Abstract:
To elucidate the relationship between the structure of wax-based oleogels and bread quality, this study examined the effects of varying cooling temperatures (20, 4, −18 ℃) on the crystalline network structure of rice bran wax (C24-C32)—high oleic sunflower oil-based oleogels. Additionally, the application of these oleogels in bread was evaluated by substituting margarine with equal amounts of oleogels prepared with 3%, 5%, 8%, and 10% rice bran wax under 20 ℃ cooling. The results pertaining to the microstructure, crystal polymorph, oil-holding capacity, hardness, and thermal properties of the oleogel demonstrated thatt oleogels cooled at 20 ℃ exhibited a dense dendritic crystalline network with the presence of
β' polymorphs. Elevated cooling temperatures increased the fractal dimension Db values (1.822±0.013~1.835±0.105). As the rice bran wax content increased, the crystalline network of oleogels became progressively denser, accompanied by significant increases (
P<0.05) in Db values (1.053±0.104~1.783±0.023), hardness (49.40~98.13 g), and oil-holding capacity (93.35%~98.05%). Correspondingly, the melting/crystallization peak temperatures increased gradually. Fourier transform infrared spectroscopy confirmed the existence of van der Waals forces among the oleogel constituents. In relation to dough hardness and rheological properties, the hardness of doughs prepared with the oleogels was comparable to that of the butter-containing dough, while both the storage modulus (G') and loss modulus (G'') were lower than those of the butter-based dough. The oleogel containing 10% rice bran wax displayed a significantly higher relative content of
β' polymorphs than other groups (
P<0.05), and the resultant bread showed texture properties, specific volume, and crumb structure approaching those of the butter-containing bread. The
L*,
a* , and
b* values of the crust color for all oleogel-added breads were lower than those of the butter-containing bread, with minimal impact on the crumb color. In summary, the dense crystalline network structure and high
β' polymorph content in wax-based oleogels are critical factors influencing bread quality.