Effects of partial coconut flour fortification and butter reduction with pumpkin puree in rice donuts

Coconut flour is rich in dietary fiber and protein, is lower in calories, and has a lovely tropical aroma than rice flour. At the same time, plant-based fat replacers, such as fruit and vegetable puree, which can provide moisture, thickening properties, and lower calories than fat, are popularly used in low-fat baked products. Thus, a reduced-butter gluten-free rice donut with coconut flour has been developed for people with celiac disease. This study evaluated the effect of different coconut flour levels (0%, 10%, 20% and 30% (w/w)) for rice flour in donuts under all-butter and reduced-butter (butter /  pumpkin puree = 75 /25 w/w) conditions. The experimental results were subjected to a two -way analysis of variance, and principal component analysis was used for perceptual mapping. The physical properties assessed were specific volume, firmness, L*, a*, and b*, while a 9-point hedonic scale was used for sensory evaluation. Incorporating 10% to 30% coconut flour significantly decreased the specific volume but increased firmness, L*, a*, and b*, in all-butter and reduced-butter conditions. Rice donuts with 10% coconut flour received higher scores for sensory perception than those made with 20% and 30% coconut flour. Replacing 25% of the butter with pumpkin puree improved some sensory attributes such as color, flavor, and texture. The optimal formulation was the rice donut fortified with 10% coconut flour in the reduced-butter condition.