Huyskens-Keil S.,Humboldt University of Berlin |
Schreiner M.,Leibniz Institute of Vegetable and Ornamental Crops |
Krumbein A.,Leibniz Institute of Vegetable and Ornamental Crops |
Reichmuth Ch.,Julius Kuhn Institute |
And 2 more authors.
Acta Horticulturae | Year: 2010
In numerous epidemiological studies inverse associations between the intake of brassicaceous crops and chronic diseases, such as cancer and cardiovascular diseases, have been demonstrated. Phytochemicals such as carotenoids or phenolic compounds have been indicated to be responsible for this protective health effect. It is known that distinct changes in the content of certain phytochemicals can be triggered by the application of physical elicitors, e.g., UV and gamma irradiation, during production and postharvest operations. In order to determine the effect of short-term UV-B exposure and gamma irradiation as targeted stress treatments on the secondary plant metabolism, sprouts were subjected to three UV-B radiation intensities: 0.075, 0.10 and 0.15 Wh m -2. Gamma irradiation was performed in dosages of 0.5, 1.0, 3.0, and 6.0 kGy. The results clearly demonstrate that the plant response to short-term and moderate UV-B exposure as well as gamma irradiation is dependent on the physiological plant stage and on the phytochemical compound.
Dannehl D.,Humboldt University of Berlin |
Huyskens-Keil S.,Lentzeallee |
Eichholz I.,Lentzeallee |
Ulrichs C.,Lentzeallee |
Schmidt U.,Humboldt University of Berlin
Food Chemistry | Year: 2011
The effects of direct-electric-current (DC) on secondary plant compounds and antioxidant activity in harvested tomato fruits were investigated. A new technology was developed to supply DC to the tomatoes. Different intensities of DC (100-500 mA) with varied application times (15-60 min) were applied during postharvest. Almost all DC treatments significantly affected the secondary metabolism, resulting in an accumulation of carotenoids, phenolic compounds, and antioxidant activity in tomatoes. In the present study, optimal DC treatments were found in order to obtain the highest content of all investigated secondary plant compounds. After an adaptation time (AT) of 2 h, the maximum contents of lycopene (122.4%), ß-carotene (140.4%), total phenol (120.0%), and antioxidant activity (126.5%) were attained with a DC treatment of 500 mA for 15 min. The results changed after an adaptation time of 24 h (AT 24 h), where the highest contents of lycopene (128.7%), ß-carotene (129.6%), total phenol (113.6%), and antioxidant activity (120.9%) were obtained using the same DC treatment (500 mA), but with an application time of 30 min. Therefore, the application of DC in harvested tomato fruits may be appropriate to improve the health-promoting properties of tomatoes. © 2010 Elsevier Ltd. All rights reserved.