Immobilized wine yeast.

The paper adverts to the possibilities of the use of immobilized systems in viniculture. It describes methods of cell immobilization and elucidates patterns of the diffusion effects in the immobilized system. The immobilized wine yeast are viewed in a complex way from the aspect of biochemical, physicochemical, technological and even economical criterions. Today, the oenological modern style counts with the chances of application of biological reactors with fixed bed of immobilized yeast.(In Czech, English summary only

Veränderungen des trans 2-Hexenal-Gehalts in Rebblättern während der Vegetationsperiode

Ungesättigte Fettsäuren sind in der Rebe Vorstufen einer biologisch wichtigen Gruppe, der ungesättigten C6-Alkohole und -Aldehyde, die Bestandteile eines typischen Aromas ("green grass flavour") sind. Außer den charakteristischen sensorischen Eigenschaften schützen diese Verbindungen die Rebe vor Pilz- oder Bakterieninfektionen. Die saisonalen Veränderungen des trans 2-Hexenal-Gehalts von Rebblättern wurden von Mai bis August 1994 bei sieben verschiedenen Rebsorten untersucht. Der höchste Wert wurde Ende Juli, zu Beginn des Traubenschlusses bei der Sorte Irsay Oliver mit 4,1 g/kg Trockensubstanz festgestellt.Investigation of the trans 2-hexenal content in leaves of grapevines during the vegetation periodUnsaturated fatty acids in plants are known to be precursors of the biologically important group of unsaturated C6-alcohols and C6-aldehydes. These compounds constitute the basis of aroma components called ''green grass flavour''. On the other hand they protect grapevines against fungal or bacterial infections. Seasonal changes of the content of trans 2-hexenal in leaves of seven varieties of Vitis vinifera were investigated from May to August 1994. The highest content of trans 2-hexenal was detected in leaf samples harvested in the last decade of July when clusters started to close (cv. Irsay Oliver 4.1 g/kg dry weight)

Änderungen des Aminosäuregehaltes während der Schaumweinbildung

Die Änderung des Aminosäurengehaltes in Sektproben wurde 2, 12 und 24 Monate nach Beginn der Flaschengärung untersucht. Zum Start der sekundäen Gärung wurden zwei ethanoltolerante Saccharomyces cerevisiae - Stämme und drei aktive Trockenhefepräparate verwendet. Nach zwei Monaten konnte ein Konzentrationsrückgang des Großteils der Aminosäuren festgestellt worden. Nur Phenylalanin und Histidin batten zugenommen. Nach 12 Monaten war die Konzentration von Serin, Glycin, Alanin und Valin herabgesetzt, Prolin dagegen angereichert, ebenso wie Leucin und Histidin. Nach zwei Jahren war der Gehalt an Thyrosin, Histidin und Lysin, Leucin und Isoleucin erhöht, während eine Tendenz zur Verringerung der Konzentration von Prolin, Valin und Arginin registriert wurde. Die essentielle Aminosäure Methionin war nach 24 Monaten in allen Sektproben verbraucht.Changes of the amounts of amino acids during sparkling wine productionChanges of the amino acid content after 2, 12 and 24 months in sparkling wine samples have been investigated. Two liquid and three active dry wine yeast preparations of Saccharomyces cerevisiae strains were used for the secondary fermentation. After two months a decrease of most amino acids was observed, only the histidine content was increased. The concentration of serine, glycine, alanine and valine decreased after 12 months. In this phase, on the other hand, the proline, leucine and histidine contents increased. After two years the content of thyrosine, histidine and lysine as well as leucine and isoleucine in sparkling wines raised, while proline, valine and asparagine showed a decrease compared with the initial concentrations. The essential amino acid methionine was utilized in all sparkling wine samples after 24 months

Evaluating Discharge Regimes of Karst Aquifer

Karst springs are typical for abrupt changes of discharge immediately following recharge events. Monitored discharges of springs are used to determine quantitative variability over the period of time, showing their reliability as dependable water sources. Karst aquifers also exhibit (at least) dual ground-water flow regimes, that is, fast (conduit-dominated) flow and slow (diffuse) flow. This is something that can be observed in nature as the fast change of water amount outflowing from the groundwater source, or described by rapidly responding hydrographs, recording water levels or discharges. Selection of proper investigative techniques characterizing discharge regime properties of a karst aquifer is therefore important in order to identify possible theoretical background models describing this behaviour. On this basis, we can also find a particular method of hydrograph separation into flow components linked to the fast-flow regime, slow-flow regime, or intermediate regimes as well. With this point in mind, several quantitative methods that might be particularly useful in hydrograph analysis of water outlets from the karst aquifer system are briefly discussed here