Determination of reaction orders for ascorbic acid degradation during sterilization using a new experimental device: The thermoresistometer Mastia®

Sterilization is the most relevant technique to guaranty safety of shelf-stable highly hydrated food products at ambient temperature. However, these thermal processes are often optimised to microbiological aspect and consequently are not without consequences on food quality. Ascorbic acid's degradation at sterilization temperature (>100 degrees C) is poorly documented. Using a new instrumented reactor (thermoresistometer Mastic (R)), the behavior of ascorbic acid was studied in food model solution at pH = 3.5, in aerobic and anaerobic conditions from 95 degrees C to 125 degrees C. In anaerobic conditions, degradation was slow and followed first order kinetics (k(125 degrees C) = 2.88*10(-3) min(-1), E-a = 96 kJ/mop. In aerobic conditions, reactions were faster with total elimination of ascorbic acid in about 4 h, and the data were best fitted using 0.5-order, while reaction speed varied little with temperature. (C) 2016 Elsevier Ltd. All rights reserved.