Thermal and photochemical degradation of carotenoids

C. D. BORSARELLI; A. Z. MERCADANTE

Carotenoids: Physical, Chemical, and Biological Functions and Properties

CRC Press

Lugar: New York; Año: 2010; p. 229 - 253

The most characteristic feature of the carotenoid structure is the presence of several conjugated double bonds in the chain. The polyene chain is responsible for the light absorption properties and also for the susceptibility of carotenoids to degradation under high temperature, low pH, light and reactive oxygen species, amongst other factors. Nevertheless, heat processing has become an important part of the food chain and both processed and fresh foods are often exposed under fluorescent light in supermarkets. Although carotenoids are naturally stabilized by the plant matrix, cutting or disrupting of fruit and vegetable tissues favors their exposure to oxygen and endogenous oxidative enzymes, thus provoking their isomerization and oxidation. Differences between fruit and vegetable species, such as localization of carotenoids in the tissue and its physical state, may be crucial factors for the susceptibility of these pigments to transcis isomerization and oxidation reactions. In food systems, the mechanisms involved in both thermal and photochemical degradation are much more complex than in model systems. Along with the environmental factors and carotenoid structure that play important known roles, the physical state and location in cellular organelles, and interactions between different naturally occurring food compounds are much more difficult to predict. Therefore, comparison of published data regarding the extension of carotenoid degradation is a difficult task since different foods are processed and stored under different combination of temperature, light and time, etc., and such conditions are sometimes only partially described.