The free amino acid profiling of milk- and cereal-based Kyrgyz ethnic fermented beverages and their contribution to taste formation

Abstract

The present study aimed to determine the content of 18 free amino acids (FAA), including 10 essential amino acids, in traditional fermented beverages and their umami, sweet and bitter taste potential. The FAAs of traditional dairy and cereal-based fermented beverages were measured using high-performance liquid chromatography (HPLC) with a diode array detector and derivatization with diethyl ethoxymethylenemalonate (DEEMM). FAA content and taste attributes with a focus on umami, sweet and bitter were presented for koumiss, ayran, carbonated ayran, boza, boza with sea buckthorn, and maksym. The ratio of free essential amino acids (EFAA) to nonessential (NEFAA) was in the range of 0.41-1.12 except for ayran (0.28), indicating that each type of beverage has a rich source of their respective essential FAA profile. FAA represented 24.68% of the total protein, with the highest value for koumiss. The respective taste property contribution of bitter FAAs was high in koumiss (51%) and carbonated ayran (56%), whereas sweet-tasting FAAs were dominant in jarma (52%). The distribution of taste-active amino acids in the formation of the corresponding tastes was distinct.