Thermal Destruction of Vitamin B6 Vitamers in Buffer Solution and Cauliflower Puree

Abstract

ABSTRACT Thermal degradation rates of pyridoxal (PL‐HCl), pyridoxine (PN‐HCl) and pyridoxamine (PM‐2 HCl) in 0.1 M phosphate buffer (pH 7.20) were determined over the temperature range 110‐145°C using HPLC procedures. Thermal degradation of PM‐2 HCl was modelled by a pseudo‐first order rate constant. Thermal degradation of PN‐HCl and PL‐HCl was modelled by a 1.5 order and second order model, respectively. The temperature dependence of all three rate constants could be described by the Arrhenius equation. None of the degradation products from any of the vitamers exhibited antivitamin activity. Thermal degradation rates of vitamin B6 in cauliflower puree were measured over the temperature range 106‐138°C and found not to be described by a first‐order model. The activation energy was markedly lower in this food system than in the model system and emphasizes the importance of conducting experiments on real food systems. The activation energy is in the range reported for several other water soluble nutrients.