Improving the technological properties of whole and skimmed symbiotic yogurts supplemented with fructooligosaccharides and Cassia grandis seed galactomannan

Although yogurt is an excellent vehicle for incorporating functional ingredients, its production still faces technical challenges, including syneresis, rheological instability, and reduced microbial stability during prolonged storage. This study aimed to evaluate the impact of galactomannan from Cassia grandis seeds (0.2% w/v), combined with fructooligosaccharides (FOS) (1% w/v), on the physicochemical and functional properties of whole and skimmed milk yogurts. Galactomannan and FOS concentrations were selected based on preliminary studies as their synergism stabilized the yogurts´ casein network, thus resulting in lower whey separation. Samples were monitored for pH, acidity, color, syneresis, water holding capacity (WHC), texture profile, and rheological behavior. Data were subjected to analysis of variance (ANOVA), and means were compared by Tukey's test (p < 0.05). The incorporation of additives significantly reduced syneresis by 14.68% and increased WHC by 14% compared to the control. Firmness increased by 1.45 g in supplemented yogurts when compared to the control, providing a more robust matrix without compromising sensory acceptance or microbiological safety (p > 0.05). These findings demonstrate that the synergistic effect of GCg and FOS favors a denser network and a more cohesive gel, thus validating the potential of the C. grandis galactomannan as a stabilizing agent. Finally, the use of GCg and FOS can be promoted at the industrial level to improve shelf life and functional appeal in dairy products. However, further studies are required to optimize protein content, ensure probiotic viability during storage, and estimate large-scale production costs.