solution (WP-L). Particularly, it seemed that powders obtained at outlet air temperature and water content higher than 100 °C and lower than 4%, respectively, presented a higher internal porosity and lower free lactose content. Furthermore, they were accompanied by lower protein solubility and conformation stability and by a slight development of hydroxymethylfurfural and covalently-bound protein aggregates. In addition, in situ evaluation of foam formation and stability after air injection into the re-hydrated powders showed that increasing spray-drying air temperatures led to powders with more and more enhanced foaming properties, relative to the whey protein-rich solution before spray drying. The powder characteristics obtained in the present study, added to those recently published [Relkin et al., Lait 87 (2007) 337–348] are presented and discussed in regards to effects of spray-drying operation variables on protein structural changes and enhancement of foaming properties without additional processing equipment.
Databáze: OpenAIRE
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