2015 Volume 110 Issue 8 Pages 591-598
For the analysis of total amino acid levels in sake, a method using deleterious formalin, namely formaldehyde aqueous solution, has been adopted in the National Tax Agency: the prescribed analysis method (NTA method). After neutral amino acids react with formaldehyde, they become acidic, then to be titrated using the alkaline solution. In recent years in Japan, formaldehyde cannot be used without local exhaust ventilation systems, such as fume hoods. Therefore, we have studied the method without formalin. When we used ethanol instead of formalin in the NTA method, the titration values showed a high correlation with the amino acid level as determined by the NTA method. Because the ethanol additional method uses almost the same instruments and operations as the NTA method, it can be expected to be utilized in sake industries.
