Effect of Solid-to-liquid Fat Ratio on the Structural and Thermal Properties of Oat Milk-Based Frozen Desserts

Plant-based frozen desserts have gained increasing attention as sustainable alternatives to traditional dairy products. However, the optimization of the fat composition to achieve desirable structural and sensory properties remains a major challenge. The objective of this work was to examine the influence of adding cocoa butter and coconut oil mixed with sunflower oil at 60:40, 70:30, and 80:20 solid-to-liquid fat ratios (w/w) on the physicochemical, structural, and thermal characteristics of oat-based frozen desserts. The formulations were assessed for overrun, melting behavior, hardness, Destabilized Fat Index (DFI), and fat globule size distribution. The quality of the product was strongly influenced by the type of fat and by the solid-to-liquid ratio. The cocoa butter formulations had higher overrun, better resistance to melting, and greater structural stability than the coconut oil formulations. The 80:20 ratio exhibited the highest overrun (80.22 ± 0.53%), longest first dripping time (840 ± 5.3 s), and lowest melting rate (0.13 ± 0.01 g min^{- 1}), whereas the 70:30 formulation provided a more balanced combination of structural and textural properties, with 75.29 ± 0.62% overrun, a first dripping time of 600 ± 5.71 s, a melting rate of 0.17 ± 0.01 g min^{- 1}, and moderate hardness (26.56 ± 2.10 N). These findings demonstrate that controlling the solid-to-liquid fat ratio can influence the structural integrity and melting stability of oat-based frozen desserts. The cocoa butter-sunflower oil 70:30 ratio showed potential as a representative fat system for developing plant-based frozen desserts with a balanced combination of structural and textural properties. PRACTICAL APPLICATIONS: This study demonstrates that optimizing the ratio of solid and liquid vegetable fats can influence the texture and melting resistance of oat-based frozen desserts. The findings provide practical guidance for food manufacturers developing plant-based frozen desserts with desirable quality attributes while reducing reliance on dairy ingredients. These results may support the formulation of vegan frozen desserts with desirable structural stability.