Green biomass of young barley plants exhibited statistically significant higher activity of superoxide dismutase (SOD) and catalase (CAT) at sampling I (in the phase of plant development DC 29) compared to the later sampling II (DC 31). Significant effects of varieties, years and interactions of the studied factors on the activity of the studied antioxidants were determined. During the experiment period (2005-2007), the variety Sebastian provided statistically significant higher average SOD activity (486 U.g-1) versus the variety Malz (416 U.g-1 dry matter) and line KM1910 (418 U.g-1 dry matter). No statistically significant difference was recorded between the latter two varieties. Average catalase activity of the varieties did not show any significant difference. Significantly higher CAT activity in the sampling I was recorded on average of years and locations in the variety Sebastian and hull-less line KM1910 (935 and 907 U.g-1) compared to the variety Malz (675 U.g-1). We can state that green biomass of young spring barley plants taken during the growth phase DC 29 was a significant source of enzymes catalase and superoxide dismutase in the course of the experiment (2005-2007).

Akrylamid v potravinách vzniká v průběhu Maillardovy reakce a jeho prekurzory jsou redukující cukry a aminokyselina asparagin. Reakční mechanismus vzniku akrylamidu v potravinách závisí na složení potravin a na podmínkách zpracování.Akrylamid vzniká ve významném množství tepelnou úpravou potravin nad 120 °C, maximum akrylamidu vzniká při 150-180 °C. Při vyš-ších teplotách je vznik akrylamidu podstatně nižší, protože eliminační reakce je rychlejší než reakce vzniku akrylamidu.Surovinou pro výrobu sladu je ječmen, rostlina s obsahem dusíkatých sloučenin a s vysokým obsahem škrobu. V průběhu sladování se ve sladu působením enzymů zvyšuje obsah redukujících cukrů, během hvozdění dochází vlivem teploty k biochemickým změnám a vznikají melanoidinové látky. Tyto podmínky jsou velmi výhodné pro tvorbu akrylamidu. Změny hladin akrylamidu byly sledovány ve sladu a následně ve vyrobeném pivu.Obsah akrylamidu se v závislosti na typu sladu pohyboval v rozmezí 0,2-3,0 mg.kg -1 a bylo potvrzeno teplotní maximum jeho vzniku (160-170 °C). Přes jeho poměrně vysoký obsah ve sladu nebyl akrylamid detekován v žádném z analyzovaných vzorků piva. Acrylamide in food is produced in the course of Maillard's reaction and its precursors are reducing saccharides and amino acid asparagin. Reaction mechanism of the acrylamide formation in food depends on food composition and processing conditions.Acrylamide is formed in a significant quantity by heat treatment of food above 120 °C, the highest quantity of acrylamide is created at 150-180 °C. At higher temperatures acrylamide creation is substantially lower as the elimination reaction is faster than that producing acrylamide.Raw material for malt production is barley, a plant with content of nitrogen compounds and high content of starch. During malting enzymes increase the content of reducing saccharides in malt, during kilning biochemical changes are induced by temperature, and melanoid substances originate. These conditions are favorable for acrylamide creation.Changes of acrylamide levels were followed in malt and subsequently in the produced beer. Acrylamide content varied depending on the type of the malt in the scope of 0.2-3.0 mg.kg -1 and thermal maximum of its origin (160-170°C) was confirmed. Despite its relatively high content in malt (from 0.2 to 3.0 mg.kg -1 ), no acrylamide was detected in any of the analyzed samples of beer. Mikulíková

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The relationship between gushing and antifungal peptides in barley and malt kernels was examined for five barley varieties produced in the Czech Republic with four conditions of infection and treatment. Proteome changes during pathogen-seed interaction were observed with SDS-PAGE and MALDI-TOF MS. These methods were applied as a fast screening for observing the relationship between gushing and peptides/proteins. It was found that the presence of basic peptides, presumably hordothionins and non-specific lipid transfer protein type 1, did not correlate with the degree of gushing for malt (|r|Ao0.07, 0.344), (|r|Ao0.01, 0.494), respectively, as detected by both methods. IntroductionCereal grains are the major source of dietary nutrients all over the world. Barley (Hordeum vulgare L.) is an ancient cereal, which, upon domestication, has evolved from largely a food grain to a feed and malting grain. Barley food use today remains important in some cultures around the world, particularly Asia and northern Africa, and there is renewed interest throughout the world in barley food because of its nutritional value [1]. Barley serves as an important model plant specie for numerous studies in malting and brewing chemistry [2]. Hence, there is an effort to assess product quality by analysis of the primary raw material, barley.Beer quality can be defined in terms of physical and sensory attributes. Pathogen infection on barley is often associated with many aspects of beer quality, e.g. gushing [3]. The term gushing is the uncontrolled release of carbon dioxide occurring when a bottle is opened and beer/foam gushes out; it is related mainly not only to beer, but also to non-alcoholic beverages [4]. Two types of gushing are described in beer. The primary gushing relates to fungal metabolites, i.e. gushing factor, which are present in malt or in other cereal raw materials of beer. The secondary gushing so-called non-malt related can be induced by production factors as are rough bottle surface, carbon dioxide supersaturation, high concentration of heavy metals, high content of oxalates, etc.The primary gushing of beer is associated with the grain being attacked by microscopic fibrous fungi, which is commonly caused by the Fusarium species and other genera such as Aspergillus, Rhizopus, Penicillium and Nigrospora species [4][5][6]. Gushing factors produced by fungi have been studied for decades. Fungal polypeptides (16.5 kDa hydrophobic peptides with eight disulphide bonds) [6][7][8] are produced and secreted by fungi and are involved in the formation of infection structures among other things [6,9]. This may explain that interaction of the fungi with substrate (in this case barley) was required for gushing occurrence [10]. Axcell et al. [11] suggested that gushing may be induced by antimicrobial peptides produced by barley in response to microbial contamination. Hippeli and Elstner [12] suggested that the gushing factor can/could be the member of the non-specific lipid transfer protein (nsLTP) multigenic family of proteins. Barle...