How surface composition of high milk proteins powders is influenced by spray-drying temperature.
High milk proteins powders are common ingredients in many food products. The surface composition of these powders is expected to play an essential role during their storage, handling and/or final application. Therefore, an eventual control of the surface composition by modifying the spray-drying temperature could be very useful in the improvement of powder quality and the development of new applications. For this purpose, the influence of five spray-drying temperatures upon the surface composition of the powders was investigated by X-ray photoelectron spectroscopy. The major milk proteins were studied: native micellar casein and native whey, both more or less enriched in lactose. The results show a surface enrichment in lipids for all the powders and in proteins for many powders. Whatever the drying temperature, lipids and proteins are preferentially located near the surface whereas lactose is found in the core. This surface enrichment is also highly affected by the spray-drying temperature. More lipids, more proteins and less lactose are systematically observed at the surface of powders spray-dried at lower outlet air temperatures. The nature of proteins is also found essential; surface enrichment in lipids being much stronger for whey proteins containing powders than for casein containing powders. Additionally, we found a direct correlation between the lipids surface concentration and the wetting ability for the 25 powders studied.
Gaiani
C
C
LIBio, Nancy Université, Laboratoire d'Ingénierie des Biomolécules, 2 avenue de la Forêt de Haye, B.P. 172, 54505 Vandoeuvre Les Nancy Cedex, France. claire.gaiani@ensaia.inpl-nancy.fr
Morand
M
M
Sanchez
C
C
Tehrany
E Arab
EA
Jacquot
M
M
Schuck
P
P
Jeantet
R
R
Scher
J
J
D000818:Animals; D002417:Cattle; D004602:Elements; D007785:Lactose / Q000737:chemistry; D008055:Lipids / Q000737:chemistry; D008894:Milk Proteins / Q000737:chemistry*; D010316:Particle Size; D056951:Photoelectron Spectroscopy; D011208:Powders; D025341:Principal Component Analysis; D011489:Protein Denaturation; D020836:Protein Structure, Quaternary; D012015:Reference Standards; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D013696:Temperature; D017155:Wettability; D000067816:Whey Proteins
D004602:Elements; D008055:Lipids; D008894:Milk Proteins; D011208:Powders; D000067816:Whey Proteins; D007785:Lactose