Effects of Various Doses of Selenite on Stinging Nettle (Urtica dioica L.)

The aim of this study was to investigate the effects of selenium (Se) on the growth, accumulation and possible mechanisms of Se transport in certain parts (roots, leaves, stamp and apex) of nettle (Urtica dioica L.) plants. Se was supplemented by one-shot and two repeated doses to the soil (2.0 and 4.0 mg Se per kg of substrate). Selenium content in roots increased linearly with dose and was significantly higher compared to other plant parts of interest. However, growth of the above-ground parts of plant as well as roots was slightly inhibited with increasing selenium concentration in comparison to the untreated plants. The content of phytochelatin2, a low molecular mass peptide containing a sulfhydryl group, correlated well with the Se content. This suggests a possible stimulation of synthesis of this plant peptide by Se

Quality of carrots as affected by pre- and postharvest factors and processing

The aim of this review is to provide an update on factors contributing to quality of carrots, with special focus on the role of pre- and postharvest factors and processing. The genetic factor shows the highest impact on quality variables in carrots, causing a 7–11-fold difference between varieties in content of terpenes, β-carotene, magnesium, iron and phenolics as well as a 1–4-fold difference in falcarindiol, bitter taste and sweet taste. Climate-related factors may cause a difference of up to 20-fold for terpenes, 82% for total sugars and 30–40% for β-carotene, sweet taste and bitter taste. Organic farming in comparison with conventional farming has shown 70% higher levels for magnesium and 10% for iron. Low nitrogen fertilisation level may cause up to 100% increase in terpene content, minor increase in dry matter (+4 to +6%) and magnesium (+8%) and reduction in β-carotene content (−8 to −11%). Retail storage at room temperature causes the highest reduction in β-carotene (−70%) and ascorbic acid (−70%). Heat processing by boiling reduces shear force (−300 to −1000%) and crispiness (−67%) as well as content of phenolics (−150%), terpenes (−85%) and total carotenes (−20%) and increases the risk of furan accumulation. Sensory and chemical quality parameters of carrots are determined mainly by genetic and climate-related factors and to a minor extent by cultivation method. Retail temperature and storage atmosphere as well as heating procedure in processing have the highest impact in quality reduction. © 2013 Society of Chemical Industr