Effect of Type of Flour and Microalgae (Chlorella vulgaris) on the Rheological, Microstructural, Textural, and Sensory Properties of Vegan Muffins

Abstract

The aim of this study was to develop a recipe for vegan muffins using wheat flour (100%) and a blend of whole-grain spelt flour (50%) and wheat flour (50%) enriched with microalgae (0, 0.5, 1.0, and 1.5% (g/100 g flour)). Replacing wheat flour with whole-grain spelt flour and adding microalgae while eliminating egg white from a recipe can affect the rheological properties of the dough and also the microstructure and texture of the muffins. The study analyzed the effects of the type of flour and the addition of microalgae on the rheological properties of the raw dough, measured through the oscillatory method, as well as the texture and microstructure, determined via X-ray microtomography. Additionally, the sensorial quality of the muffins was analyzed. The use of spelt flour in the formulation of muffins affected the rheological properties of the dough irrespective of the addition of microalgae. The dough made with spelt flour exhibited higher viscosity (consistency coefficient (K) was 74.7 Pa·sn), but it was more cohesive and less springy compared to the dough made with wheat flour alone, which had a K = 58.3 Pa·sn. Incorporating a mixture of spelt and wheat flour along with a 1.5% addition of microalgae made the dough more viscous (K = 118.6 Pa·sn), leading to a fine, porous microstructure (porosity was 69.7%) and a crumbly texture (hardness was 52.2 N) in the muffins. On the other hand, the wheat flour dough with 1.5% microalgae had a consistency coefficient of 69.3 Pa·sn, while the muffin porosity was 67.1% and the hardness 61.8 N. The microstructure had a strong effect on the texture of the muffin crumb. The new wheat flour products with microalgae exhibited a higher proportion of closed pores in their microstructure, whereas samples containing spelt flour and microalgae showed the opposite trend, with more open pores. The greatest difference in closed pores was observed with the addition of 1.5% of microalgae (33.4% in wheat muffins and 26.9% in spelled muffins). The presence of closed porosity contributed to the harder and less consistent texture observed in the muffins. However, despite the instrumental evaluation results, all the new products were accepted by consumers in terms of appearance, taste, and overall quality.