Identification of Umami Taste in Sous-Vide Beef by Chemical Analyses, Equivalent Umami Concentration, and Electronic Tongue System

Behaviour of umami compounds that are associated with non-volatile compounds on slow cooking regimes remains less explored. This study aims to assess the ability of the electronic tongue system on the umami taste from sous-vide beef semitendinosus. The identification was based on the taste-enhancing synergism between umami compounds 5'-nucleotides (IMP, GMP, AMP, inosine, and hypoxanthine) and free amino acids (glutamic and aspartic acid) using the estimation of equivalent umami concentration (EUC) and electronic tongue system. Sous-vide cooked at 60 and 70 degrees C for 6 and 12 h and cooked using the conventional method at 70 degrees C for 30 min (as control) were compared. The temperature had a significant effect on 5'-nucleotides, but aspartic and glutamic acid were not influenced by any treatments applied. Sous-vide cooked at 60 degrees C tended to have higher inosine and hypoxanthine. Meanwhile, desirable 5'-nucleotides IMP, AMP, and GMP were more intensified at the temperature of 70 degrees C. The principal component analysis predicted a good correlation between EUC and the electronic tongue, with sous-vide at 70 degrees C for 12 h presenting the most umami. Therefore, the electronic tongue system is a useful tool in food processing, particularly in determining complex sensory properties such as umami, which cannot be evaluated objectively.