The effect of selenium biofortification on phytomass yield, selenium, essential oil and phenolic compounds content as well as antioxidant properties of basil leaves was investigated. Selenium in form of sodium selenate was applied either in nutrient solution or by foliar spraying at three levels (2.0, 5.0 and 10.0 μM). Selenium treatment significantly increased Se concentration in leaves up to 20.23 μg g⁻¹ (addition in nutrient solution) and 10.74 μg g⁻¹ (foliar application). Neither a toxic nor a beneficial effect of Se addition on the plants was observed. Se application of 2 µM Se in nutrient solution and of 5 µM Se by foliar spraying successfully enhanced production of essential oils, hydroxycinnamic acids, total phenolics and antioxidant activity of basil leaves. The anthocyanin content was positively affected only by application of Se in nutrient solution. Considering both an increase in the Se concentration in basil leaves and an increase in the production of phytonutrients, the optimal doses of selenium can be considered to be 5 and 10 μM for Se addition in nutrient solution and by foliar treatment, respectively. The results confirm the possibility of the enrichment of basil plants with selenium and thereby improving the nutritional qualities of the human diet.

The factors affecting the efficiency of micelle-mediated extraction of phenolic compounds from apple pomace was investigated. Higher extraction efficiency by using as a solvent an aqueous solution of Tween 80 in comparison to Triton X-100, Span 20, Tween 20, 70% ethanol, and water was shown. Four independent variables (Tween 80 concentration, time, solvent-to material ratio, and pH) to enhance the recovery of polyphenols from apple pomace was investigated. Applying response surface methodology, the second order polynomial regression equation showing dependence of the yield of polyphenols on the extraction parameters was derived. The adjusted regression coefficient (R² = 98.73%) and the lack-of-fit test (p > 0.05) showed a good accuracy of the developed model. The difference between observed and predicted values was no more than 3%. The optimal extraction conditions were found to be Tween 80 concentration of 1.14%, time of 65 min, solvent-to-material ratio of 104 mL g⁻¹, pH of 3.8. Under optimal conditions the predicted total phenolic compounds content was 7.75 mg g⁻¹. The obtained apple pomace extracts were characterized in terms of their antioxidant activity. The proposed extraction technology by using Tween 80 aqueous solution as a solvent allows obtaining the extracts with high content of polyphenols which are suitable for the applications in food, cosmetic, and pharmaceutical products requiring a surfactant to stabilize them.

Rye (Secale cereale L.) is one of the most important cereal crops in Eastern and Northern Europe, showing better tolerance to environmental stress factors compared to wheat and triticale. Plant response to the crude oil-polluted soil depends on plant species, oil concentration, time of exposure, etc. The current study is aimed at investigating the growth, oxidative stress and the response of antioxidative system of two rye varieties (Krona and Valdai) cultivated on crude oil-contaminated soils at different concentrations (1.5, 3.0, 6.0, and 12.0%). Inhibition of rye growth was observed at crude oil concentrations of above 3% for above-ground plant parts and of above 1.5% for roots. A decrease in content of chlorophyll a and total chlorophylls in Krona variety was detected at 1.5% oil concentration in soil and in Valdai variety at 3% oil concentration. Compared with the control, the content of malondialdehyde was significantly increased in the Krona variety at 3% oil concentration and in Valdai variety at 6% oil concentration. The crude oil-induced oxidative stress was minimized in rye plants by the enhanced contents of low-molecular antioxidants (proline, non-protein thiols, ascorbic acid, phenolic compounds) and activities of superoxide dismutase, catalase, ascorbate peroxidase, and glutathione peroxidase. The strongest positive correlation was detected between the content of malondialdehyde and contents of proline (r = 0.89–0.95, p ≤ 0.05) and phenolic compounds (r = 0.90–0.94, p ≤ 0.05) as well as superoxide dismutase activity (r = 0.81–0.90, p ≤ 0.05). Based on the results of a comprehensive analysis of growth and biochemical parameters and of the cluster analysis, Valdai variety proved to be more resistant to oil pollution. Due to this, Valdai variety is considered to be a promising rye variety for cultivation on moderately oil-polluted soils in order to decontaminate them. At the same time, it is necessary to conduct further studies aimed at investigating oil transformation processes in the soil-rye system, which would make it possible to determine the efficiency of using this cereal for soil remediation.