Characterization of volatile compound profile in Mongolian traditional fermented mare's milk, as Airag

We aimed to evaluate the volatile compounds profile in traditional airag samples collected from two regions, including Bulgan and Uvurkhangai provinces, whereas famous airag-making areas in Mongolia. The volatile compounds of airag were investigated by the GC-MS method. A total of 95 kinds of volatile compounds were detected, and these were classified into 6 different classes: 14 acids, 14 alcohols, 16 aldehydes, 19 esters, 9 ketones, and 23 aliphatic hydrocarbons. Among them, acetic acid, 2-methyl propionic acid, isoamyl lactic acid, 2-methyl butanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, n-decanoic acid, 1-propanol, 3-methyl 1-butanol, phenyl ethyl alcohol, acetaldehyde, acetoin, ethyl acetate, ethyl hexanoate, ethyl caprylate, ethyl decanoate, ethyl 9-decanoate, and ethyl laurate had a high concentration in airag samples. It may explain that acids, alcohols, and esters mainly influence the taste and aroma of airag, and aldehydes change depending on their fermentation time. We also found that Bulgan provinces` samples contained 20 types of aliphatic hydrocarbons, which may relate to the vegetation and fermentation process. The formation of sensory characteristics in airag is a complex and unclear process because it affects many factors. Our findings provide essential guidance on the composition of volatile compounds in Mongol airag.