PURPOSE: To make it possible to apply the measuring method on manufacturing process for processed food and drink products without trouble by adding orthophenylenediamine for reaction after the addition of a buffer container to the food and drink, pH adjustment and deoxidation treatment, and shortening the measuring time of diacetyl.
CONSTITUTION: For example, a part of tomato juice is sampled in the final stage of the manufacturing process of the tomato juice Briton-Robinson buffer or the like of 96ml is added into distilled initial boiling of 4ml, and the pH is adjusted to 5.0. Nitrogen gas is made to pass through this adjusting liquid. In the liquid wherein dissolved oxygen is removed, orthophenylenediamine is added so as to obtain the concentration of about 5ppm, and reaction is made to occur. The reacted liquid is supplied into differential pulse voltammetry, and the peak current value is read. The value is compared with the already formed calibration curve, and the diacetyl concentration is measured. Thus, the measurement up to the diacetyl concentration of about 0.08ppm can be performed. The reproducibility of the measured value is excellent, and the required measuring time can be shortened to about 1/4 or less.
HAYAKAWA YOSHIO
YAMADA YASUNORI
