Stability of capsaicinoid content at raised temperatures

Capsaicinoids, found in the fruits of Capsicum species, contribute to the spiciness of foods. However, the fruits are often subjected to heat, particularly during food preparation and in other high temperature operations, and possible changes in the capsaicinoid content have not been systematically reported. Therefore, this investigation focused on the effects of initial concentration, temperature, time and pH on the final capsaicinoid content in a model system. With higher initial concentrations (200-1000 ppm) of capsaicinoids to start with, the reduction rates were slower as the heating time increased. Under a constant initial capsaicinoid concentration (200 ppm), neutral pH had a lower rate of change in capsaicinoid content than that of both alkaline and acidic conditions. Also, alkaline conditions were more stable than acidic. The rate of reduction was generally much faster at higher temperatures, no matter what the initial concentration. Apparently, to retain a high content of capsaicinoids at the end of heating at high temperature, a high initial concentration is necessary, as well as maintaining at neutral pH and having a short heating time.