Microbiome-mediated flavor development in Berbassa: a traditional fermented milk starter for Gergoush production

Berbassa is a traditional fermented milk starter used to produce Gergoush, a dry snack that is popular in the dryland regions of Sudan. The unique flavor of Gergoush primarily depends on the spontaneous anaerobic fermentation of milk by natural microbiota following the addition of legumes. Therefore, this study aimed to investigate the microbial communities and volatile compounds in Berbassa prepared using chickpeas and cumin. The microbial community and volatile compounds in the non-fermented milk and Berbassa samples were analyzed using high-throughput sequencing and GC-MS, respectively. The bacterial community in Berbassa samples was dominated by Bacillus (31.52-53.37%) and Clostridium sensu stricto 1 (17.58-57.03%), followed by Paenibacillus, Brevibacillus, and Paraclostridium. In contrast, most fungal genera remained unidentified, followed by Trichosporon, Nothophoma, Alternaria, Aspergillus, and Mortierella as the most prominent identified genera. Fifty-seven compounds were detected by GC-MS, including esters, aldehydes, acids, ketones, alcohols, and phospholipids. Correlation analysis revealed that Bacillus, Clostridium sensu stricto 1, Paraclostridium, Phoma, and Piloderma were significantly correlated with several volatile compounds detected in Berbassa samples. Among these, several compounds are well-known for their strong flavors. The findings suggest a potential connection between the dominant genera Bacillus and Clostridium and the detected volatile compounds, which may contribute to the pungent flavor of Gergoush. This study provides valuable insights for future research on the contribution of individual strains to the unique flavor of Berbassa.