A novel set-type yogurt with improved rheological and sensory properties by the sole addition of insoluble soybean fiber

With the rise of sustainable concepts, the beneficial role of soluble dietary fiber in the preparation of clean labelled yogurt has been recognized, but the role of insoluble dietary fiber remains controversial. In this work, the effect of insoluble soybean fiber (ISF) on the rheological and sensory properties of yogurt was investigated based on the improved structural and physicochemical properties of ISF. The results showed that ISF improved the rheological properties of yogurt in a positive concentration-dependent manner. The viscoelasticity was enhanced, with ISF contributing more to the elastic component than to the viscous component. The viscoelastic structure of yogurt was found to be less sensitive to temperature and stress variations and exhibited thermal reversibility. These observations were attributed to the skeletal support of the ISF on the 3D network structure, the facilitation of interactions within the yogurt gel matrix by the ISF and the gel-like network structure of the ISF itself. Creep recovery and thixotropic properties were also improved after the addition of ISF. By analyzing the metrics of rheological properties using principal component analysis, it was found that yogurts with moderate concentrations (0.25%–0.75%, w/v) of ISF were similar to some non-clean-labelled commercial yogurts. Of these, the yogurt containing 0.5% ISF exhibited the best sensory properties. This study provides insight into the development of insoluble dietary fiber and the manufacture of high-quality clean-labelled yoghurt.