Effects of freezing on the pigment content in gereen beans and padron peppers
1997
Oruna-Concha, M.J. | Gonzalez-Castro, M.J. | Lopez-Hernandez, J. | Simal-Lozano, J.
The amounts of chlorophylls a and b, beta-carotene and lutein in green beans, blanched green beans and Padron peppers, all frozen at -22 deg. C, were monitored over 12 months by reverse-phase, gradient HPLC (C18 column, visible detection). In unblanched beans, these amounts of the pigments decreased considerably during month 1, but were generally stable during the next 11 months (beta-carotene content decreased further in month 2 before stabilizing). Similar results were obtained for blanched beans, but decreases were offset by increases due to blanching (carotenoids) and lipoxygenase deactivation (beta-carotene), or enhanced by blanching-induced decreases (chlorophylls). In contrast, the amounts of pigments in frozen Padron peppers fluctuated around more or less constant values over the 12 months. Freezing in bags sealed under vacuum lead to moderate decreases in chlorophyll a in Padron peppers and in beta-carotene in blanched green beans.
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