Degradation Kinetics of Thiamine in Aqueous Systems at High Temperatures

Abstract

High temperature thermal destruction kinetics of thiamine (Bl) were studied in water and in an aqueous mixture of thiamine, ascorbic acid and Maillard color forming compounds glucose and glycine. The thiamine content of test samples sealed in glass ampoules and capillary tubes subjected to various time-temperature treatments was analyzed by HPLC. The study indicated that the two sample heating techniques (ampoule and capillary) were comparable; the destruction of thiamine could be described by first order reaction rate kinetics, and the destruction behavior was dependent on the presence of other compounds (ascorbic acid and color precursors). The activation energy and reference rate constant (ko) at 121.1°C for thiamine destruction using the Arrhenius approach ranged from 103–118 kj/mole and 0.0060-0.0067min1 in water, and 71.1–73.4 kj/mole and 0.0066-0.0069min 1in the mixture, respectively. Similar analyses using the TDT approach yielded z and Dovalues of 26.4–30.6 C° and 350–394min in water and 42.4-43.8 C° and 338–354min in the mixture, respectively.