Changes in physical and biochemical properties of spray dried camel and bovine milk powders.
Résumé
This study aimed at investigating the changes in skim camel milk (SCMP) and skim bovine milk (SBMP) powders
produced by spray-drying. The physical (sorption isotherms at 25 °C and the glass transition temperature Tg at
0.13, 0.23 and 0.33 of water activities (aw)) and the biochemical (LC-MS, before and after drying) properties
were assessed. Compared to SBMP, the results for SCMP indicated lower protein denaturation extent, lower
critical aw for lactose crystallization (aw = 0.60 instead of 0.70), and lower Tg at 0.13 of aw (54.6 ± 1.4 °C
instead of 57.8 ± 0.4 °C). Fitted to Guggenheim, Anderson and De Boer (GAB) model, the water sorption
isotherms showed that both powders exhibited the same monolayer moisture content (Xm = 2.0 g 100 g−1,
p > 0.05). These findings were linked to the absence of β-lactoglobulin, the high surface lactose content, the
high initial lactose crystallization and the low size distribution (d50 < 10 μm) of SCMP.
