Toivonen PM, Sweeney M
Agriculture and Agri-Food Canada, Pacific Agri-Food Research Centre, Summerland, British Columbia V0H 1Z0, Canada, and British Columbia Ministry of Agriculture, Fisheries and Food, Abbotsford, British Columbia V3G 2M3, Canada.
J Agric Food Chem. 1998 Jan 19;46(1):20-24. doi: 10.1021/jf970490n.
Two broccoli cultivars which have been previously found to have large differences in yellowing susceptibility were studied to determine if there was a relationship between antioxidant capability and chlorophyll loss at a simulated retail display temperature. Greenbelt cultivar retained a stable chlorophyll content over 4 days at 13 degrees C, while Emperor cultivar showed a constant decline in chlorophyll content. These differences were not related to differences in water loss. Superoxide dismutase (SOD) and peroxidase (POD) activities were approximately 30% higher in Greenbelt than in Emperor. The ratio of superoxide dismutase to peroxidase activity was also lower in Greenbelt. The susceptibility of Emperor to oxygen radical damage and lipid peroxidation is expected to be higher since an excessive SOD activity, with respect to POD activity, can potentially lead to enhanced hydroxyl radical formation. Catalase (CAT) activity was higher in Emperor, suggesting that catalase is not important in providing resistance to chlorophyll loss in broccoli. Water soluble, nonenzymatic antioxidant activity was similar for both cultivars. These results support the hypothesis that antioxidant protection offered by superoxide dismutase and peroxidase is important to retention of green color in broccoli.
研究了两个先前已发现黄化敏感性差异很大的西兰花品种，以确定在模拟零售展示温度下抗氧化能力与叶绿素损失之间是否存在关联。绿地品种在13摄氏度下4天内叶绿素含量保持稳定，而皇帝品种的叶绿素含量则持续下降。这些差异与水分流失的差异无关。绿地品种中的超氧化物歧化酶（SOD）和过氧化物酶（POD）活性比皇帝品种高约30%。绿地品种中超氧化物歧化酶与过氧化物酶活性的比值也较低。预计皇帝品种对氧自由基损伤和脂质过氧化的敏感性更高，因为相对于POD活性而言，过量的SOD活性可能会导致羟基自由基形成增加。皇帝品种中的过氧化氢酶（CAT）活性较高，这表明过氧化氢酶在西兰花对叶绿素损失的抗性方面并不重要。两个品种的水溶性非酶抗氧化活性相似。这些结果支持了以下假设：超氧化物歧化酶和过氧化物酶提供的抗氧化保护对西兰花保持绿色很重要。
