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

Abstract

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.