Improving sensory quality and properties of stirred high-protein yogurts with a rotor/stator device

This study investigated the impact of post-fermentation processing and fat content on the quality of stirred high-protein yogurts (6 wt% protein) during 13 weeks of storage. A rotor/stator device was used to apply two post-fermentation treatments (119W and 296W, 290 L^-1h) to yogurts containing 0 or 3 wt % fat, while a control yogurt did not undergo post-fermentation processing. Sensory quality was analyzed by Quantitative descriptive analysis (QDA) and Quality control (QC). QC results showed significant effects of post-fermentation processing on appearance, consistency, and odor/flavor. Post-fermentation processing significantly reduced whey separation, stickiness, thickness, sticky mouthfeel and mealiness, and increased shininess and smooth mouthfeel according to QDA results. Confocal laser scanning microscopy and darkfield microscopy revealed larger protein aggregates in the control samples compared to the post-processed samples. The post-processed yogurts maintained acceptable quality after 13 weeks of storage, contrasting with the control samples that had unacceptable quality throughout the storage period.