Characterisation of Some Phytochemicals Extracted from Black Elder (Sambucus nigra L.) Flowers Subjected to Ozone Treatment

Elderflowers are a well-known source of bioactive compounds. The amount of isolated bioactive compounds may be increased by applying various abiotic and biotic factors. Gaseous ozone (10 and 100 ppm) was used in the process of preparing flowers. Next, the flowers were treated with sugar syrup to extract bioactive compounds. It was shown that this treatment, including the influence of extraction temperature, significantly affects the contents of polyphenols (liquid chromatography-mass spectrometry (LC-MS) methods) and vitamin C, as well as the antioxidant potential (cupric reducing antioxidant capacity (CUPRAC method)), the profile of volatile substances (head space-solid-phase microextraction (HS-SPME methods)) and the colour of the syrup (Commission Internationale de l'Eclairage (CIE) L*a*b* methods). The findings show that an increased dose of ozone and higher extraction temperature applied in the process of syrup production resulted in higher contents and different compositions of bioactive compounds. The highest contents of bioactive compounds were identified in syrup obtained from raw material treated with ozone for 15 min (concentration = 10 ppm) and extraction with sugar syrup at a temperature of 60 °C.

The morphological and antioxidant characteristics of inflorescences within wild-growing genotypes of elderberry (Sambucus nigra L.)

The aim of this study was to determine the basic morphological characteristics (weight, length) and antioxidant activity (using DPPH method) of elderberry (Sambucus nigra L.) inflorescences as well as some elderberry-derived food products prepared from fresh (honey, alcoholic extract, tea infusions) and dried inflorescences (syrup). For the study of problematic, it was used 113 wild-growing genotypes of elderberry from 56 locations in Slovakia growing at an altitude of 98.15 - 712.32 m. The weight of fresh inflorescences ranged from 0.45 to 57.59 g (75.65% coefficient of variation value), the total length of inflorescences ranged from 19.0 to 282.0 mm (22.42%), the length of inflorescence´s stems from 9.0 to 197.0 mm (31.51%), a number of petals predominated pentanumerous petals. Variability in primary and secondary branching reported a low to high degree of variability among as well as within the genotypes. Results showed significant differences in the shape of inflorescences and the colour of flowers among each genotype. Antioxidant activity by DPPH method in elderberry inflorescence water extract was between 85.12 and 89.29%. Activation of tea infusions and beverages was ensured using a mechanism Kalyxx based on galvanic effect. In beverages made from 10% diluted honey prepared from fresh inflorescences in the carbohydrate-based extract, anti-radical activity was determined in the range of 16.81 - 24.16%. In an alcoholic extract from fresh inflorescences, anti-radical activity was between 90.99 and 93.16%. In beverages acquired from the syrup of flowers, we identified antioxidant activity ranging from 37.92 (10%) to 62.82% (40%). Results indicated that elderberry inflorescences and elderberry-derived food products can be attractive to consumers and in future can increase the assortments of healthy products.

Antioxidant activity of tokaj essence

The aim of the presented experiment was to measure the content of total polyphenols and antioxidant potential of Tokaj essence from the years 1999, 2006, 2007, 2009, 2013, 2015. Tokaj essence is produced by fermentation of concentrated must from botrytised grape berries. The highest content of polyphenols was determined in the essence of 1999 (275.8 ±18.17 mg.L-1) and the lowest in the sample of 2015 (118.8 ±12.28 mg.L-1). Antioxidant activity was determined by two methods DPPH and PRAC (permanganate reducing antioxidant capacity). Antioxidant DPPH method showed that the essence of year 1999 had significantly the highest activity (63.4 ±0.81 µmol.L-1 Trolox) while essence of year 2015 (47.5 ±1.58 µmol.L-1 Trolox) featured the lowest activity. The results of method PRAC, which determine the total reducing capacity of the essence, do not correlate with the results of DPPH and total phenolic content, because of higher content of saccharides, which gave false positive test results. The method PRAC is not suitable for measuring antioxidant activity of tokaj esence. The results showed that aging of wine increased the content of polyphenols and also its antioxidant activity. High content of polyphenols and the great antioxidant activity of Tokaj wine receive their beneficial effect to human health.