The increasing contamination of cereals by micromycetes and mycotoxins during malting still poses an unresolved food safety problem. This study characterises the potential of the novel, rapidly developing food production technology of Pulsed Electric Field (PEF) to reduce the viability of Fusarium fungi and the production of mycotoxins during malting. Barley, artificially inoculated with four Fusarium species, was treated by PEF with two different intensities and then malted using a standard Pilsner-type technology. Concentrations of fungi were quantified by RT-PCR, expression of fungal growth-related genes was assessed using mRNA sequencing, and mycotoxin levels were analysed by U-HPLC-HRMS/MS. Despite the different trends for micromycetes and mycotoxins after application of variously intense PEF conditions, significant reductions were generally observed. The greatest decrease was for F. sporotrichioides and F. poae, where up to six fold lower levels were achieved for malts produced from the PEF-treated barley when compared to the control. For F. culmorum and F. graminearum, up to a two-fold reduction in the PEF-generated malts was observed. These reductions mostly correlated with a decrease in relevant mycotoxins, specifically type A trichothecenes.
- MeSH
- elektřina MeSH
- Fusarium * metabolismus genetika růst a vývoj MeSH
- ječmen (rod) * mikrobiologie MeSH
- jedlá semena * mikrobiologie MeSH
- kontaminace potravin prevence a kontrola MeSH
- manipulace s potravinami metody MeSH
- mykotoxiny * biosyntéza metabolismus MeSH
- potravinářská mikrobiologie MeSH
- Publikační typ
- časopisecké články MeSH
In recent years, the interest in the health-promoting effects of hop prenylflavonoids, especially its estrogenic effects, has grown. Unfortunately, one of the most potent phytoestrogens identified so far, 8-prenylnaringenin, is only a minor component of hops, so its isolation from hop materials for the production of estrogenically active food supplements has proved to be problematic. The aim of this study was to optimize the conditions (e.g., temperature, the length of the process and the amount of the catalyst) to produce 8-prenylnaringenin-rich material by the magnesium oxide-catalyzed thermal isomerization of desmethylxanthohumol. Under these optimized conditions, the yield of 8-prenylnaringenin was 29 mg per 100 gDW of product, corresponding to a >70% increase in its content relative to the starting material. This process may be applied in the production of functional foods or food supplements rich in 8-prenylnaringenin, which may then be utilized in therapeutic agents to help alleviate the symptoms of menopausal disorders.
- MeSH
- flavanony chemie metabolismus MeSH
- flavonoidy chemie metabolismus MeSH
- fytoestrogeny chemie metabolismus MeSH
- Humulus chemie MeSH
- katalýza MeSH
- lidé MeSH
- oxid hořečnatý chemie metabolismus MeSH
- pivo analýza MeSH
- potravní doplňky analýza MeSH
- propiofenony chemie metabolismus MeSH
- rostlinné extrakty metabolismus MeSH
- rostlinné přípravky chemie metabolismus MeSH
- teplota MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Due to the increasing popularity of unfiltered beer, new methods for its preservation are needed. High-pressure processing (HPP) was applied as a final treatment of packed beer in order to assure storage stability and to retain the desired product quality. Pressures of 250 MPa and 550 MPa for 5 min were used to process unfiltered lager beers. The impact of pressure on basic analytical characteristics was evaluated, and foam stability, the content of carbonyl compounds and sensory properties were monitored during two months of storage. Most of the basic analytical parameters remained unaffected after pressure treatment, and a beneficial effect on foam stability was demonstrated. Changes in the concentration of staling aldehydes were observed during storage. Some features of the sensory profile were affected by HPP as well as by the time of storage. Our study evaluated the suitability of HPP as a novel method for shelf-life extension of unfiltered lager beer.
Beer production is one of the oldest known traditional biotechnological processes, but is nowadays facing increasing demands not only for enhanced product quality, but also for improved production economics. Targeted genetic modification of a yeast strain is one way to increase beer quality and to improve the economics of beer production. In this review we will present current knowledge on traditional approaches for improving brewing strains and for rational metabolic engineering. These research efforts will, in the near future, lead to the development of a wider range of industrial strains that should increase the diversity of commercial beers.
- MeSH
- CRISPR-Cas systémy MeSH
- fermentace MeSH
- genetické inženýrství metody MeSH
- geneticky modifikované mikroorganismy genetika fyziologie MeSH
- genom fungální MeSH
- lidé MeSH
- metabolické inženýrství metody MeSH
- pivo * MeSH
- plazmidy genetika MeSH
- regulace genové exprese u hub MeSH
- Saccharomyces cerevisiae genetika fyziologie MeSH
- veřejné mínění MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Compared to most other alcoholic beverages, the shelf life of beer is much more limited due to its instability in the bottle. That instability is most likely to appear as turbidity (haze), even sedimentation, during storage. The haze in beer is mostly caused by colloidal particles formed by interactions between proteins and polyphenols within the beer. Therefore, beers are usually stabilized by removing at least one of these components. We developed and constructed a Saccharomyces cerevisiae strain with a proline-rich QPF peptide attached to the cell wall, using the C-terminal anchoring domain of α-agglutinin. The QPF peptide served to bind polyphenols during fermentation and, thus, to decrease their concentration. Strains displaying QPF were able to bind about twice as much catechin and epicatechin as a control strain displaying only the anchoring domain. All these experiments were done with model solutions. Depending on the concentration of yeast, uptake of polyphenols was 1.7-2.5 times higher. Similarly, the uptake of proanthocyanidins was increased by about 20 %. Since the modification of yeasts with QPF did not affect their fermentation performance under laboratory conditions, the display of QPF appears to be an approach to increase the stability of beer.
Historically, hop cones (Humulus lupulus) have been used since ancient times as a remedy for many ailments and, as a source of polyphenols and bitter acids, is very effective in the treatment of metabolic syndrome (MS). Hop flavonoids, particularly xanthohumol (XN), are substances with hypoglycemic, antihyperlipidemic, and antiobesity activities. Iso-α-acids (IAA) and matured hop bitter acids (MHBA) improve health by influencing lipid metabolism, glucose tolerance, and body weight. The modulatory effect of IAA and MHBA on lipid metabolism may also be responsible for a loss in body weight. These results suggest promising applications for IAA, MHBA, and XN in humans, particularly in the prevention of diet-induced obesity and diabetes.
- MeSH
- flavonoidy chemie farmakologie terapeutické užití MeSH
- fytonutrienty chemie farmakologie terapeutické užití MeSH
- glukózový toleranční test MeSH
- Humulus chemie MeSH
- lidé MeSH
- metabolický syndrom farmakoterapie prevence a kontrola MeSH
- metabolismus lipidů účinky léků MeSH
- molekulární struktura MeSH
- propiofenony farmakologie terapeutické užití MeSH
- tělesná hmotnost účinky léků MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
In recent years, an interest in the health-promoting activities of derivatives of hop constituents has grown. Pharmaceutically important substances in hop are primarily prenylated flavonoids, in the context with their proven biological effects. A reliable analytical method using HPLC-PDA for determination of all prenylated flavonoids (xanthohumol, isoxanthohumol, 8-prenylnaringenin) in hop materials was developed.
- MeSH
- antioxidancia MeSH
- antitumorózní látky fytogenní MeSH
- chemické techniky analytické metody přístrojové vybavení trendy využití MeSH
- flavonoidy * analýza MeSH
- Humulus chemie MeSH
- potravinářský průmysl MeSH
- vysokoúčinná kapalinová chromatografie * metody přístrojové vybavení využití MeSH
- Publikační typ
- práce podpořená grantem MeSH
Female hop cones are used extensively in the brewing industry, but there is now increasing interest in possible uses of hops for non-brewing purposes, especially in the pharmaceutical industry. Among pharmaceutically important compounds from hops are flavonoids, having proven anticarcinogenic, antioxidant, antimicrobial, anti-inflammatory and estrogenic effects. In this review we aim to present current knowledge on the biotransformation of flavonoids from hop cones with respect to products, catalysis and conversion. A list of microbial enzymatic reactions associated with gastrointestinal microbiota is presented. A comparative analysis of the biological activities of hop flavonoids and their biotransformation products is described, indicating where further research has potential for applications in the pharmaceutical industry.
