Effects of different granule size of shiitake mushroom stipe powder on structural, texture, microstructural, rheological and antioxidant properties of yogurt

This study investigated the effect of adding different granule sizes (300 μm, 200 μm, 150 μm, and 74 μm) of shiitake mushroom stipe powder (SMSP) on the antioxidant, texture, microstructural, and rheological properties of yogurt after 24 h of storage at 4 ºC. The prepared yogurt samples showed that acidity, water holding capacity, and antioxidant activity increased as the granule size of the SMSP decreased. The yogurt’s hardness initially increased and then declined with the addition of finer granules, whereas its apparent viscosity consistently decreased. The microstructure of yogurt with SMSP exhibited compact, homogeneous aggregates similar to plain yogurt. FTIR analysis showed that the –CH and –OH peaks of yogurt was not change significantly (p < 0.05) with adding of different granule sizes of SMSP. Zeta potential (ζ) indicated that charges were reduced significantly (p < 0.05) with addition of smaller granule sizes. Particle size distribution showed a single peak in all yogurt samples, attributed to intermolecular aggregation caused by interactions between SMSP particles and casein. These results demonstrate that the addition of SMSP enhances the quality and overall performance of yogurt.