A Sensitive Qualitative Color Test for Residual Hydrogen Peroxide in Foods.

A sensitive qualitative color test for residual hydrogen peroxide (H2O2) in foods treated with H2O2 was investigated. Color tests using peroxidase and 11 kinds of chromogenic reagent and peroxide test strip were compared and evaluated for coloration of color reagents blank and detection sensitivity of H2O2 in the standard solution and in 3 kinds of food. The color test using N-ethyl-N-(2-hydroxy-3-sulfopropyl)-m-toluidine (TOOS)-4-aminoantipyrin (4AA) was most suitable for the qualitative test. A qualitative color test using TOOS-4AA is as follows : 5 ml of a color reagent containing peroxidase, TOOS-4AA and potassium bromate was added to 5 g of the minced sample, and this mixture I was stood for 5 min with occasional shaking. On the other hand, 0.5 ml of the catalase solution and 3.5 ml of the chromogenic solution containing TOOS-4AA were added to 5 g of the same minced sample, and this mixture II is stood for 5 min with occasional shaking. After standing, 0.5 ml of the peroxidase solution and 0.5 ml of the potassium bromate solution were added to the mixture II, and shaken for 10 s. The mixtures I and II were filtered through absorbent cotton. The presence of H2O2 in the sample was judged from the difference between colorations in the both filtrates. Hydrogen peroxide in 13 kinds of food was all negative by the qualitative color test using TOOS-4AA, and detection sensitivity for added H2O2 in those foods was 0.1 or 0.2 μg/g. These results suggested that the qualitative color test using TOOS-4AA could detect a trace amount of residual H2O2 in 13 kinds of food.