Ferreira J E M, Rodriguez-Amaya D B
Dept. of Food Science, Faculty of Food Engineering, Univ. of Campinas- UNICAMP, P.O. Box. 6121, 13083-862 Campinas, S.P., Brazil.
J Food Sci. 2008 Oct;73(8):C589-94. doi: 10.1111/j.1750-3841.2008.00919.x.
Being highly unsaturated, carotenoids are susceptible to isomerization and oxidation during the processing and storage of food. In the present study, the degradation of acyclic lycopene and dicyclic beta-carotene in low-moisture and aqueous model systems, as well as in lyophilized guava, during storage at ambient temperature, in the absence or presence of light, was investigated. Both carotenoids followed first order kinetics under the various conditions investigated. Lycopene degraded much faster than beta-carotene in all the model systems. In a comparison of lycopene isolated from guava, tomato, and watermelon, greater losses were observed with lycopene from tomato. Since the model system was identical in the 3 cases, these results indicated that other compounds from the food sources, co-extracted with lycopene, might have influenced the oxidation. Light consistently and strongly promoted degradation under all conditions studied. The susceptibility of lycopene to degradation was much less in lyophilized guava than in the model systems, showing the marked protective influence of the food matrix. Loss of beta-carotene, found at a concentration of about 18 times lower than lycopene, was only slightly lower than that of lycopene in lyophilized guava, indicating that the effect of matrix and/or the initial concentration overshadowed the structural influence.
由于高度不饱和，类胡萝卜素在食品加工和储存过程中易发生异构化和氧化。在本研究中，研究了在环境温度下，在有或无光照的情况下，无环番茄红素和二环β-胡萝卜素在低水分和水性模型体系以及冻干番石榴中的降解情况。在所研究的各种条件下，两种类胡萝卜素均遵循一级动力学。在所有模型体系中，番茄红素的降解速度都比β-胡萝卜素快得多。在比较从番石榴、番茄和西瓜中分离出的番茄红素时，发现番茄中的番茄红素损失更大。由于这三种情况下的模型体系相同，这些结果表明与番茄红素共提取的食物来源中的其他化合物可能影响了氧化。在所有研究条件下，光照均持续且强烈地促进了降解。冻干番石榴中番茄红素的降解敏感性远低于模型体系，表明食物基质具有显著的保护作用。β-胡萝卜素的损失量约为番茄红素浓度的18倍，在冻干番石榴中仅略低于番茄红素，这表明基质效应和/或初始浓度超过了结构影响。
