Decolorization of β‐Carotene in Model Systems Simulating Dehydrated Foods. Mechanism and Kinetic Principles

The mechanism and kinetic principles of β‐carotene decolorization under reduced oxygen (0–20.9%) low water activity (“dry”– 0.84) and 35°C were investigated in a model system. Oxygen was found to be a crucial factor in β‐carotene degradation. Rate of decolorization due to oxygen was found to be influenced by the amount of oxygen adsorbed. This amount was influenced by oxygen partial pressure and the physical and chemical structure of the adsorbent. β‐Carotene decolorization was found to be strongly affected by the presence of free radical initiators. On the other hand, degradation was slowed down when an antioxidant was added. β‐Carotene retention curves were sigmoidal with three regions, namely, an induction period, a fast “main” period, and a retardation period‐typical of an autocatalytic radical reaction. Water activity was found to play a protective role in β‐carotene decolorization.