2009 Volume 15 Issue 5 Pages 491-498
The taste, as well as odor, of hindered phenols which are commonly used as antioxidants for olefin polymers of cup-type vending machine for beverages was investigated to identify the cause of the increasing unpleasant taste of beverages with free chlorine added in the source water for sterilization. The threshold concentration of solutions of mono- and di-substituted hindered phenols were confirmed to decrease due to free chlorine, while that of tri-substituted hindered phenols with substituents at the 2, 4, and 6 positions were not affected by free chlorine. The magnitude of the decrease in the threshold concentration depended on the number of free 2, 4, and 6 positions on the aromatic ring. The products formed by chlorination, oxidation, ring opening and dimerization of the hindered phenols were identified by GC/MS in the model reaction with free chlorine. Based on the threshold concentrations of some identified products, their effects on the increasing unpleasant taste were estimated.
