Search

Mykotoxine sind sog. Sekundärmetabolite verschiedener Schimmelpilzgattungen, die nach Verzehr entsprechender Mengen bei Mensch und Tier Vergiftungen hervorrufen können. Im Rahmen dieser Arbeit wird die Bedeutung der Mykotoxine Deoxynivalenol und Ochratoxin A im allgemeinen aufgezeigt. Des weiteren werden die bisher zu diesem Thema im Zusammenhang mit der Bierbereitung veröffentlichten Arbeiten und deren Ergebnisse im speziellen und chronologisch dargelegt. Im Mittelpunkt des praktischen Teils steht die Bilanzierung von Konzentrationsänderungen der genannten Toxine in allen Stufen der Bierherstellung um bestehende Lücken zu schließen und Möglichkeiten der sog. „Maskierung“ dieser Substanzen offen zu legen. Dazu wurden neben Screenings von Praxisproben auch Modellversuche und Untersuchungen im praxisrelevanten Pilotmaßstab sowohl mit Toxin-Reinsubstanzen als auch mit natürlich belastetem Weizen sowie Gersten- und Weizenmalzproben durchgeführt. Neben neuen Erkenntnissen zum Verlauf besagter Toxinkonzentrationen während des Maischens und der Gärung konnten auch Maskierungen nachgewiesen und im Versuch dargestellt und belegt werden. Untersucht wurden auch die Kohlenhydrat- und Aminosäurespektren gärender Würzen sowie der Einfluss der beiden Mykotoxine auf Wachstum und Gäraktivität von Hefen. Aufgrund der erzielten Resultate können gewisse Vorhersagen über zu erwartende Konzentrationen in Praxiswürzen und –bieren, die Adsorption und Verschleppung der Toxine durch Erntehefe sowie Aussagen zur Übertragbarkeit von Modellversuchen unter Verwendung von Reinsubstanzen auf die Praxis gemacht werden. Mycotoxins are so-called secondary metabolites of different species of moulds that can cause poisoning in humans and animals after consumption of according quantities. The present paper shows the relevance of the mycotoxins Deoxynivalenol and Ochratoxin A in general. Furthermore it lists the papers published hitherto concerning mycotoxins in the brewing process and their results individually and in chronological order. The practical part of the present paper focuses mainly on measuring the development of changes in concentrations of the above-mentioned toxins in all stages of the brewing process in order to fill existing gaps of knowledge and prove possibilities of the so-called "masking" of those substances. To this effect, in addition to screenings of samples taken from production batches, experiments and examinations on a pilot brewing scale with relevance to practical conditions were carried out both with crystalline toxins and naturally contaminated wheat as well as samples of barley and wheat malts. Apart from new insights into the development of the above-mentioned toxin concentrations during mashing and fermentation, maskings could be detected and be demonstrated and proven in trials. Moreover the carbohydrate and amino acid spectra of fermenting worts and the influence of both mycotoxins on growth and fermentation activity of yeasts were examined. Based on the results obtained, certain prognoses about toxin concentrations to be expected in production worts and beers, about adsorption and carry-over of the toxins by harvested yeast and statements concerning the applicability of experiments using crystalline toxins to practical conditions can be made.

While in a previous work the ESR spectroscopic detection of irradiated dried fruits was reported, in this paper liquid chromatographic determination of the carbohydrate fraction of these fruits is introduced and connected with the ESR results. After irradiation of dried fruits three different types of ESR spectra are observed. In most cases the dried fruits can be attached to these various types by means of their sugar composition. It was also found that the ESR spectra observed for sucrose-rich fruits are very similar to that of pure sucrose. The structure of the ESR spectra can change with storage. Probably, radical rearrangement reactions in the samples are responsible for these changes.

Bley is one of the pharmacists who is nearly forgotten today. His scientific work is very extensive and diversified (535 paper in 12 scientific journals). The present article gives a short biography and shows Bley contributions in the field of technological development (for example using of sugarbeet) in Germany in the 19th century.

The present paper deals with the nutritional value of some natural sweeteners, like concentrated fruit juices, special syrups and honey. The following aspects are discussed: concentration of sweet-tasting carbohydrates, average composition of essential nutrients like minerals and vitamins, and occurrence of other substances like organic acids etc. The nutritional value of natural sweeteners is not significantly different from "sugar" (saccharose): Natural sweeteners do not contribute to fulfill the need for minerals, trace elements or vitamins in an important manner. The sensoric properties are different and the intensity of sweet-taste is usually higher in sucrose than in syrups. Descriptions of such products as "naturally", "healthy", "without sugar" are not justified.