2025-08-15
Karolína Špačková, Olga Cwiková, Tomáš Gregor, Luděk Hřivna, Naděžda Vaňková
The study investigated the contamination of malting barley grain with mycotoxins of Fusarium during the process of growth and development of grain and its subsequent processing in the malting plant into manufactured beer. Attention was focused on their hygienic quality, zearalenone and deoxynivalenol content was determined by HPLC. None of the samples exceeded the legal limits. The experiment evaluated the influence of cultivar (Francin, Bojos), the effect of nitrogen fertilization rate and fungicide treatment. Francin appeared more resistant to ZEA occurrency, while Bojos was more resistant to DON occurency. Nitrogen fertilization rates of 80 and 110 kg/ha may have caused a higher susceptibility of the crop to Fusarium attack. The hypothesis that mycotoxin susceptibility would increase with increasing fertilization rate was not supported. The environment of the malt house may also have contributed to the increase in mycotoxin content. In the case of fungicide application, it cannot be clearly assessed whether it affected the mycotoxin content. The field experiment was adversely affected by bad weather. Differences (P < 0.05) were found when monitoring the ZEA and DON content of Bojos and Francin grain samples. The ZEA content of Bojos and Francin malt were not different (P > 0.05). Significant differences (P < 0.05) were found when monitoring the DON content of Bojos malt samples, the DON content of the Francin malt was comparable (P > 0.05). The Bojos beer samples were not different in ZEA and DON content (P > 0.05). For Francin beer, there were differences (P < 0.05).
2025-04-15
Yunqian Cui, Lei Zhu, Xiaocong Wu, Xiangyu Xi
The brewing technology of kelp beer with kelp powder and its anticoagulant effect were explored in this study by pre-trials and laboratory-scale tests, the adding method and dosage of kelp powder were determined by analysis of anticoagulant effect and sensory evaluation of beers. Then, a 100 L pilot-scale brewing was successfully accomplished, and the physicochemical indexes and flavor components of final kelp beers were determined, the anticoagulant effect of kelp beer was assessed by measuring the values of activated partial thromboplatin time (APTT, 123.16±1.96 s), prothrombin time (PT, 32.80±0.26 s), and thrombin time (TT, 14.22± 0.51 s), which were higher than those of control beer. Finally, by the analysis of infrared spectroscopy, it was the polysaccharides and fucoidans originated from kelp powder in brewing that imparted the anticoagulant effect of kelp beer.
2025-02-15
Vratislav Psota, Jørund Geving, Milan Starec, Markéta Garčárová, Petr Holub, Jaromír Fiala, Sigurd Johan Saure
This case study examines the impact of production methods and barley varieties on the quality of farm malts. The experiment used samples of three spring barley varieties: the two-row varieties Domen and Thermus, and the six-row variety Bredo. Four samples of farm malts were produced from these varieties using different production methods, which are described in tabular form. The differences in quality between the samples were significant. The sample labelled Thermus JG produced malt that approached current quality standards. The other three samples showed low levels of modification. The extract content in the malt dry matter ranged from 72.7% to 79.5%, the Kolbach index ranged from 32.6% to 33.7%, and the ß-glucan content ranged from 1010 to 1290 mg/l. The farm malt samples produced cloudy wort, and the mash aroma was described as burnt, smoky, and smokey. The laboratory malt produced in the micro-malting plant also had significantly low quality. The results indicate that the choice of variety and production method has a crucial impact on the quality of the final malt.
2024-12-16
Janette Bobalova, Dana Strouhalova
As protein composition and modification are critical for malt and beer quality, proteomic approaches have the potential to improve malting and brewing processes, as well as to monitor and characterize important low molecular weight proteins related to food allergy. New product compositions and industrial processes create additional needs that require much greater technological development. The detection and quantification of allergenic proteins by mass spectrometry is promising and contributes to greater accuracy, thereby significantly improving consumer information. In the case of allergenic proteins, a wide range of isoforms, post-translational modifications and other structural changes during the technological process can increase or decrease their allergenicity. In this context, we focused on tracking barley proteins related to pathogens, a large proportion of which are allergy-related. These mainly include a group of protease/amylase inhibitors such as α-amylase/trypsin inhibitor CMa, CMb, CMe, α-amylase inhibitor BDAI-1. Similarly, a lipid transfer protein 1 has been identified as a major beer allergen.
2024-12-16
Roman Králik, Petr Gabriel, Martin Dušek, Jaromír Antoch
The impact of light on beer degradation is a well-established phenomenon, leading to development of undesirable flavours or, in severe cases, complete spoilage. This study investigates the extent to which photodegradation is perceptible to beer consumers. Beer samples in commercial bottles were subjected to controlled light exposure to induce defined levels of degradation. The degree of light damage was monitored using both an optical method of tracking changes in absorbance and riboflavin content via HPLC and a sensory evaluation by a lay consumer sensory panel. The findings from the sensory panel were statistically compared with the optical measurement results, highlighting correlations between the sensory perception and quantifiable optical changes.
2024-10-15
Nikol Šimečková, Tomáš Gregor, Luděk Hřivna, Veronika Kouřilová, Renáta Dufková, Jana Simonová, Iva Burešová
The effect on added pseudocereals (quinoa, amaranth, and buckwheat) on characteristics of beer was studied on beer samples prepared from barley malt, pseudocereals, water, hops, and brewer's yeast. Pseudocereals were used as a partial malt substitute (0%, 10%, 20%, 30%). The colour of laboratory prepared beers was measured using a Konica Minolta CM 3500d. Basic parameters of beers (alcohol content, real extract and original extract of the wort) were measured using a FermentoFlash. The amount of fructose, glucose, maltose and maltotriose in the wort and in the beers was determined using an Agilent Technologies HPLC. A sensory evaluation was also performed. The results of the different variants did not vary in terms of alcohol content. Beer lightness did not differ much between the pseudocereals variants. However, control beer was darker than beers with added pseudocereals. Generally, the beers with pseudocereals did not differ much from the control beer without pseudocereals.
2024-06-17
Vratislav Psota, Olga Dvořáčková, Markéta Garčárová, Rastislav Boško
After the 2023 harvest, four varieties of spring barley were registered in the Czech Republic. The malting quality was determined in three varieties. After four years of testing, LG Tuplak was registered. After three years of testing, the spring barley varieties LG Lokal, Sting, and the non-malting variety Ranee were registered. LG Tuplak and LG Lokal showed low activity of proteolytic and cytolytic enzymes and a low level of apparent final attenuation and thus fulfilled the conditions for varieties recommended for the production of beer with the protected geographical indication 'České pivo'. The spring barley variety Sting showed very good malting quality. It provided a sweet wort with a rich extract content in malt dry matter (above 83%). Proteolytic modification was optimal to higher in this variety. Cell wall degradation was at an optimal level in the Sting variety. The varieties tested gave clear to opalescent sweet wort.
2024-04-16
Karel Fous, Anna Jarolímová, Petra Kubizniaková, Katarína Majtán
Beer stability, influenced by physical, chemical, and biological factors, poses a considerable challenge for breweries. Biological stability, as a major concern, is effectively managed through practices such as good hygiene, pasteurization, and filtration. Microbiological contamination, often recognizable by increased turbidity or off-flavours, is influenced by temperature, with optimal conditions promoting the growth of specific microorganisms. Lower temperatures slow down flavour changes and chemical reactions in beer, impacting its non-biological stability. This case study explores the impact of storage temperature on autolysis off-flavour development in 10 different unfiltered and unpasteurized beers. The results showed that autolysis off-flavour occurred at both low and higher storage temperatures and that its dependence on the temperature was minimal. This unexpected fact was discovered mainly due to uncovered significant contamination of the commercial beers tested (wild yeasts, lactic acid bacteria, enterococci and coliform bacteria). For this reason, the concentration of cells in the beer appeared as a more influential factor in the development of off-flavours, including autolysis, than the storage temperature. The partial results need to be studied in more detail, nevertheless, we felt it was important to publish the revelation of a strong contamination of beers purchased from regular stores for our experiments. At this point it can already be concluded that the low storage temperature did not help to prevent the development of the contamination and the associated sensory deterioration of the beers.