The occurrence and content of some polyphenols and the antioxidant activity of compounds present in grape berries, stems and leaves of <i>Vitis vinifera</i> L. were evaluated. Three white and three blue varieties of grapevine were investigated. The contents were determined of <i>trans</i>-resveratrol, <i>trans</i>-piceid, caftaric acid, tryptophan, catechin, epicatechin, total polyphenols, and flavanols, both in healthy material and in the samples of the plant material infested with microorganisms (<i>Botryotinia fuckeliana</i> Whetzel anamorph <i>Botrytis cinerea</i> Pers.; Uncinula necator (Schw.) Burr; <i>Plasmopara viticola</i> (Berk. & M.A. Curtis) Berl & De Toni). The antioxidant activity of the extracts obtained was determined by different methods: FRAP (Ferric Reducing Antioxidant Power), DPPH (2,2-diphenyl-1-picrylhydrazyl radical) and TAC-PCL (Total Antioxidant Capacity of Photochemiluminescence). The content of <i>trans</i>-resveratrol varied between 0.3–2.3 mg/kg and 0.7–12.1 mg/kg in non-infested and infested grape berries, respectively. The content of <i>trans</i>-piceid between 0.6–2.9 mg/kg and 1.5–6.3 mg/kg in non-infested and infested grape berries, respectively. The content of trans-resveratrol varied between 2.5–10.3 mg/kg and 3.7–20.9 mg/kg in healthy and in infected leaves, respectively. The content <i>trans</i>-piceid varied between 11.3–58.4 mg/kg and 18.5–60.9 mg/kg in the healthy and in the infected leaves, respectively. The highest content of trans-resveratrol was found in stems (16.3–276.3 mg/kg). In young lateral shoots, the highest levels of <i>trans</i>-piceid (12.6–99.7 mg/kg) and caftaric acid (474–2257 mg/kg) were determined. The infested grape berries showed a higher antioxidant activity, which was most closely correlated with the content of total polyphenols (correlation coefficient = 0.8336–0.9952).

Abstract:The effects of the pressing technology and clarification of white grape musts on concentrations of phenolic compounds and their antioxidative capacity were investigated. Four different varieties were processed by hydraulic or pneumatic pressing technologies. In the individual stages of pressing and after the application of different doses of the clarification agent, must samples were analysed for the content of polyphenols and the antioxidative capacity. The highest concentrations of caftaric acid were estimated in the musts made by hydraulic pressing from grapes of Welschriesling variety. On the other hand, musts made from grapes of Grüner Veltliner showed the highest contents of trans-piceid in both variants of pressing. The values of antioxidative capacity of the must samples analysed were not significantly different. The influence of clarification on the changes of phenolic substances in young red wines of Saint Laurent variety was also studied. Six various clarifiers were tested as applied in two different doses. Polyvinylpolypyrrolidone caused the highest losses of trans-resveratrol in the course of red wine clarification. The concentrations of catechin, epicatechin, and total anthocyanins as well as the colour parameters of red wines were influenced at most by the application of egg white.

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Broccoli sprouts contain 10–100 times higher levels of sulforaphane than mature plants, something that has been well known since 1997. Sulforaphane has a whole range of unique biological properties, and it is especially an inducer of phase 2 detoxication enzymes. Therefore, its use has been intensively studied in the field of health and nutrition. The formation of sulforaphane is controlled by the epithiospecifier protein, a myrosinase co-factor, which is temperature-specific. This paper studies the influence of temperature, heating time, the addition of myrosinase in the form of Raphanus sativus sprouts in constant ratio to broccoli sprouts, and other technological steps on the final sulforaphane content in broccoli sprout homogenates. These technological steps are very important for preserving sulforaphane in broccoli sprouts, but there are some limitations concerning the amount of sulforaphane. We focused, therefore, on the extraction process, using suitable β-cyclodextrin, hexane and ethanol, with the goal of increasing the amount of sulforaphane in the final extract, thus stabilizing it and reducing the required amount sulforaphane needed, e.g., as a dietary supplement.

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The chemical composition of organic compounds in the extractable organic matter of propolis collected from the Baha region of Saudi Arabia was investigated. The propolis samples were extracted with methanol followed by column chromatography and collected in fractions (15 ml), then analysed by gas chromatography-mass spectrometry (GC-MS). Samples were injected with and without derivatization using BSTFA simultaneously. The results showed that a total of 61 chemical compounds were characterized and identified by analysing each of the fractions. Out of these, 33 compounds have not been reported previously. The Baha sample contains a high amount of aromatic acids, alcohol and phenol aldehydes. In addition to these, some other compounds (aliphatic acids, sugar derivatives, steroid derivatives and flavone derivatives) were also present. Some of the identified compounds have shown diverse biological activities: antimicrobial, anti-inflammatory, and analgesic activities. Methanolic extraction of propolis followed by column chromatography and GC-MS resulted in the separation of a high number of compounds compared with propolis samples from different geographical regions. The new identified compounds were found related to the flora of the Baha region. Therefore, the composition of propolis differs according to the plants found in the area in which it is produced. This may be used in the determination of a geographical area as the source of a propolis sample.

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