Metabolomic and microbiome analysis of Nanmas as a rare Yogurt‑like fermented dairy product with sourdough as a natural starter culture

Ancient inhabitants of Zagros used a unique method to produce a fermented dairy product similar to Yogurt (in the local dialect "Nanmas"), in which wheat sourdough served as a starter. This study scientifically investigated this product and compared it with commercial Yogurt. Comprehensive analysis of physicochemical properties, including pH, titratable acidity, and Syneresis; texture profiling; microbial Viability; NMR based metabolomics; microbiome analysis with 16S rDNA sequencing; and sensory evaluation were performed by a trained team. Compared with commercial Yogurt, Nanmas had lower pH, higher titratable acidity, and less syneresis during storage ( P ≥ 0.05). NMR analysis revealed a qualitatively greater diversity and a wider range of desirable metabolites in Nanmas, which also exhibited a denser texture and more complex flavor profile compared to commercial yogurt. Two strains of Pediococcus acidilactici and Pediococcus pentosaceus were confirmed as the dominant flora, which explains the mechanism of action of the traditional process. Sensory analysis showed that Nanmas scored higher in terms of taste, texture and overall acceptability compared to commercial Yogurt. These findings not only confirm the scientific value of this ancient method, but also demonstrate the high potential of wheat sourdough as a natural and efficient industrial starter alternative.