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Physiological storage disorders cause significant economic losses in a number of commercially important pome fruit varieties worldwide. Under the same storage conditions with the same cultivar, the incidence and frequency of disorders may vary in different years in a manner that must be explained by an interaction of pre-harvest and post-harvest factors. Major factors known to influence disorder incidence include annual weather pattern, management in the orchard, such as leaf-fruit ratio, calcium content of the fruit, harvest date and storage conditions. So far, the occurrence of the disorders cannot be predicted with certainty, and thus to adapt the management in the orchard or in the storage facility accordingly. Analysis of large amounts of data using Artificial Intelligence (AI) offers new opportunities to link large data sets into a meaningful context. The aim of the present work is the small-scale and non-destructive monitoring of fruit development in orchards under the above mentioned management practices. AI prediction models were created for the cultivar 'Braeburn'. 'Braeburn' is most susceptible to physiological storage disorders which cause browning in the fruit tissue below the skin. With tent-like constructions over the fruit trees, in which the temperature was controlled during two fruit physiologically important periods (petal drop to T-stage, three weeks before harvest), the temperature influence on disorder incidence was investigated. To the best of our knowledge, this was the first time that different temperature profiles could be generated in the orchard for mature 'Braeburn' trees. Thereby a positive influence on the reduction of internal browning caused by warm night temperatures (>10°C) before harvest was observed. Overall, each trial year showed different occurrences of physiological disorders. Orchard management and weather conditions resulted in significantly different fruit growth patterns and optical non-destructive point spectroscopy. The bi-weekly spectroscopy measurements on the same fruit and subsequent use in Partial Least Square Regression (PLSR) models were tested for their informative value. Additionally, the future fruit state was predicted in models based on weather data. The statistical evaluation of three years of data showed that the number of destructive soluble solids content (SSC) samples required to be collected each year for the {PLSR} models with an acceptable error rate was 100. These samples in particular needed to include the range of low and high SSC values. An unbalanced laboratory error of 0.1-1.0 °Brix had no influence on the modeled SSC values. Compared to destructive SSC determination in the laboratory, SSC could be non-destructively determined with an average deviation of 0.5 °Brix. Field measurements after a rain event had no influence on visible spectral indices. However, orchard covers such as rain protection over the fruit trees led to lower water absorption values at 975 nm. The separation of data on a tree-sector level in this work was performed manually, but initial steps were taken to display fruit growth and spectroscopy data via GPS signal location within a map. The acquisition of small-scale data at the tree-sector level revealed significant differences for SSC, chlorophyll and anthocyanin indices as well as significant differences in the incidence of physiological disorders. In future research and modeling approaches the tree sector information should be taken into account, even if this is not yet feasible to implement in a completely automated system under the given circumstances. The prediction models for the development of physiological disorders (core browning, cavities) were able to predict with two years of data the development of the disorders in the storage and the fruit flesh firmness at harvest 90 % correctly. Further research using non-destructive fruit measurements in orchards and the influence of weather conditions will provide further insights into apple quality improvement.
Wildunfälle stellen deutschlandweit und insbesondere in waldreichen Bundesländern wie Hessen zeitweise bis zu einem Drittel der Gesamtunfälle dar. Im Mittelpunkt der vorliegenden Dissertation steht die folgende Forschungsfrage:
Welche Parameter bestimmen die raum-zeitliche Verteilung von Wildunfällen und wie können Entscheidungsträger aus Politik, Wirtschaft und Verbänden aktuell und angesichts der technologischen Entwicklung eine bestmögliche Senkung der Unfallzahlen herbeiführen?
In einem zweiteiligen Ansatz wird zunächst eine Analyse der seitens der hessischen Polizei aufgenommenen Unfalldaten der Jahre 2006 bis 2016 durchgeführt, um Hypothesen zu den Einflussfaktoren zu beantworten. Aufbauend auf einem Forschungsprojekt der Bundesanstalt für Straßenwesen (BASt) werden die zehn gravierendsten hessischen Schwerpunktstrecken ermittelt und für diese eine Umfeldanalyse mit behördlichen GIS-Daten durchgeführt. Die Ergebnisse werden mit den Werten von zufallsbasiert gewählten, unfallunauffälligen Abschnitten verglichen. Weiterhin werden die o. g. über 170.000 Unfallreporte ausgewertet. Die Resultate der Analysen werden anhand der Fachliteratur mit dem aktuellen Stand der Forschung verglichen. Im zweiten Schritt wird die in die Unfallpräventionsarbeit involvierte Akteurslandschaft mittels Szenariotechniken zur Strategieentwicklung untersucht. Anhand der gewonnenen Erkenntnisse über die Dynamiken und Potenziale wird ein Handlungskonzept erarbeitet und mit Vertretern der Stakeholder diskutiert. Abschließend werden auf der Grundlage des in den beiden Arbeitsschritten gewonnenen Wissens Entscheidungsgrundlagen und Handlungsempfehlungen für die beteiligten Akteure erarbeitet.
Den deutlichsten Einfluss auf das Unfallrisiko hat der Faktor Dämmerung, während der sich je nach Tierart bis zu zwanzigmal so viele Kollisionen als über vergleichbare Zeitspannen bei Tageslicht ereignen. In der Analyse der jahreszeitlichen Verteilung zeigen sich zudem deutliche Schwerpunkte während der Paarungszeiten und Revierkämpfe. Hinsichtlich der Landschaftsmatrix führen erhöhte Anteile von Landwirtschafts- und Waldflächen nicht zwingend zu der Entstehung von Unfallschwerpunktstrecken, vielmehr muss die individuelle Komposition der Örtlichkeit untersucht werden. Die Nähe von großen Fließgewässern und Seen hingegen bewirkt einen steigernden Einfluss auf die Unfallzahlen. Dichteunterschiede der Wildunfallhäufigkeit je nach Tierart zeigen sich meist nur im größeren Maßstab; im Westen Hessens dominieren Reh-, im Süden Schwarzwildunfälle. Die Unfälle geschehen zu 70 % männlichen Fahrern, insbesondere in den Altersgruppen 20-24 sowie 45-50 Jahren.
Insbesondere der Herbst bietet sich für Warnaktionen an, beispielsweise durch temporär aktivierte LED-Schilder. Bezüglich der effektivsten klassischen Gegenmaßnahme, dem Wildschutzzaun, besteht die Notwendigkeit zu einer besseren Datenhaltung der Behörden sowie einer Novellierung der Richtlinie zu den Einsatzkriterien für und der Konstruktion der Zaunsysteme. Die Prozesslandschaft zeichnet sich dadurch aus, dass die meisten Akteure nur wenig Initiative zeigen und gleichzeitig lediglich geringem Handlungsdruck unterliegen. Es bestehen keine Interessenskonflikte, sondern eher zeigt sich Synergiepotenzial. Zentral ist zuallererst, die hauptsächlich organisatorischen Aufgabenstellungen wie ein übergeordnetes Großprojekt zu starten und eine zentrale Open-Data Meldeplattform einzurichten. Hier sind die Politik und Einrichtungen wie die Bundesanstalt für Straßenwesen gefordert. Nur mit ihrer Initiative können klassische Maßnahmen optimiert, innovative Lösungen in Kooperation mit der Automobilindustrie und IT-Dienstleistern eingeführt und das volle Potenzial der sich aktuell weiterentwickelnden Technologie zur Unfallprävention ausgeschöpft werden.
In den Jahren 2011 und 2012 wurde im Versuchsfeld am „Thüngersheimer Scharlachberg“
des Sachgebietes Weinbaumanagement der Bayerischen Landesanstalt für Weinbau und
Gartenbau bei der Rebsorte Silvaner kontinuierlich das Wasserpotential mittels
temperaturkorrigierter In-situ-Psychrometer gemessen. Ziel der durchgeführten Arbeiten war
es, die Wasserpotentialdynamik von Reben an ihrem natürlichen Standort und die
Pflanzenreaktion auf wechselnde Witterungseinflüsse zu untersuchen. Zusätzlich wurde die
Veränderung der hydraulischen Leitfähigkeit der Gesamtpflanze bei unterschiedlichem
Evaporationsanspruch und Bodenwasserstatus betrachtet. Die kontinuierliche
Wasserpotentialmessung an Reben wurde in den Versuchsjahren am Rebstamm und an
traubentragenden einjährigen Trieben durchgeführt. Dabei konnte festgestellt werden, dass
sich das Messgewebe des Triebes besser eignet, um das Wasserpotential über einen längeren
Zeitraum kontinuierlich mittels In-situ-Psychrometer an Reben zu ermitteln. Anhand der
Tagesgänge ließen sich deutliche Beziehungen zwischen der Wasserpotentialdynamik und
den verschiedenen Witterungsfaktoren feststellen. So hatten die beiden Faktoren VPD und
Temperatur den größten Einfluss auf das Stammwasserpotential der Reben. Dementgegen
wurde zwischen der Globalstrahlung und dem Stammwasserpotential kein Zusammenhang
ermittelt. Der engste kurvilineare Zusammenhang wurde jedoch zwischen dem VPD und dem
Wasserpotentialgradienten, der treibenden Kraft für den Transpirationsstrom der Pflanze,
ermittelt. Der Einfluss des Bodenwasserstatus auf die Stammwasserpotentialdynamik der
Reben war relativ gering. Große Unterschiede im Wasserpotentialverlauf des Tages wurden
durch eine Rebenbewässerung induziert. Demnach führte der verbesserte Wasserstatus zu
einem reduzierten Potentialgradienten der bewässerten Reben zur Aufrechterhaltung der
Transpiration im Vergleich zu den nicht bewässerten Reben.
In den Jahren 2011 bis 2013 wurde Exaktversuch zur Prüfung der Auswirkungen einer
Rebenbewässerung mit bestimmten Bewässerungsschwellenwerten durchgeführt. Ziel dieses
Feldversuchs war es, den Einfluss verschiedener Bewässerungsmethoden und
Bewässerungsintensitäten auf die generative und vegetative Wuchsleistung der Rebsorte
Silvaner zu untersuchen. Das versuchstechnisch vorgegebene Bewässerungsmanagement der
Varianten moderate Überflurbewässerung, intensive Überflurbewässerung, moderate
Unterflurbewässerung und intensive Unterflurbewässerung wurde mittels des
frühmorgendlichen Wasserpotentials exakt gesteuert. Gleichzeitig wurde innerhalb des
Versuchsfeldes der Verlauf der Bodenfeuchtigkeit innerhalb der Kontrollvariante mittels der FDR-Technologie gemessen. Zusätzlich wurde nach der Lese von jeder Variante das C12 / C13
Stabilisotopenverhältnis, der δ13C-Wert, im Mostzucker ermittelt. Um den Einfluss der
verschiedenen Bewässerungsintensitäten und -methoden auf die generative und vegetative
Wuchsleistung zu untersuchen, wurden die erzielten Traubenerträge, Mostgewichte (°Oe),
Mostsäuren und Schnittholzerträge bestimmt. Der Bewässerungsversuch zeigte auf, dass eine
Zusatzbewässerung bei der Rebsorte Silvaner einen starken Einfluss auf das vegetative
Wachstum ausübte und kein signifikanter Einfluss auf die erzielten Traubenerträge
festzustellen war.
Großprojekte der Verkehrsinfrastruktur sind komplex und beeinflussen Schutzgüter in hohem Maße; sie besitzen somit in aller Regel eine starke Relevanz für Ziele des Naturschutzes. Die Komplexität hat zur Folge, dass planerische Entscheidungen unter hohen Risiken und nicht dergestalt abgewogen werden, wie dies u.a. gemäß dem Gesetz über die Umweltverträglichkeitsprüfung (UVPG) erforderlich ist. Die vorliegende Dissertation geht der Frage nach, wie mit dieser Komplexität umgegangen werden kann, um den Erfolg der Vorhaben zu optimieren.
Brettanomyces infections represent one of the major red wine quality spoilers affecting the industry worldwide and will most likely continue to be so in the years to come. When attempting to correct or “cure” a Brettanomyces tainted wine, the most problematic metabolites to be removed are volatile phenols, particularly 4-ethylphenol.
Molecular imprinting represents one of the technologies which promise to bridge the gap between the precision and selectivity of chemical analytical methods for investigating liquid matrices, and that of industrial filtration and separation technologies currently in use.
In this work, the removal of 4-ethylphenol from wine with the aid of molecularly imprinted polymers was studied. Overall, the materials investigated in this work show promise when investigated in lab-scale conditions with model solutions. They can be effective in treating wine if the treatment conditions are appropriate and involve multiple regeneration steps.
Grapevine physiology and berry composition are highly influenced by abiotic factors, and this, in turn, affects wine composition and aroma. Primary metabolites, like sugars and acids, and also secondary metabolites, like phenols and terpenes, are sensitive to climatic conditions. However, the developmental stage of the berries
and the environmental conditions within the bunch zone play a crucial role determining the different pathways of the metabolites and hence its concentration.
This study aimed to investigate the influence of abiotic factors on the composition of berries, juice and wine of Vitis vinifera L. cv. Riesling.
Field experiments were carried out in an experimental site of Hochschule Geisenheim University [Eibinger Magdalenenkreuz, Germany (49° 59’20’’ N; 7° 55’56’’ E)] using Riesling [clone 198–25Gm; grafted on rootstock SO4 Gm47 (Vitis berlandieri x V. riparia)]. In a non-irrigated vineyard, planted in 2007, the vines were trained to a vertical shoot position canopy system. The impact of global
warming and rising temperature was one of the main questions of this thesis, and was simulated by an open heating system (OHS) in the vineyard. The tent-like construction passively heated the bunch zone. The effect of higher sun exposure on berries was trialed by the defoliation of the bunch zone at different stages of berry
development. The removal of leaves around bunches is commonly used in coolclimate viticulture to improve the health status of berries and influence the aroma profile. Due to the increasing numbers of sunshine hours as well as the rising temperatures caused by climate change, the question then arises if in future defoliation practices will be the method of choice. Additionally, and in contrast, some
bunches were placed in light-excluding boxes to simulate full shading.
On days with high radiation, the open heating system clearly elevated temperatures compared to the control and the defoliation treatments. In the bunch zone above the open heating system, the air temperature was 4 °C higher compared to the other treatments. Inside the open heating system, the temperature was up to 13 °C higher.
On days with low radiation, there was a minimal temperature difference between the treatments.
The porosity of the bunch zone was quantified by a novel approach using lightsensitive films which provide a simple and accurate method for characterizing light conditions and quantifying cumulative radiation within the canopy. Different lightsensitive
film qualities allow the measurement over a short period (3-7 days) or a more extended period (1-3 weeks). One of the significant advantages of this method will be that simultaneous measurement of several points will be possible.
The health status of the berries was improved by defoliation and the infection (incidence and severity) of Botrytis cinerea reduced compared to the control providing a faster drying of bunches after morning dew or rainfall. Similarly, the OHS promoted airflow inside the bunch zone, causing same effects.
Higher temperatures significantly reduced the berry weight, with the effect more pronounced if higher temperatures occurred before véraison. Berries grown under higher temperatures showed lower total soluble solids and the glucose to fructose ratio was impacted by lower glucose concentrations. A change in the glucose to fructose ratio will be of relevance for the fermentation since most yeasts prefer glucose over fructose. Defoliation treatment had no impact on the total soluble solids. In contrast, intense radiation or shading did not affect the berry size while extreme shading of the bunches reduced total soluble solids.
Tartaric acid was not significantly influenced by higher temperatures or radiation, but malic acid concentrations strongly declined under warmer conditions. This decreased the total acidity in juice and wine, which is of particular importance for the wine profile of Riesling. The defoliation practices showed only little effect on the acid concentrations whilst the extreme shading treatments strongly increased the acidity.
The analysis of phenols in berry skin was performed by high-performance liquid chromatography (HPLC) coupled to a photodiode array (PDA) detector and quantified with an external calibration. Flavonols, in particular, were influenced by higher sun exposure, with significantly higher flavonol concentrations found in the
defoliation treatments. The time point when defoliation was applied had only small effects on the final total flavonol concentration. On the other hand, when a sunny period occurred after véraison flavanols revealed high concentrations after defoliation. Sunny periods before véraison or a ripening period with low sunshine
hours did not increase the flavanol concentration compared to the control. No impact of the defoliation on the group of hydroxycinnamic acids, non-flavanoids, was The sensory assessment with small scale-vinifications was diverse. Only in the younger vintage, the panellists were able to detect differences in wines, which were mainly based on total acidity.
The influence of the treatments to the grapes, which were observed for primary and secondary metabolites in berries and juice, were found in wine as well. The only expectation was TDN. In wines, higher TDN concentrations were always detected for the late defoliation. The early defoliation contained higher TDN concentrations if a sunny period occurred before véraison. Also, elevated temperatures caused higher TDN levels in wine. The prediction of the precise temperature and light conditions influencing TDN will require detailed investigations.
A new approach was developed to analyse and quantify free and glycosidically bound monoterpenes and C13-norisoprenoids in berries, juice and wine. The sample volume was reduced by 90% and free analytes were directly analysed from the matrix with only little sample preparation. This simplified the analysis, saved time
and made the use of organic solvents and solid-phase extraction cartridges redundant. The method was validated and compared to other methods in literature.
In juice and wine 15 monoterpenes and four C13-norisoprenoids could be analysed simultaneously and the typically concentration ranges of the samples were covered.
Wine from Vitis vinifera cv. Riesling grapes is one of the most internationally
renowned white wine styles worldwide. There are several aroma compounds that are fundamental to the sensory properties of Riesling wines. Two such classes of compounds are monoterpenes and C13-norisoprenoids, both of which can be influenced in the vineyard, the winery and in the bottle. The overall objective of this study was to investigate the role of certain vineyard and winemaking practices on the development of sensorial important flavour compounds in Riesling, with particular emphasis on 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN).
Chapter 2 investigates the effect of a manipulated light environment during grape ripening on Australian Riesling over two consecutive vintages. The application of coloured shade cloth was used to alter not only the quantity of light but also the quality of light reaching grape leaves and berries. Changes in both grape and wine composition were observed. A reduction solely in the quantity of light resulted in a significant reduction in free and total TDN concentrations. However, sensory descriptive analysis of finalised wines demonstrated a conflicting result, as increased ‘kerosene-like’ aroma (a common descriptor for TDN) was not always linked to higher TDN concentrations.
The starting point of TDN formation is the availability of its precursors;
carotenoids and their subsequent glycosylated breakdown products. Chapter 3 comprises the analysis of major grape carotenoids present in grapes under various light conditions. While several complex mechanisms involved in photosynthesis and notably the photoprotection triggered by different light qualities during the ripening period were observed, the reduction in concentration of carotenoids was significantly higher in sun-exposed samples compared to other treatments during grape ripening.
The degree of carotenoid degradation could be a useful marker for the decision
regarding TDN management in wine during winemaking or storage. Furthermore, Chapter 3 provides results from the analysis of C13-norisoprenoid glycosides in wines made from grapes grown under different shade cloth in correlation to their corresponding TDN concentrations. For this experiment two approaches were considered, firstly the untargeted profiling and then targeted analysis of the glycosides in wine. Glycosides related to TDN evolution in wine were tentatively identified.
While trials conducted in Australia evaluated the effect of shading on the evolution of important grape and wine components in Riesling, Chapter 4 describes
the significance of increased solar exposure (leaf removal) on Riesling grape and wine
compositional behaviour in combination with different row orientations (East-West,
Northeast-Southwest, North-South) under German field conditions.
Microclimatically, East-West orientated rows maintained the lowest interior canopy
light interception, Northeast-Southwest and North-South orientations lead to the
highest light exposure values, peaking in the morning and afternoon, respectively.
Pronounced differences in secondary metabolites were found between the different
exposure levels introduced by leaf removal. Highly exposed grapes showed significantly higher bound and free TDN concentrations, however, no direct correlation was observed between elevated free TDN levels and the perception of ‘kerosene-like’ aroma in the wines.
Finally, Chapter 5 comprises a comparative analysis of oenological practices of grape pressing and yeast selection including enzyme (β-glycosidase) addition on the extraction of TDN and related C13-norisoprenoids in finished wines. Insignificant differences were observed between the effect of whole-bunch and crushed/destemmed fruit pressings. While the choice of yeast during alcoholic fermentation did not affect TDN formation, the addition of glycosidases to musts resulted in an approximately 15% to 25% increases in free TDN concentrations after the wines were submitted to accelerated ageing. However, these changes were negligible when compared to the consequence of viticultural management practices.
This thesis represents a valuable contribution to the understanding of the formation, management and sensory contribution of TDN in Riesling. Furthermore, this study investigated for the first time the effect of different light regimes (shade cloth) on TDN evolution which can be used to advance the management of Riesling grape production, especially during hotter summers.
A substantial area of the terrestrial surface is used for agricultural production. In Europe, many farmland species and ecosystems have evolved with traditional agricultural practices and rely on extensive cultivation for their survival. Today, agrobiodiversity is threatened by the abandonment of traditional agricultural land use.
The cultivation of wine is one of the oldest forms of agriculture. On steep slopes, viticulture has shaped landscapes, cultural traditions, and unique ecosystems in many regions. In Germany, steep slope viticulture has been declining dramatically in recent decades due to insufficient profitability. The abandonment of these traditional cultural landscapes threatens the cultural heritage and the flora and fauna adapted to viticultural management. One solution to halt the decline of steep slope viticulture could be a change of cultivation system from vertically oriented rows to modern terraced vineyards. Here, the rows run parallel to the hillside, facilitating cultivation, and thus reducing production costs. At the same time, a large portion of terraced vineyard consists of uncultivated embankments, which can provide valuable habitats within the agricultural system. However, little is known about the effects of a cultivation system change and vineyard abandonment on biodiversity. In addition, information on how to sustainably revegetate terrace embankments is missing.
Within the framework of this dissertation, the overall aim was to evaluate the potential of terraced vineyards to promote biodiversity and investigate measures for sustainable revegetation of terrace embankments. In addition, the effects of distinct vineyard management (vertically oriented vs. terraced) and vineyard abandonment on biodiversity were assessed. The main part of this thesis is based on a field study comparing three vineyard types (vertically oriented vineyard, terraced vineyard, abandoned vineyard) that were arranged in 15 triplets along the Upper Middle Rhine Valley (UMRV) in Germany. The effects of vineyard types, local vineyard parameters, and landscape structure on biodiversity were evaluated using four species groups. Studied groups represented plants and arthropod species (grasshoppers, wild bees, spiders). In a second field study, three newly constructed terrace embankments were revegetated using different seeding techniques and seed mixtures. In addition, measures to support plant establishment were evaluated. Plant establishment was assessed for three consecutive years in permanent vegetation plots.
The first study on the three vineyard types revealed that there was no uniform positive effect of one vineyard type on all investigated groups. Instead, the responses were group and taxon-specific and driven by management-related disturbance intensities, local vegetation structures, soil and landscape structure. In total, the heterogeneous landscape and small-structured vineyard agroecosystem of the UMRV supported high species diversity, hosted high numbers of rare and threatened species, and diverse species communities across vineyard types. Plant species richness was enhanced by vineyard management and particularly benefited from terraced vineyards and rather nutrient-poor and extensively managed embankments. In comparison, plant communities of fallows were completely different with lower plant diversity. Grasshoppers were supported by vineyard management, and bare ground in vineyard inter-rows supported heat- and open-adapted species. Taller vegetation stands on terrace embankments enhanced grasshopper species richness while woody structures and vineyard abandonment reduced grasshopper diversity and abundance at the local and landscape scale. Wild bee species richness and abundance were strongly determined by their nesting needs. For ground-nesting bees, the suitability of soils for nesting was important, irrespective of vineyard management types whereas above-ground nesting bees were enhanced by woody structures of fallows at the local and landscape scale. Moreover, fallows further provided valuable floral and non-floral resources for both ground- and above-ground nesting bees. For spiders, there was no difference in species richness and abundance between vineyard types but many xerophilic species adapted to open habitat structures prevailed in terraced vineyards. Vineyard fallows supported highly distinct spider communities, including some late-successional species. In conclusion, the vineyard cultural landscape of the UMRV with both actively managed and abandoned vineyards led to a high diversity of plant and arthropod communities. Hence, for its preservation, a spatially heterogeneous landscape comprising both (semi) natural and viticultural-management elements is important.
Results from the second study showed that terraced vineyards and especially terrace embankments can contribute to promoting biodiversity, especially if they are revegetated with regional seed mixtures. Seeds of locally adapted populations and hydro-seeding provided higher vegetation cover which is needed to prevent severe erosion whilst non-locally adapted standard seed mixtures and manual seeding had a higher failure risk and were more prone to severe precipitation events. Taken together, vineyard terracing appears to be a win-win solution for both winegrowers and biodiversity and thus helps to maintain viticulture on steep slopes.
Die vorliegende Arbeit befasst sich mit der Herstellung von Würzen und Bieren mittels eines neuartigen Sudprozesses aufgrund einer integrierten, dynamischen Läutertechnologie und dem qualitativen Vergleich zu herkömmlichen Systemen. Das Sudhaussystem OMNIUM by Ziemann® mit dem darin implementierten neuartigen Maischefiltrationsverfahren NESSIE by Ziemann® produziert Würzen, deren Zusammensetzung sich von herkömmlichen Würzen unterscheidet. Erhöhte und erniedrigte Konzentrationen bestimmter Inhaltsstoffe im Vergleich zur herkömmlichen Würzebeschaffenheit verändern die Hefeversorgung und konsequenterweise das fertige Bier. Ziel der vorliegenden Arbeit ist es, den Einfluss auf die Würzezusammensetzung sowie das Herauslösen bestimmter Inhaltsstoffe durch die konventionelle und neuartige Sudhaustechnologie zu bilanzieren, zu vergleichen und die Auswirkungen auf den gesamten Brauprozess zu untersuchen.
Hierzu werden ober- und untergärige Biere mittels eines konventionellen und neuartigen Sudwerks im 30 l-Maßstab hergestellt. Die entstehenden ungekochten und gekochten Würzen und die hieraus produzierten Biere werden umfassend analysiert. Hierbei werden neben den Prozessparametern wie Extrakt und pH-Wert, Kohlenhydrate, Gerbstoffe, Eiweißfraktionen, Fettsäuren sowie Mineralstoffe und der photometrische Jodwert erhoben. Die anfallenden Treber werden ebenfalls untersucht. Die Schaumstabilität des fertigen Bieres wird untersucht und das Bier mittels einer Flavournetzverkostung bewertet. Die Ergebnisse dieser Sude bilden den Basisvergleich der Sudhäuser und die Grundlage der weiterführenden Vertiefung.
Die weiterführenden Untersuchungen befassen sich mit dem aufschließbaren Extrakt der Treber des Drehscheibenfilters, dem photometrischen Jodwert und der Enzymaktivität von Würzen, einer möglichen Reduktion der Trubfracht der neuartig hergestellten Würzen, der chemisch-physikalischen Stabilität sowie der Geschmacksstabilität der hergestellten Biere, den Gerbstofffraktionen und deren Einfluss auf die Fermentation und der Verarbeitung verschiedener Rohstoffe und Rohstoffqualitäten mittels des Drehscheibenfilters. Abschließend wird eine theoretische Modellierung der Maischefiltration mittels eines Drehscheibenfilters erstellt und ein Scale-Up der gewonnenen Daten auf Industriegröße durchgeführt. Für die untergärige Fermentation der neuartig hergestellten Würzen wird ein Leitfaden zur Anpassung der Gärungsparameter erstellt.
Die Auswertung der Ergebnisse zeigt, dass sich durch den Drehscheibenfilter im neuartigen Sudhaus im Vergleich zum konventionellen Sudhaus eine Erhöhung des Mineralstoff- und des Fettsäurespektrums und eine Verringerung des Gerbstoffzusammensetzung ergeben. Die stickstoffhaltigen Verbindungen sowie das Zuckerspektrum bleiben unverändert. Die neuartige Würzebeschaffenheit ermöglicht eine um zwei Tage zügigere und intensivere Fermentation. Durch die gesteigerte Hefevermehrung wird mehr Maltose und Maltotriose sowie Zink und Kalium aufgenommen. Dies bewirkt einen höheren Endvergärungsgrad der Biere. Die gute Versorgung der Hefe führt zu einem tendenziell niedrigeren Gärungsnebenproduktespektrum, was durch ein angepasstes Gärverfahren korrigiert werden kann. Die Deckung der Verkostungsergebnisse zeigt, dass die Herstellung geschmacklich gleicher Biere mit den unterschiedlichen Sudhäusern möglich ist. Durch das signifikant niedrigere Gerbstoffspektrum im Bier wird deutlich, dass eine gerbstoffseitige Stabilisierung im neuartig hergestellten Bier zu überdenken ist. Ein Einfluss der Gerbstoffe auf den Hefemetabolismus konnte ausgeschlossen werden. Insgesamt ist die chemisch-physikalische Stabilität und Geschmacksstabilität der neuartig hergestellten Biere als sehr gut zu bewerten. Die Schaumstabilität unterscheidet sich nicht zu konventionell hergestellten Bieren. Die signifikant höhere Würzetrübung ist im Bier nach der Sedimentation mit der Hefe während der Gärung nicht wieder zu finden. Zusätzlich kann großtechnisch die Trubfracht ohne Beeinträchtigung der Inhaltsstoffe mittels einer Zentrifuge verringert werden. Es zeigt sich, dass der photometrische Jodwert unabhängig des Einsatzes eines heißen Malzauszuges über die Fermentation hinweg absinkt. Ein direkter Zusammenhang mit der enzymatischen Aktivität des heißen Malzauszuges konnte nicht nachgewiesen werden. Prinzipiell ermöglicht die dynamische Siebfiltration mit der angeschlossenen diskontinuierlichen Extraktion die Verarbeitung verschiedener Rohstoffe und verschiedener Rohstoffqualitäten. Die Ergebnisse sind auf den industriellen Maßstab übertragbar.
Climate change cannot currently be ignored and impacts all fields of agriculture. IPCC reports forecast an increase of up to 700 ppm of atmospheric carbon dioxide concentration at the end of the 21st century. Parameters such as elevated global temperature, reduced precipitations in certain areas of the world and increase of atmospheric carbon dioxide concentration are modifying plants’ environment. Grapevine, which is a crop of economic and cultural importance, is very sensitive to climate modifications. The effects of temperature or water stress on grapevine has been widely investigated, and elevated carbon dioxide has been mainly studied in enclosed systems such as greenhouses. However, the impact of increased concentration of carbon dioxide on plants in open-field experiments remains scarcely studied because of the technical challenge that it represents. In this context, the aim of this PhD work was to investigate the impact of elevated carbon dioxide concentration using the set-up VineyardFACE located at Geisenheim University. This open field set-up enables to apply a moderate and gradual increase (+20%) of ambient carbon dioxide concentration on two grapevine cultivars, Riesling, and Cabernet Sauvignon. While knowing the impact of elevated carbon dioxide treatment on leaf physiology and vegetative growth from previous studies (Wohlfahrt et al., 2018), as well as on berry composition during the early years of fumigation, the goal of this study was to determine the effects of elevated carbon dioxide treatment on agronomical traits, primary metabolites (sugars, organic acids, amino acids) and secondary metabolites (anthocyanins, terpenes) on vines undergoing six years of fumigation, as well as monitoring berry development and following berry ripening for successive seasons. Intermediates from central metabolism were also studied for two years (2020 and 2021), and terpene analysis was realized on Riesling must 2021.
Our results showed that although photosynthesis was still enhanced, little effects were found of elevated carbon dioxide treatment on primary metabolites as well as on berry ripening rates, for successive seasons for both Riesling and Cabernet Sauvignon. However, a trend of reduced total anthocyanins concentration in Cabernet Sauvignon was demonstrated by elevated carbon dioxide treatment mainly in 2020, while anthocyanins composition remained fairly similar. Terpenes (both bound and free) composition in Riesling in 2021 was not impacted by elevated carbon dioxide treatment.