Anna Mareczek

Antioxidant ability of broccoli flower buds during short-term storage

Some metabolic changes in broccoli heads stored under commonly-applied conditions were investigated. Freshly harvested broccoli of Lord cultivar were stored at 20°C and at 5°C for 3 and 7 days, respectively, either non-packaged or packaged in polymeric film samples. Short-term storage at room temperature induced accumulation of total phenols, especially in non-packaged broccoli. With low-temperature treatment, phenol content rose only after 7 day storage of non-packaged heads. Both low temperature and application of polymeric foil stopped losses of ascorbic acid. Total antioxidant activity increased considerably during storage in all treatments. Changes of fatty acids were manifested as a slight decrease in saturated fatty acids in cold storage and increase of polyunsaturated fatty acids in most treatments. Metabolism of fatty acids did not correspond to thiobarbituric acid-reactive substances (products of lipid peroxidation).

Phenolic metabolism in root slices of selected carrot cultivars

Carrot root slices, stored for 4 days at 20 °C reacted with a strong accumulation of total phenols, especially chlorogenic acid. A significant accumulation of isocoumarin content within the peel was observed in stored slices. Synthesis of phenols was accompanied by an increase in phenylalanine ammonia lyase activity, wound induced respiration and ethylene production.The great variability among the studied four cultivars was found concerning isocoumarin synthesis, PAL activity, respiration rate and ethylene evolution, but less distinct in the case of chlorogenic acid accumulation.The carrot slices obtained from freshly harvested roots were more sensitive to mechanical damage and short-term storage than those prepared from roots previously stored.

Some antioxidant and senescence parameters of broccoli as related to its developmental stages

In broccoli heads grown in spring and in autumn, and harvested at four various developmental stages antioxidant ability as well as certain indices of plant senescence were investigated. Development of broccoli heads was accompanied by losses of chlorophyll and ascorbic acid. At pre-florescence stage accumulation of soluble phenolics was observed. Activity of peroxidase in the initial stage of growth increased significantly and its high level was mantained during the whole growing period. The profound evolution of ethylene was manifested by plants of the pre-florescence stage.In broccoli grown in spring the higher contents of chlorophyll and phenolics in comparison with the autumn experiment were observed, as well as slightly higher activities of peroxidase and catalase. Total antioxidant activity was considerably higher in spring than in autumn.