Stabilizing effect of xanthan gum and sodium alginate on the physicochemical properties and gel structure of walnut-based yogurt

The poor gel property of plant proteins and phase separation restrict plant-based yogurt products. In this study, anionic colloids were evaluated for walnut yogurt production, and sodium alginate (SA) or xanthan gum (XG) greatly improved the overall quality of walnut yogurt. The incorporation of SA or XG at low concentrations (0.5–0.6%) effectively promoted fermentation and significantly increased the total phenolic content in walnut yogurt 1.47 and 1.23 times, respectively, compared to the control group. Concurrently, the water-holding capacity increased approximately 3 times. Both gums also improved the textural and rheological properties of the yogurt, notably increasing the hardness and chewiness. Sensory analysis confirmed that yogurts containing 0.5–0.6% SA or XG received higher overall sensory scores. Notably, SA incorporation could promote the formation of a dense network structure in walnut yogurt, while the XG incorporation could improve for the fermentation process of the yogurts.