Pavel Híc

This study focuses on analyzing the impact of various fining agents on apple cider and evaluating their effects on its physical–chemical and sensory properties. Despite its common cloudy state, some consumers prefer clear apple cider. Within this study, two variations of apple cider were analyzed: original cider and cider with added barrique extract. Eight different fining agents were applied to these samples, specifically bentonite, gelatin, polyvinylpolypyrrolidone, egg white protein, activated carbon, pea protein, isinglass, and silica gel. The results revealed that the use of fining agents significantly impacted the antioxidant content in apple cider. The most substantial reduction in antioxidants was observed in samples with added activated carbon, resulting in a 75% decrease to values of 0.11–0.26 mmol TE/L. This decrease in antioxidants correlated with a decline in total polyphenols. Sensory analysis demonstrated statistically significant differences among the various apple cider samples. Bentonite and egg white protein had minimal adverse effects on sensory properties, while activated carbon had the most pronounced negative impact on the aroma and taste of the cider. This study provides valuable insights into the use of fining agents in winemaking technology and their effects on the quality of apple cider, considering consumer preferences.

This study evaluated the physiochemical changes of one commercial European pear variety ‘Conference’ and one Asian pear variety ‘Yali’ during 60 days of storage at 1 °C. Content of organic acids, ethylene and formation of CO₂ were determined using HPLC/UV-VIS and GC/FID and TCD detectors, respectively. This study presents an evaluation of the influence of the above-mentioned factors and long-term storage on quality parameters, including the antioxidant capacity of an important European and Asian pear cultivar. There was a significant effect of temperature on respiration rate in both varieties. Development of the respiration intensity had a similar course in European and Asian pears. The high values of CO₂ production at the beginning of storage for the variety ‘Conference’ (14.08 mg·kg⁻¹·h⁻¹) and ‘Yali’ (23.37 mg·kg⁻¹·h⁻¹) were followed by a sharp decline of 80% and 83% at later stages of storage at 1 °C, respectively. Ethylene formation in fruit increased with storage time and was the highest after 60 days in cold storage, especially in ‘Yali’ (7.14 µL·kg⁻¹·h⁻¹). The results show the relation between ethylene formation and ripening-related fruit parameters. The ‘Yali’ variety showed negligible changes in soluble solids content and flesh firmness during storage ranging from 0.35 to 0.60 MPa. The most represented sugar determined enzymatically was fructose and malic acid was the dominant organic acid in pear fruit. Antioxidant activity determined using the FRAP and DPPH methods did not change significantly during 60 days of storage.

Grapevine trunk diseases (GTDs) pose a major threat to the wine industry worldwide. Currently, efficient biological methods or chemical compounds are not available for the treatment of infected grapevines. In the present study, we used an extract from the knotwood of spruce trees as a biological control against GTDs. Our in vitro trial was focused on the antifungal effects of the extract against the most common GTD pathogens—Cadophora luteo-olivacea, Dactylonectria torresensis, Diaporthe ampelina, Diaporthe bohemiae, Diplodia seriata, Eutypa lata, and Phaeoacremonium minimum. Our in vitro trial revealed a high antifungal effect of the extract against all tested fungi. The inhibition rates varied among the different species from 30% to 100% using 1 mg·mL⁻¹ extract. Subsequently, the efficiency of the extract was supported by an in planta experiment. Commercial grafts of Vitis vinifera were treated with the extract and planted. The total genomic DNA of grapevines was extracted 10 days and 180 days after the treatment. The fungal microbial diversities of the treated/untreated plants were compared using high-throughput amplicon sequencing (HTAS). Treated plants showed 76.9% lower relative abundance of the genus Diaporthe and 70% lower relative abundance of the genus Phaeoacremonium 10 days after treatment. A similar scenario was observed for the genus Cadophora 180 days after treatment, where treated plants showed 76% lower relative abundance of this genus compared with untreated grapevines.

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.

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, the scientific journal of the Mendel University in Brno, Czech Republic

Cherries are a traditional commodity grown in the Czech Republic. Placing into a cold room is essential for the fruit to be preserved in the long term. Even if optimum storage conditions are followed, the shelf life is relatively short. This study observed the effect of packing cherries into the Xtend polymer wrap on slowing down the degradation of the fruit during the storage period. The experiment was conducted using 4 varieties of the sweet cherry (Prunus avium L.) from the identical site (Stošíkovice, Czech Republic) - 'Vanda', 'Kordia', 'Sweetheart' and 'Regina'. Part of the fruit was stored at 20 °C for 7 days (conditions in retail chains) and other part of the fruit was stored at 1 °C for 50 days, first half of fruit was stored in Xtend polymer wrap and second half in the normal air conditions. Changes were also investigated in fruit quality parameters (soluble solids, titratable acidity, weight loss, peel firmness and respiration intensity) under the shelf life conditions when the fruit was placed at the distribution temperature of 20 °C after removal from the store and analysed after 5 and 10 days. Packed fruit exhibited significantly lower weight loss than unpacked fruit. Unpacked fruits showed visible signs of wilting and it is connected to the water loss and loss of turgidity of fruit. Soluble solids content and titratable acidity reduced generally less in unpacked fruit, which was probably related to the higher weight loss in this variant. Between the packaged and control fruit firmness was not statistically significant. Carbon dioxide production characteristic the intensity of respiration was typically higher at 1 °C for fruit packed in the Xtend film. This fruit, however, largely responded by reducing the intensity of respiration when removed from the store and placed at 20 °C, whereas in unpacked fruit there was a several-fold increase in carbon dioxide production under such conditions.

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, the scientific journal of the Mendel University in Brno, Czech Republic

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, the scientific journal of the Mendel University in Brno, Czech Republic

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, the scientific journal of the Mendel University in Brno, Czech Republic