Gamma irradiation-induced degradation of dehydroacetic acid and sodium dehydroacetate in aqueous solution and pear juice

Gamma irradiation can be performed alone or in combination with other preservatives such as dehydroacetic acid (DHA) and sodium dehydroacetate (DHA-Na) to achieve an enhanced level of food safety. Here, we studied the effect of gamma irradiation on the stability and degradation of DHA and DHA-Na in aqueous solution and pear juice. The degradation rate of DHA and DHA-Na was found to increase with increasing irradiation time and decreasing initial solute concentration in aqueous solution. The degradation rate of DHA-Na was higher than that of DHA under the same irradiation conditions. The degradation process of DHA and DHA-Na followed first-order reaction kinetics. The main radiolytic product of DHA and DHA-Na was identified as heptane-2,4,6-trione by GC-MS/MS, and the possible degradation pathway was proposed. Quantum chemical calculation results further confirmed that DHA-Na was much easier to be degraded than DHA. In addition, radiolytic degradation of DHA-Na happened in pear juice, but with a much lower degradation rate than that in aqueous solution.