Session: General Poster:

Metabolomics is a systematic analysis of small molecules such as amino acids, tricarboxylic intermediates, and fatty acids in a biological system. Quantification of metabolites provides a real-time snapshot of reactions in a biological system. Yogurt is a fermented dairy product and possesses many health benefits. Characterizing metabolites and changes in their concentration during the storage of yogurt would provide a comprehensive understanding of the technological process used for its manufacturing. The objective was to determine overall changes in the metabolite profiles of cow milk yogurt (CY) and goat milk yogurt (GY) during storage. Yogurt culture (Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus) was incoluated at 20 DCU/100 liters of milk. Yogurt samples were stored in polystyrene cups for at refrigeration temperature. The samples were analyzed using a GC-MS based untargeted metabolomics at different storage intervals (day 0, 14, and 28). The metabolites were identified using NIST 17 library, and the mass spectral data were analyzed using R-programming and MetaboAnalyst. Metabolomics analysis indicated 187 compounds in CY and GY. The principal component analysis noted different clusters of metabolites present in between CY and GY on day 14. Upregulation (p < 0.05) of free amino acids and dipeptides in GY indicated a stronger proteolytic action of bacteria on goat milk proteins, while tri-peptides were upregulated (p < 0.01) in CY, revealing its better texture. The predominance of medium-chain fatty acids in GY resulted in the upregulation (p < 0.05) of carboxylic acids and fatty acid derivatives on day 14. Impact pathway analysis showed the association of differentially abundant metabolites of GY with metabolic pathways of amino acids. This work will provide novel insights into the metabolite differences between yogurt prepared from large (cow) and small ruminant (goat) milk and help researchers comprehend key factors in improving yogurt composition and nutrition.

Dr Ranjith Ramanathan

Associate Professor, Oklahoma State University

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