Rheological behavior of fermented camel and bovine milk as investigated by microstructural and fractal analyses

This study aimed to compare the microstructure, texture, and rheological properties of fermented camel milk (CM) and bovine milk (BM) fermented with a mixture of Streptococcus thermophilus and Lactobacillus bulgaricus subsp. delbrückii for 6, 12, and 24 h. Fermented CM showed slower acidification, reduced hardness and cohesiveness, higher syneresis, and a more open and porous microstructure than fermented BM. Amyloid fibrils, β-sheet–rich protein aggregates that exhibited increased intensity with extended fermentation time, were detected in both fermented camel milk (CM) and bovine milk (BM), as well as in their separated whey fractions, with higher levels observed in CM-derived samples. Fermented CM samples exhibited lower fractal dimensions than fermented BM consistent with weaker gel network (lower storage (G′) and loss (G″) moduli and higher tan δ values). Our findings suggest that the gel strength and structural stability of fermented camel milk relative to fermented bovine milk are primarily attributable to differences in protein aggregation and microstructural organization.