Effect of Thiamin Oxidation on Thermal Formation of Meaty Aroma Compounds

Abstract

Thiamin (vitamin B₁), a sulfur-containing component, is considered a potential precursor for meat flavor. Thiamin can be oxidized to thiochrome in the presence of oxidants or under basic conditions. Conversion of thiamin to thiochrome stabilizes the chemical structure of thiamin. Hydrogen peroxide effectively converted thiamin to thiochrome at pH 7.0 and 9.5; the conversion rates were 8% and 30%, respectively. Without hydrogen peroxide incubation, the conversion rates were 0.6% and 1% at pH 7.0 and 9.5, respectively. At pH 1.5, the conversion rate was 0% with or without hydrogen peroxide incubation. The formation of thiochrome considerably reduced the yield of thermal degradation compounds. Even though hydrogen peroxide did not convert thiamin to thiochrome at pH 1.5, it significantly changed the volatile profile obtained from thiamin degradation. Thermal degradation of thiochrome at pH 1.5, 7.0, and 9.5 showed that thiochrome is a stable compound and is not a good volatile contributor. These results suggest conversion of thiamin to thiochrome can be achieved in the presence of the oxidant, hydrogen peroxide at neutral to basic conditions. Oxidation can significantly reduce the intensity of volatile compounds derived from thiamin degradation, and consequently, affect the overall flavor of foods