Green solvents being the only alternative due to legislative and environmental requirements, new methods are developed using environmentally friendly chemicals not compared to efficient but toxic classical solvents. The aim of this study was to vindicate the use of green solvents from the viewpoint of extraction yield and costs (including recycling or waste disposal) for the extraction of quercetin, its derivatives and protocatechuic acid from onion peel. Pressurized liquid extraction efficiency was compared for methanol, ethanol, ethyl acetate, acetone and their combinations, pure and modified with citric or acetic acid, at 40-120 degrees C contra aqueous ethanol, also modified with citric or acetic acid under the same conditions. Methanol and ethanol were the most promising classical and green solvents; method was optimised separately for each analyte: quercetin, quercetin glucoside, quercetin diglucoside and protocatechuic acid. While the best conditions slightly differ, ethanol/water (70/30 v/v) with 0.1 % of acetic acid is recommended at sample to inert material ratio 1:2 (v/v), 15 MPa, 120 degrees C and three cycles of 15 min extraction time for all analytes except quercetin diglucoside, which is extracted better by toxic but efficient methanol/water (70/30 v/v) with 0.1 % of acetic acid, also at 120 degrees C, 15 MPa and 3 x 15 min. In general, environmentally friendly solvent is more favourable both for the main analyte, quercetin (20,503 mg/kg), for protocatechuic acid, which has the highest antioxidation activity (935 mg/kg), and for total sum of analytes, "quercetin complex" (28,966 mg/kg). For determination of quercetin diglucoside, separate extraction by methanol is recommended (958 mg/kg).
Essential oils (EOs) obtained from spices, herbs and medicinal plants are well known in traditional medicine and are an area of interest due to their various biological activities. On the other hand, spices are consumed on a daily basis and have the potential to be contaminated with mycotoxins. Therefore, it is crucial to consider them as a factor in health safety. The present study investigated the yield, EOs composition and mycotoxins (T-2 toxin and HT-2 toxin) content in five spices (caraway, anise, coriander, fennel, dill) of the Apiaceae family. EOs obtained by hydrodistillation were analysed and identified by gas chromatography coupled to mass spectrometry (GC-MS). Mycotoxins were determined using liquid chromatography coupled to a mass spectrometer (LC-MS). The yields of EOs ranged between 0.66% and 5.26% depending on the type of spice. The results showed that the major components present in caraway samples were carvone (53.02%-59.65%) and limonene (39.34%-46.08%); in anise trans-anethole (93.79%-95.70%); in coriander linalool (62.02%-67.91%); in fennel trans-anethole (0.82%-92.87%) or estragole (2.53%-89.51%); and in dill samples limonene and carvone (about 47.00% each), or dill apiole (42.08%) and limonene (29.80%). T-2 and HT-2 toxins were detected in small amounts (0.37-2.69 mu g/kg) in three of 24 analysed samples.
Phytic acid is the main storage of phosphate in grains of staple crops. As phytic acid is hardly digestible for non-ruminants microbial phytases are used to supplement animal feed to enhance phosphate digestibility. A fungal phytase gene was introduced into barley with the aim of enhancing phosphate digestibility. Transgenic homozygous barley over-expressing fungal phytase phyA showed a 3.3fold increase in mature grain phytase activity. Field trials at two locations in the Czech Republic were conducted in a five-year experiment to test transgene stability and activity under field conditions. Increased phytase activity gradually decreased over the generations showing the most significant drop in the initial years of field trials. Molecular analysis revealed methylation in the coding sequence of the phyA transgene, suggesting transcription gene silencing. On the other hand, herbicide resistance used for selection of transgenic plants was functional over all generations. The feasibility of crossing the transgene into the feeding cultivar Azit was demonstrated with subsequent stabilization of hybrid progeny through androgenesis. Our results indicate that the Azit genetic background tended to reduce phytase activity in mature grains of hybrids. Grain-specific over-expression of fungal phytase driven by an amylase promoter improved phosphate levels during germination. Unfortunately, a malting experiment revealed that phytase over-expression did not significantly improve malting parameters. In fact, the higher nitrogen content in unmalted grain negatively affected the quality of the malt produced from them.
After the 2024 harvest, the following varieties of spring malting barley were registered in the Czech Republic: LG Vaclav, Matika, Starship, and SY Signet, along with the varieties of winter non-malting barley: Organa, KWS Antonis, and RGT Alessia. The LG Vaclav variety exhibited low levels of proteolytic and cytolytic modification and a low level of apparent final attenuation, thus meeting the conditions required for varieties recommended for the production of beer with the protected geographical indication 'České pivo'. The spring barley varieties Matika, Starship, and SY Signet demonstrated very good malting quality. They provided malt with a rich extract content. Proteolytic modification was optimal to higher for these varieties. The degradation of cell walls was at an optimal level for the mentioned varieties. The β-glucan content of malt wort was at a satisfactory to optimal level. The wort of these varieties was mostly clear.
The pest Drosophila suzukii also causes significant damage to grapevine berries. Kaolin-based products and biostimulants were tested in an experiment to reduce the development of Drosophila suzukii and the development of sour rot, while the effect on grape quality parameters was also investigated. Surround, building kaolin, NovaFerm Orion, NovaFerm Sirius and Hycolat were tested on Riesling, Traminer and Palava varieties between 2023 and 2024. In terms of reducing damage to Drosophila suzukii berries, the most effective application was Surround (3%, 5%). Of the biostimulants, NovaFerm Orion and Hycolat were the most effective. The same products also showed good efficacy in point of reducing the development of sour rot. In view of the effect on grape quality parameters, the most significant negative impact was on pH values. Rheinriesling and Traminer showed an increase in pH values compared to the untreated control. pH is a very important parameter in the context of grape processing and fermentation.
