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Evaluation of crop model-based simplified marginal net return maximising nitrogen application rates on site-specific level in maize
No full textCrop growth models such as DSSAT-CERES-Maize have proven to be useful for analysing plant growth and yield within homogenous land units. The paper presents results of newly developed model-based site-specific Soil Profile Optimisation (SPO) tools in combination with an updated version of an already published Nitrogen Prescription Model (NPM). Site-specific soil profiles were generated through an inverse modelling approach based on measured site-specific yield (point-based) and tops weight (above-ground biomass time-series) and evaluated. Site-specific soil profiles generated based only on measured yield variability were able to explain 72% (R 2 0.72) of yield variability (dependent variable) based on selected soil profile input parameters (independent variable). Site-specific soil profiles generated based on measured yield and tops variability simultaneously (multiple target variable) explained 68% of yield variability (R 2 0.68). The NPM uses the SPO generated site-specific soil profiles for economic evaluation of site-specific N application rates. NPM simulated N application rates, aiming at the maximisation of marginal net return (MNR) were 25% lower compared to the uniform N application rates with an assumed grain and N price of 0.17 and 0.3 Euro kg −1 respectively, under rainfed conditions over three years based on soil profiles generated via an inverse modelling approach only from measured yield variability (one target variable). N application rates were 28% lower when based on soil profiles generated from simultaneously included grain and tops variability in the inverse modelling approach. The results highlight the importance of site-specific fertilizer management when maximising MNR.Open Access funding enabled and organized by Projekt DEAL.BMEL; BLEFederal Ministry of Digital Affairs and TransportUniversität Hohenheim (3153
Benchmarking of secure group communication schemes with focus on IoT
No full textAs Internet of Things (IoT) devices become ubiquitous, they face increasing cybersecurity threats. Unlike standard 1-to-1 communication, the unique challenge posed by n-to-n communication in IoT is that messages must not be encrypted for a single recipient but for a group of recipients. For this reason, using Secure Group Communication (SGC) schemes is necessary to encrypt n-to-n communication efficiently for large group sizes. To this end, the literature presents various SGC schemes with varying features, performance profiles, and architectures, making the selection process challenging. A selection from this multitude of SGC schemes should best be made based on a benchmark that provides an overview of the performance of the schemes. Such a benchmark would make it much easier for developers to select an SGC scheme, but such a benchmark still needs to be created. This paper aims to close this gap by presenting a benchmark for SGC schemes that focus on IoT. Since the design of a benchmark first requires the definition of the underlying business problems, we defined suitable problems for using SGC schemes in the IoT sector as the first step. We identified a common problem for the centralized and decentralized/hybrid SGC schemes, whereas the distributed/contributory SGC schemes required defining an independent business problem. Based on these business problems, we first designed a specification-based benchmark, which we then extended to a hybrid benchmark through corresponding implementations. Finally, we deployed our hybrid benchmark in a typical IoT environment and measured and compared the performance of different SGC schemes. Our findings reveal notable impacts on calculation times and storage requirements without a trusted Central Instance (CI) in distributed/contributory SGC schemes
Technology adoption and farm performance in sub-Saharan Africa: evidence from Mozambique and Ghana
No full textIncreasing the productivity of agriculture in sub-Saharan Africa (SSA) is fundamental to achieving many of the Sustainable Development Goals (SDGs) in the region and, by extension, in the world. Given its importance to rural livelihoods and national economies in SSA, productivity growth in this crucial sector has the potential to stimulate broad-based poverty reduction (SGD 1) and further address the persistent food insecurity and malnutrition challenges (SDG 2) faced by the region. However, despite its potential for growth and importance to the region, productivity growth in agriculture has either stagnated or declined in SSA over the years. Efforts to tackle this persistent challenge have been focused on the promotion of improved technological packages and modern farming practices in various parts of the region. Nonetheless, adoption has mostly remained sluggish across SSA, stressing the continuing need for a deeper understanding of the underlying barriers to sustained adoption, as well as the effects of adopted technologies and farming practices on farm performance, particularly in terms of technical efficiency and technological gains.
The smallholder farming contexts of Mozambique and Ghana offer distinct cases for gaining useful insights into the underlying barriers to sustained adoption of modern technologies and farming practices, as well as their effects on farm performance. Specifically, despite ongoing efforts by the Mozambican government and development partners to promote sustainable intensification practices, such as integrated soil fertility management (ISFM) practices (including mineral fertilizer, improved seeds and depending on the location, organic inputs such as manure and compost), adoption remains low among farm households. As a result, resource-poor farmers often resort to unsustainable land use practices, such as shifting cultivation, slash-and-burn agriculture, deforestation and forest degradation, along with low-cost agronomic practices like crop rotation, crop residue retention and intercropping to safeguard soil fertility. However, evidence is scarcely available on the underlying barriers to sustained adoption of promoted ISFM practices, along with the technological and technical efficiency gains associated with integrating improved versus recycled seeds with agronomic practices in Mozambique.
Furthermore, one of the key challenges to technology adoption, as well as to farm performance and the long-term sustainability of agriculture, is the issue of aging farming population. This issue is particularly pressing in Ghana, where, in addition to the growing disinterest of young people in farming and an estimated life expectancy ranging from 55 – 65 years, the average age of farmers is reported to be 55. Given that the majority (73.5%) of Ghana’s population is below the age of 36, an improved understanding of how farm operators’ age influences their managerial performance and technology adoption is crucial for shaping evidence-informed policies aimed at attracting, retaining and leveraging this demographic dividend within the Ghanaian agricultural sector. From the foregoing, this thesis has three key objectives: (1) to explore context-specific evidence on the systemic barriers to sustained adoption of integrated soil fertility management (ISFM) practices by Mozambican smallholder farmers; (2) to examine the technological and technical efficiency gains associated with integrating improved versus recycled seeds with agronomic practices such as crop rotation, intercropping and crop residue management by Mozambican smallholder farmers; and (3) to assess how the age of farm operators – disaggregated into the youth, middle-aged and aged – influences their managerial performance and farm technology adoption in Ghana.
The objectives of this thesis were achieved using data from both primary and secondary sources. Relying on mixed-methods research design, qualitative data were drawn using key informant interviews (KIIs) and focus group discussions (FGDs), and quantitative data via a household survey in the Central and Northern zones of Mozambique. These primary data were used to address the first and second objectives of the thesis. Overall, 32 qualitative interviews, consisting of 8 FGDs, 5 medium- and large-scale farmer KIIs and 19 expert KIIs were conducted in Mozambique. This was followed by a household survey which was conducted in the Central and Northern zones of Mozambique, involving 607 farming households who were selected through a multi-stage sampling technique. Both datasets were collected in 2022. To address the third objective of the thesis, secondary data from two nationally representative surveys in Ghana were used. These include all seven waves of the Ghana Living Standards Survey (GLSS) which were conducted from 1987/88 – 2016/17 and the two waves of the Ghana Socio-economic Panel Survey (GSPS) conducted between 2009/10 and 2014/15. While the GLSS was implemented using a repeated cross-sectional design, the GSPS followed a panel design. Overall, 24,596 farm households across Ghana were included in the sample for analysis.
This thesis is organized into five chapters. Chapter 1 introduces the research topic by providing a general overview of the study within the global and sub-Saharan African contexts, followed by background information on agriculture and technology adoption in both Mozambique and Ghana. Chapter 2 explores the systemic barriers that continue to impede the sustained uptake of ISFM practices among Mozambican smallholder farmers. Chapter 3 evaluates the technological and technical efficiency gains associated with existing farmer practices of integrating improved versus recycled seeds with agronomic practices in Mozambique. Chapter 4 examines the relationship between farm operators’ age, technology adoption and managerial performance in Ghana. Finally, chapter 5 presents the conclusion of the thesis, outlines its limitations and makes recommendations for policy and future studies.
Chapter 2 relies on mixed-methods research design to explore the systemic barriers to sustained adoption of ISFM practices among Mozambican resource-poor farmers. Complementing content analysis of qualitative data with descriptive analysis of data from a household survey, the findings indicate that whereas Mozambican smallholder farmers have generally recognized the compelling need for ISFM practices in high-value crop production systems such as vegetables, cotton, sugarcane and tobacco, they are reluctant to make similar investments in food crops. Instead, they adopt low-cost agronomic practices such as crop residue management, intercropping, crop rotation and shifting cultivation to safeguard soil fertility in food crop systems. Evidence further shows that the use of improved seeds, mineral fertilizers and depending on the location, external organic inputs such as manure and compost, is more prevalent among three groups of Mozambican smallholder farmers: independent vegetable producers, farmers participating in contract farming schemes and those residing in districts bordering Malawi, Zambia and Zimbabwe. Additionally, despite expressing strong willingness to invest in these inputs, farmers’ access to and use of these inputs are hindered by a complex set of systemic barriers, including unfavorable market conditions which limit profitability and intensify risk; institutional limitations such as credit constraints and human capital limitations; liquidity constraints; challenges associated with key ISFM components; an existing culture of dependency shaped by past experiences of farmers with free inputs; and entrenched perceptions among both farmers and professionals that Mozambican soils are inherently “fertile” or “virgins” and “fertilizers destroy the soil”. Given these findings, the study recommends that interventions aiming to promote sustainable land use practices like ISFM in land-abundant contexts of SSA like Mozambique, should prioritize addressing these systemic barriers to ensure sustained adoption of these practices. For instance, to raise productivity in food crop systems, agrarian interventions should adopt a holistic value chain approach which goes beyond the production phase to strengthen other critical segments of the value chain, such as extending agro-dealer networks to major production areas, as well as enhancing access of smallholder farmers to output markets that offer stable and fair prices. Again, there is the urgent need to intensify education and raise awareness among both farmers and professionals to dispel the widespread misconception that fertilizers damage the soil and on the need for farmers to implement ISFM as a package rather than in isolation. Addressing these systemic constraints holds an enormous prospect for fostering the sustained uptake of sustainable intensification practices like ISFM in Mozambique.
Drawing on the findings from chapter 2, which indicates that Mozambican smallholder farmers seldom invest in purchased inputs for food crops, chapter 3 utilizes the same data to assess the technological and technical efficiency gains associated with existing farmer practices of integrating improved versus recycled seeds with agronomic practices, including crop rotation, intercropping and crop residue management in food crop systems. Relying on an endogeneity-corrected stochastic frontier and metafrontier functions to analyze the quantitative data, results from this first-stage analysis were contextualized and reinforced with evidence from the qualitative data. The findings suggest that farm households who integrated improved seeds with agronomic practices achieve a modest technological advantage (4%) relative to their peers who integrated recycled seeds with these same practices. Nonetheless, the results reveal no significant difference in technical efficiency between both groups. Instead, farm households in both groups performed these agronomic practices so poorly, such that each group could expand its total farm production by more than 50% simply by implementing these existing agronomic practices more efficiently. Consequently, the greatest potential for raising farm output in food crop systems in Mozambique lies in the capacity of resource-poor households to effectively implement these existing agronomic practices. Based on the findings, it is recommended that programs aiming to boost productivity in food crop systems in Mozambique should prioritize building the capacity of farm households to enable them implement these agronomic practices more efficiently. Encouraging resource-poor farmers to strictly adhere to recommended agronomic protocols, such as selecting the right crop mixes for intercropping and rotation, retaining crop residues on the field and using inoculants to boost nitrogen fixation in legumes can considerably enhance soil fertility and support productivity in subsequent crops.
Given the increasingly aging farming population in Ghana and the urgent need for evidence-informed policies aimed at attracting and retaining the country’s growing youth population in agriculture, chapter 4 of the thesis relies on a nationally representative data from the GLSS and GSPS to evaluate how the age of resource-poor farmers influence their farm-level decision-making in terms of technology adoption and managerial performance. Drawing on a three-decade dataset from cereal-producing households and guided by the definitions of youth provided by the African Youth Charter and Ghana’s National Youth Policy, farm households were categorized into three age-based groups: youth (15–35 years), middle-aged (36–59 years) and aged (60 years and above). The findings indicate that farm operator age does not have a statistically significant effect on the type or level of agricultural technology adopted by farming households in Ghana. This finding remains robust even when the analysis is disaggregated by cereal type (i.e., maize, rice, millet and sorghum). However, the findings reveal marked differences in managerial performance between younger and older farmers, with the youth exhibiting greater managerial proficiency relative to their older peers. These findings suggest that when offered equal access to productive resources, younger farmers are better equipped to drive agricultural productivity growth in Ghana, thereby significantly contributing to the sector’s growth in the country. The study recommends for policymakers to pursue youth-focused agrarian initiatives that ensure easy access of the youth to productive resources such as land, credit and improved technologies, aimed at enabling younger farmers to leverage their potential in driving agricultural productivity gains.
Overall, the findings of this thesis bring to the fore the existing systemic barriers that continue to obstruct smallholder investment decisions in sustainable land use practices like ISFM in land-abundant contexts like Mozambique and further underscore the urgent need for policy measures aimed at addressing them. It further stresses that the greatest potential for sustainably raising farm performance in low-input food crop systems in Mozambique lies in the ability of resource-poor farmers to implement these low-cost agronomic practices more efficiently. Finally, the findings highlight the need to focus on enhancing the managerial skillsets of farm operators across all age groups, especially the younger ones, rather than just concentrating on technological advancements.Die Steigerung der Produktivität der Landwirtschaft in Subsahara-Afrika (SSA) ist von grundlegender Bedeutung für die Erreichung vieler der Ziele für nachhaltige Entwicklung (SDGs) in der Region und darüber hinaus in der ganzen Welt. Angesichts ihrer Bedeutung für das Leben auf dem Land, den Lebensunterhalt und die Volkswirtschaften in SSA hat die Produktivitätssteigerung in diesem wichtigen Sektor das Potenzial, eine breit angelegte Armutsbekämpfung (SDG 1) anzuregen und die anhaltenden Probleme der Ernährungsunsicherheit und Unterernährung (SDG 2) in der Region weiter anzugehen. Trotz ihres Wachstumspotenzials und ihrer Bedeutung für die Region hat das Produktivitätswachstum in der Landwirtschaft in SSA im Laufe der Jahre stagniert oder ist zurückgegangen. Die Bemühungen zur Bewältigung dieser anhaltenden Herausforderung konzentrierten sich auf die Förderung verbesserter Technologiepakete und moderner Anbaumethoden. Dennoch blieb die Akzeptanz in SSA zumeist schleppend. Dies unterstreicht die Notwendigkeit, die zugrunde liegenden Barrieren für eine nachhaltige Adoption tiefer zu verstehen. Zudem bedarf es einer genauen Analyse der Auswirkungen adoptierter Technologien und Praktiken auf die Betriebsleistung, insbesondere hinsichtlich der technischen Effizienz und technologischer Gewinne.
Die kleinbäuerlichen Kontexte in Mosambik und Ghana eignen sich besonders gut, um nützliche Einblicke in die zugrunde liegenden Hindernisse für die nachhaltige Einführung moderner Technologien und landwirtschaftlicher Praktiken zu gewinnen. Gleichzeitig ermöglichen sie das Verständnis ihrer Auswirkungen auf die landwirtschaftliche Leistung. Trotz der laufenden Bemühungen der mosambikanischen Regierung und der Entwicklungspartner um die Förderung nachhaltiger Intensivierungspraktiken, wie z. B. des integrierten Bodenfruchtbarkeitsmanagements (BFM - einschließlich Mineraldünger, verbessertem Saatgut und je nach Standort auch organischen Inputs wie Dung und Kompost), ist die Akzeptanz in den landwirtschaftlichen Haushalten nach wie vor gering. Infolgedessen greifen ressourcenarme Landwirte häufig auf nicht nachhaltige Landnutzungspraktiken wie Wanderfeldbau, Brandrodung, Entwaldung und Waldschädigung zurück, und zwar zusammen mit kostengünstigen agronomischen Praktiken wie Fruchtfolge, Rückhaltung von Ernterückständen und Zwischenfruchtanbau, um die Bodenfruchtbarkeit zu erhalten. Es gibt jedoch kaum Erkenntnisse über die Hindernisse, die einer nachhaltigen Übernahme der geförderten ISFM-Praktiken im Wege stehen, sowie über die technologischen und technischen Effizienzgewinne, die mit der Integration von verbessertem Saatgut im Vergleich zu Recycling-Saatgut und agronomischen Praktiken in Mosambik verbunden sind.
Eine der größten Herausforderungen für die Einführung von Technologien, die Leistungsfähigkeit der Betriebe und die langfristige Nachhaltigkeit der Landwirtschaft ist die Überalterung der landwirtschaftlichen Bevölkerung. Dieses Problem ist in Ghana besonders dringlich, denn neben dem wachsenden Desinteresse junger Menschen an der Landwirtschaft und einer geschätzten Lebenserwartung von 55 bis 65 Jahren liegt das Durchschnittsalter der Landwirte bei 55 Jahren. In Anbetracht der Tatsache, dass die Mehrheit (73,5 %) der ghanaischen Bevölkerung unter 36 Jahre alt ist, ist ein besseres Verständnis darüber, wie das Alter der Landwirte ihre Managementleistung und Technologieübernahme beeinflusst, von entscheidender Bedeutung für die Gestaltung einer faktengestützten Politik, die darauf abzielt, diese demografische Dividende im ghanaischen Agrarsektor zu gewinnen, zu halten und zu nutzen. Ausgehend davon verfolgt diese Arbeit drei Hauptziele: (1) Erforschung kontextspezifischer systemischer Hindernisse für die nachhaltige Einführung von integriertem Bodenfruchtbarkeitsmanagements (BFM) durch mosambikanische Kleinbauern; (2) Untersuchung der technologischen und technischen Effizienzgewinne, die mit der Integration von verbessertem bzw. recyceltem Saatgut und agronomischen Praktiken wie Fruchtfolge, Zwischenfruchtanbau und Rückstandsmanagement durch mosambikanische Kleinbauern verbunden sind; und (3) Bewertung, wie das Alter der Landwirte - unterteilt in junge, mittelalte und alte Menschen - ihre Managementleistung und die Technologieadoption im Agrarbereich in Ghana beeinflusst.
Die Ziele dieser Arbeit wurden durch eine Kombination aus Primär- und Sekundärdaten erreicht. Ein Mixed-Methods-Forschungsdesign ermöglichte die Erhebung qualitativer Daten mittels Schlüsselinformanten-Interviews (KIIs) und Fokusgruppendiskussionen (FGDs), ergänzt durch quantitative Daten aus einer Haushaltsbefragung in den zentralen und nördlichen Regionen Mosambiks. Diese Primärdaten dienten der Bearbeitung der ersten beiden Forschungsziele. Insgesamt wurden 32 qualitative Interviews, bestehend aus 8 FGDs, 5 KIIs mit mittleren und großen Landwirten und 19 KIIs mit Experten, in Mosambik durchgeführt. Im Anschluss daran wurde eine Haushaltsbefragung in den zentralen und nördlichen Zonen Mosambiks durchgeführt, an der 607 Bauernhaushalte teilnahmen, die durch ein mehrstufiges Stichprobenverfahren ausgewählt wurden. Beide Datensätze wurden im Jahr 2022 erhoben. Um das dritte Forschungsziel der Arbeit zu untersuchen, wurden Sekundärdaten aus zwei landesweit repräsentativen Erhebungen in Ghana herangezogen. Dazu gehören alle sieben Wellen des Ghana Living Standards Survey (GLSS), die von 1987/88 bis 2016/17 durchgeführt wurden, und die beiden Wellen des Ghana Socio-economic Panel Survey (GSPS), die zwischen 2009/10 und 2014/15 durchgeführt wurden. Während die GLSS als wiederholte Querschnittsstudie konzipiert war, folgte die GSPS einem Paneldesign. Insgesamt wurden 24.596 landwirtschaftliche Haushalte in ganz Ghana in die Stichprobe für die Analyse einbezogen.
Die vorliegende Arbeit ist in fünf Kapitel gegliedert. Kapitel 1 führt in das Forschungsthema ein, indem es einen allgemeinen Überblick über die Studie im globalen und subsaharischen Kontext gibt, gefolgt von Hintergrundinformationen zur Landwirtschaft und Technologieübernahme in Mosambik und Ghana. Kapitel 2 untersucht die systemischen Barrieren, die die nachhaltige Einführung von BFM-Praktiken unter mosambikanischen Kleinbauern behindern. Kapitel 3 bewertet die technologischen und technischen Effizienzgewinne, die mit den bestehenden Praktiken der Landwirte bei der Integration von verbessertem bzw. recyceltem Saatgut mit agronomischen Praktiken in Mosambik verbunden sind. In Kapitel 4 wird der Zusammenhang zwischen dem Alter der Landwirte, der Technologieanwendung und der Managementleistung in Ghana untersucht. Schließlich werden in Kapitel 5 die Schlussfolgerungen dieser Arbeit vorgestellt, ihre Grenzen aufgezeigt und Empfehlungen für die Politik und künftige Studien gegeben.
Kapitel 2 nutzt ein Mixed-Methods-Forschungsdesign. Es untersucht systemische Hindernisse für die nachhaltige Einführung von BFM-Praktiken bei ressourcenarmen Bauern in Mosambik. Die Ergebnisse einer Inhaltsanalyse qualitativer Daten und einer deskriptiven Haushaltsbefragung zeigen: Mosambikanische Kleinbauern erkennen die Notwendigkeit von BFM-Praktiken in hochwertigen Anbausystemen (wie Gemüse, Baumwolle, Zuckerrohr und Tabak). Jedoch zögern sie, ähnliche Investitionen in Nahrungspflanzen zu tätigen. Stattdessen greifen die Landwirte auf kostengünstige Praktiken zurück, um die Bodenfruchtbarkeit in Nahrungspflanzensystemen zu sichern. Dazu zählen die Bewirtschaftung von Ernterückständen, Zwischenfruchtanbau, Fruchtfolge sowie der Wanderfeldbau. Darüber hinaus wird deutlich, dass die Anwendung von verbessertem Saatgut, Mineraldünger und – standortabhängig – externen organischen Inputs wie Mist und Kompost bei drei spezifischen Gruppen mosambikanischer Kleinbauern eine höhere Verbreitung findet: bei unabhängigen Gemüseproduzenten, bei Landwirten, die an Vertragsanbausystemen teilnehmen, und bei denjenigen, die in an und Malawi, Sambia und Simbabwe grenzenden Distrikten ansässig sind leben. Obwohl die Landwirte eine hohe Investitionsbereitschaft in diese Betriebsmittel zeigen, wird ihr Zugang und deren Nutzung durch eine Reihe komplexer systemischer Hindernisse erschwert. Dazu zählen ungünstige Marktbedingungen, welche die Rentabilität einschränken
Detection of HHV-5 HHV-6a HHV-6b and HHV-7 in the urine: potential use as a non-invasive diagnostic tool for immune profiling
No full textDecline in immune function with age has been studied extensively, but approaches to immune restoration have been hampered by the lack of simple methods of identifying individuals whose immune system is in decline. Our approach has been to identify individuals whose immune decline has led to a loss of control of common latent viral infections and their consequent reactivation. Viruses excreted in urine were detected and quantified and we believe this approach could provide a 'surrogate marker' for identifying immune compromised individuals. Here we report the detection of human herpes virus (HHV) 5, 6a, 6b and 7 in the urine of healthy individuals over a wide age range and their correlation with T cell receptor excision circle (TREC) data. The results did not show a clear correlation between TREC values and the detection of individual specific viruses or viral load values when measured singly. However, a correlation was found between low TREC values and the detection of several different human herpes viruses in the urine in males. We present evidence suggesting that for males, the detection of three or more different human herpes viruses in the urine could identify individuals with declining immune function as evidenced by their significantly lower TREC levels
Genome-wide association study for in vitro digestibility and related traits in triticale forage
No full textBackground: Triticale is making its way on dairy farms as an alternative forage crop. This requires the availability of high-yielding triticale varieties with good digestibility. Triticale forage breeding mainly focussed on biomass yield, but efforts to improve digestibility are increasing. We previously investigated the interrelationships among different quality traits in soft dough triticale: starch, acid detergent fibre and in vitro digestibility of organic matter (IVOMD) and of neutral detergent fibre (IVNDFD) of the total plant, IVNDFD and Klason lignin of the stems, and ear proportion and stem length. Here we determine the genetic control of these traits, using a genome-wide association (GWAS) approach. A total of 33,231 DArTseq SNP markers assessed in a collection of 118 winter triticale genotypes, including 101 varieties and 17 breeding lines, were used. Results: The GWAS identified a total of 53 significant marker-trait associations (MTAs). The highest number of significantly associated SNP markers (n = 10) was identified for total plant IVNDFD. A SNP marker on chromosome 1A (4211801_19_C/T; 474,437,796 bp) was found to be significantly associated with ear proportion, and plant and stem IVNDFD, with the largest phenotypic variation for ear proportion (R²p = 0.23). Based on MTAs, candidate genes were identified which were of particular relevance for variation in in vitro digestibility (IVD) because they are putatively involved in plasma membrane transport, cytoskeleton organisation, carbohydrate metabolic processes, protein phosphorylation, and sterol and cell wall biogenesis. Interestingly, a xyloglucan-related candidate gene on chromosome 2R, SECCE2Rv1G0126340, was located in close proximity of a SNP significantly associated with stem IVNDFD. Furthermore, quantitative trait loci previously reported in wheat co-localized with significantly associated SNP markers in triticale. Conclusions: A collection of 118 winter triticale genotypes combined with DArTseq SNP markers served as a source for identifying 53 MTAs and several candidate genes for forage IVD and related traits through a GWAS approach. Taken together, the results of this study demonstrate that the genetic diversity available in this collection can be further exploited for research and breeding purposes to improve the IVD of triticale forage.Fachagentur Nachwachsende Rohstoffehttp://dx.doi.org/10.13039/501100010812Horizon 2020http://dx.doi.org/10.13039/50110000760
Effect of smoldering air volume flow rates and smoking time on quality attributes of Frankfurter-type sausages
Full text linkThis study explores the effects of varying smoking conditions on the properties of Frankfurter-type sausages. Using a modified smoldering smoke generator, air volume flow rate and smoking time were varied to assess their impact on color, texture, and sensory characteristics. The results showed significant changes in these characteristics and a wide spectrum in smoke color was produced across the 14 different settings. L* values ranged from 64.32 ± 0.61 to 46.33 ± 0.78, a* values ranged from 11.81 ± 0.29 to 24.18 ± 0.39, b* values ranged from 14.93 ± 0.77 to 41.20 ± 1.25 with an increase in smoking time and air volume flow generally leading to a darker smoking color. Sensory test regarding color showed that the perceived color behaved similarly to the measured color. In these descriptive tests the perceived color ranged from 0.42 ± 0.42 to 9.67 ± 0.43 on a scale from 0 to 10. Smoke odor did not show the strong differences seen in the other results. Here the perceived smoke odor ranged from 4.76 ± 2.00 to 8.64 ± 1.03 on a scale from 0 to 10. Since the study was based on a statistical experimental plan, a predictive model based on a surface plot could be established. These findings provide valuable insights in the qualitative changes in Frankfurter -Type sausages for optimizing smoking parameters in the food industry, potentially enabling precise control over desired sensory and physical properties in smoked meat products.Open Access funding enabled and organized by Projekt DEAL.Universität Hohenheim (3153
Role of homovanillic acid esters in the regulation of skin inflammatory pathways and their effect on tight junction protein expression
Full text linkIn the context of epidermal inflammation, the inflammatory response not only involves the release of inflammatory cytokines like interleukin 8 (IL-8), but also modulation of tight junction protein expression levels. Previous studies showed that the tight junction protein claudin 1 (CLDN1) is upregulated during tumor necrosis factor α (TNFα)-induced inflammation by capsaicin in keratinocytes in a transient receptor potential channel vanilloid 1 (TRPV1)-dependent manner. However, the caveat with TRPV1 ligands is the undesired pain response elicited by the activation of neuronal TRPV1 channels. In this study, we hypothesized that also less or non-pungent homovanillic acid esters as structural analogs of capsaicin target CLDN1 upregulation during inflammation. Methods: We aimed to identify beneficial structural characteristics by selecting homovanillic acid esters with different aliphatic tail structures and screening them for CLDN1 upregulation at early stages of TNFα-induced inflammation in basal keratinocytes. Results: CLDN1 expression was upregulated independently of TRPV1 by compounds with a tail of 5 or 6 C-atoms, regardless of the presence of ramifications and double bonds with a maximum fold change of 2.05 ± 0.22 against control. The induction of CLDN1 expression was accompanied by increased expression of the differentiation marker involucrin (IVL). Discussion: The results suggest that the homovanillic ester-induced CLDN1 upregulation is a result of increased differentiation of the basal keratinocytes towards the keratinocyte morphology present in the stratum granulosum (SG), where tight junctions are formed. In conclusion, homovanillic acid esters with a 5 or 6 C-atom long aliphatic chain induced CLDN1 expression, thereby stimulating keratinocyte differentiation, independent from TRPV1 activation
Hydration-induced reduction strategies of acrylamide in bakery products
Full text linkBread is a product made from cereals and/or cereal-based ingredients, which are combined with water or other water-containing liquids. Also, additional ingredients such as oilseeds, legumes, potato products, dairy products, spices, and vegetables may be incorporated into the dough. Products containing these ingredients can be referred to as special bakery products. However, the use of these additional ingredients has been raising food-safety concerns, particularly because of the possibly elevated levels of acrylamide detected in the final products. Acrylamide is a process contaminant, considered undesirable due to its potential carcinogenicity and is currently subject to various European food safety regulations. However, the acrylamide mitigation strategies defined so far for standard bakery products do not appear to be sufficiently effective for special bakery products. This is presumably due to the high levels of precursor molecules and the varying quality of the special ingredients. As a result, there are large variations in the levels of precursors, namely reducing sugars and asparagine in the dough, which consequently lead to unpredictably elevated acrylamide contamination. To address these problems and to gain a deeper understanding of acrylamide formation in special bakery products, further investigation is essential. Therefore, this thesis aimed to identify specific acrylamide precursors, to analyze acrylamide levels, and to assess the effectiveness of hydration-based approaches as mitigation measures for special bakery products. Mitigation was to be achieved either by eliminating the precursors or by adjusting processing conditions.
After a theoretical introduction in Chapter I, a systematic investigation of two special ingredients, with a focus on their specific acrylamide precursors, was presented in Chapter II and Chapter III. Particular attention was drawn to potato flakes, known for their high asparagine content, and carrot strips, awaited to be high in reducing sugars. The effects of these ingredients in combination with varying water additions as hydration approach, were investigated using a model dough recipe. The model dough consisted of wheat flour type 550, water, NaCl, yeast and selected special ingredients. After baking, both bread crust and crumb were analyzed for acrylamide and in parallel, baking qualities of these bakery products were evaluated. Considering acrylamide contamination, increased water addition showed highly raw material-specific effects. In high-asparagine doughs, higher dough water addition tended even to increase acrylamide formation, presumably due to enhanced mobility of precursors. Interestingly, for the carrot-based doughs, the polyphenols emerged as a potential factor significantly reducing acrylamide formation at higher water additions, highlighting their relevance for future mitigation strategies.
Due to the significant differences in the qualities of available carrot strips, shown in Chapter III, Chapter IV described the effects of origin, processing and drying methods on different quality features of dried carrot strips. For that, three carrot varieties were purchased and processed. Processing steps included blanching and drying methods, such as hot-air drying, vacuum drying, or freeze-drying. The impact of each processing method on quality of carrot strips, their acrylamide-forming potential, and the resulting acrylamide levels in model bakery products was analyzed. Blanching in particular, significantly reduced the acrylamide formation potential of the carrot strips. Freeze-drying consistently resulted in the highest concentrations of sugars, free asparagine, and β‑carotene for all carrot varieties, whereas the retainment of these compounds was inconsistent with other drying methods. Asparagine levels during storage were shown to fluctuate, with an initial increase and a following decrease, underlining the importance of timed processing to warrant constant product quality. Overall, the potential of carrot strips for acrylamide formation depended mostly on their variety and storage conditions, which determined primarily their precursor profile.
To investigate a variety-unspecific acrylamide mitigation strategy, soaking was evaluated in Chapter V as an approach for products with dried carrot strips. Additionally, ultrasound-assisted rehydration was investigated as a method to enhance the diffusion of carrot matrix constituents. Regular soaking was compared with ultrasound-assisted rehydration (ultrasonic bath or sonotrode) regarding rehydration rate and leaching of sugars from the carrot strips. The kinetics of rehydration and diffusion were modelled using the ExpAssoc and the Peleg equations. Rehydrated carrot strips were then implemented in model breads and acrylamide concentration in the crust along with baking qualities were analyzed. Overall, longer rehydration led to higher water retention in the carrot strips and increased leaching of sugars and polyphenols. Both ultrasound-assisted rehydration and regular soaking led to reduced acrylamide levels in model breads up to 75%.
Summarizing, this thesis systematically examined the addition of potato flakes and carrot strips to bakery products, identifying their critical acrylamide precursors, expected acrylamide levels, and characteristic changes in bread quality. It proved that rehydration is an effective acrylamide mitigation strategy for special bakery products, primarily by promoting precursor leaching and influencing reaction conditions. Overall, this thesis provides guidance on the target raw material qualities and presents (easy-to-apply) mitigation approaches for various manufacturers.Brot ist ein Lebensmittel aus Getreide und/oder getreidebasierten Zutaten, die mit Wasser oder anderen Flüssigkeiten kombiniert werden. Auch weitere Zutaten, wie Ölsaaten, Hülsenfrüchte, Kartoffelprodukte, Milchprodukte, Gewürze und Gemüse können in den Teig eingearbeitet werden. Diese daraus entstehenden Backwaren werden als Spezialbackwaren bezeichnet. Die Verwendung dieser Zutaten wirft jedoch etwaige Bedenken hinsichtlich der Lebensmittelsicherheit auf, insbesondere aufgrund der möglicherweise erhöhten Acrylamidgehalte in den Endprodukten. Acrylamid ist eine Prozesskontaminante, die aufgrund ihrer potenziellen kanzerogenen Wirkung unerwünscht ist und aus diesem Grund heutzutage europäischen lebensmittelrechtlichen Regelungen unterliegt. Allerdings sind die bislang für Standardbackwaren definierten Maßnahmen zur Acrylamidminimierung bei Spezialbackwaren nicht hinreichend wirksam. Dies ist vermutlich auf den hohen Anteil an Acrylamidvorstufen, wie reduzierende Zucker und die Aminosäure Asparagin, als auch auf die schwankende Qualität der Spezialzutaten zurückzuführen. Infolgedessen sind große Unterschiede in den Konzentrationen an Acrylamidvorstufen in den Spezialzutaten zu verzeichnen, was wiederum zu unvorhersehbar erhöhten Acrylamidgehalten in den Spezialbackwaren führt. Um diese Problematik zu adressieren und ein grundlegendes Verständnis der Acrylamidbildung in Spezialbackwaren zu gewinnen, sind weitere Untersuchungen somit unerlässlich. Demnach war das Ziel dieser Arbeit, spezifische Acrylamidvorstufen zu identifizieren, Acrylamidgehalte zu analysieren und die Wirksamkeit hydratationsbasierter Ansätze als Minimierungsmaßnahmen für Spezialbackwaren zu untersuchen. Die Minimierung sollte dabei entweder durch Eliminierung der relevanten Vorstufen oder durch Anpassung der Verarbeitungsschritte erreicht werden. Nach einer theoretischen Einführung in Chapter I wurde in Chapter II und Chapter III eine systematische Untersuchung zweier Spezialzutaten präsentiert, mit dem Fokus auf deren spezifischen Acrylamidvorstufen. Ausgewählt wurden Kartoffelflocken, die für ihren hohen Asparagingehalt bekannt sind, sowie Karottenstreifen, bei denen ein hoher Gehalt an reduzierenden Zuckern erwartet wurde. Die Auswirkung dieser Spezialzutaten, in Kombination mit variierenden Wasserzugaben zum Teig als Hydratationsansatz, wurden danach anhand einer Modellteigrezeptur untersucht. Für den Modellteig wurden Weizenmehl Type 550, Wasser, NaCl, Hefe und die jeweiligen Spezialzutaten verwendet. Nach dem Backen wurden Kruste und Krume auf Acrylamid untersucht und parallel dazu die Backqualität dieser Produkte analysiert. Die Acrylamidkontamination hat bei erhöhter Wasserzugabe stark rohstoffspezifische Effekte gezeigt. In asparaginreichen Teigen wurde eine Erhöhung der Acrylamidgehalte beobachtet, vermutlich aufgrund einer verstärkten Mobilität der Vorstufen. Interessanterweise zeigte sich bei den Karottenstreifen, dass der Polyphenolgehalt der Spezialzutaten eine wichtige Rolle bei der Verringerung der Acrylamidbildung mit erhöhter Wasserzugabe spielte. Dies verdeutlichte somit die Relevanz der Polyphenole für zukünftige Minimierungsmaßnahmen.
Aufgrund der in Chapter III, festgestellten signifikanten Qualitätsunterschiede in den untersuchten Karottenstreifen, wurde in Chapter IV der Einfluss von Herkunft, Verarbeitung und Trocknungsmethoden auf verschiedene Qualitätsmerkmale getrockneter Karottenstreifen untersucht. Hierfür wurden drei Karottensorten bezogen und verarbeitet. Die Verarbeitungsschritte umfassten Blanchieren und Trocknungsmethoden wie die Heißlufttrocknung, Vakuumtrocknung oder Gefriertrocknung. Dabei wurden der Einfluss der Verarbeitungsschritte auf die Qualität der Karottenstreifen, ihr Acrylamidbildungspotenzial sowie die resultierenden Acrylamidgehalte in Modellbackwaren untersucht. Insbesondere das Blanchieren reduzierte das Acrylamidbildungspotenzial der Karottenstreifen signifikant. Die Gefriertrocknung führte bei allen Karottensorten zu den höchsten Gehalten an Zuckern, freiem Asparagin und β-Carotin. Hinsichtlich der Retention dieser Verbindungen zeigten die restlichen Trocknungsmethoden allerdings uneinheitliche Ergebnisse. Die Asparagingehalte schwankten bereits während der Lagerung, mit einem anfänglichen Anstieg und anschließendem Rückgang, was die Bedeutung einer zeitgerechten Verarbeitung zur Sicherung einer konstanten Produktqualität unterstreicht. Insgesamt war das Acrylamidbildungspotenzial der Karottenstreifen vor allem von der Sorte und den Lagerungsbedingungen abhängig, da diese maßgeblich das Acrylamid-Vorstufenprofil beeinflusst haben.
Um sortenunabhängige Minimierungsmaßnahmen von Acrylamid zu erforschen, wurde in Chapter V das Einweichen als Ansatz für Produkte mit getrockneten Karottenstreifen untersucht. Darüber hinaus wurde die ultraschallunterstützte Rehydratation als Methode zur Förderung der Diffusion von Inhaltsstoffen aus dem Karottengewebe betrachtet. Insgesamt wurde die Rehydratation durch herkömmliches Einweichen mit der ultraschallunterstützten Rehydratation (Ultraschallbad oder Sonotrode) hinsichtlich der Rehydratationsrate und des Auswaschens von Zuckern aus den Karottenstreifen verglichen. Die Kinetik der Rehydratation und Diffusion wurde mithilfe der ExpAssoc- und Peleg-Gleichungen modelliert. Rehydratisierte Karottenstreifen wurden anschließend in Modellbrote eingearbeitet. Abschließend wurden die Acrylamidkonzentrationen in den Krusten sowie verschiedene Faktoren der Gebäckqualität analysiert. Insgesamt führte eine längere Rehydratation zu einem höheren Wassergehalt in den Karottenstreifen und zu einem verstärkten Auswaschen von Zuckern und Polyphenolen. Sowohl ultraschallunterstützte Rehydratation als auch herkömmliches Einweichen führten zu einer Reduktion der Acrylamidgehalte in Modellbroten von bis zu 75%.
Zusammenfassend beschäftigte sich diese Arbeit mit der systematischen Analyse der Zugabe von Kartoffelflocken und Karottenstreifen zu Backwaren, der Identifizierung kritischer Acrylamidvorstufen und erwarteter Acrylamidgehalte sowie der charakteristischen Veränderungen in der Brotqualität dieser Spezialbackwaren. Es konnte gezeigt werden, dass die Rehydratation eine wirksame Strategie zur Acrylamidminimierung darstellt, vor allem durch die Förderung des Auswaschens von Acrylamidvorstufen und die Beeinflussung der Reaktionsbedingungen. Insgesamt bietet diese Arbeit eine Übersicht hinsichtlich der erforderlichen Rohstoffqualitäten und präsentiert (einfach) umsetzbare Strategien zur Minimierung von Acrylamid für verschiedene Hersteller
Guidelines for improved quantification and reporting of carbon stocks and additional carbon storage in agroforestry systems
Full text linkThe number of scientific publications related to biomass carbon or soil organic carbon under various land management practices has globally and dramatically increased during the last two decades, the same applies to the peer reviewed Agroforestry Systems journal. However, the quality of papers on carbon sequestration in agroforestry systems is very heterogeneous, and many studies do not fulfil simple requirements that would ensure the scientific value of these studies, resulting in high rates of rejections before and after review. The aim of this paper, co-authored by the Editor-in-Chief and Associate Editors of the Agroforestry Systems journal is to provide some basic guidelines to improve the quantification and reporting of carbon stocks and additional carbon storage in agroforestry systems, and to maximize manuscript acceptance. These guidelines are also of use for any other international peer-reviewed journal publishing studies on this topic. We also provide a checklist, for both authors and reviewers, of compulsory and recommended variables to be included before submission of an original study related to soil and/or biomass carbon stocks and sequestration in agroforestry systems.Open access funding provided by CIRAD.CIRA
Interactions between lipid oxidation and anthocyanins from black carrots in ω-3 fatty acid-rich flaxseed oil-in-water emulsions
Full text linkThe application of anthocyanins as red colorants in lipid-containing foods such as oil-in-water emulsions is challenging due to their ability to act as antioxidants and their instability under various environmental conditions. In this study, we investigated the kinetics of black carrot anthocyanin degradation and the subsequent color loss influenced by lipid oxidation reactions in 1% ( w/w ) flaxseed oil-in-water emulsions stabilized by 0.1% ( w/w ) sodium dodecyl sulfate (SDS) at pH 2 upon storage at 35 °C for ten days under light and in the dark. Oxidatively stable Miglyol oil-in-water emulsions and SDS solutions were used as reference. The results showed simultaneous formation of lipid hydroperoxides and degradation of anthocyanins. The addition of anthocyanins decreased lipid hydroperoxide formation, confirming the antioxidant activity of anthocyanins through radical scavenging mechanism. The kinetic modelling of lipid oxidation and anthocyanin degradation are particularly important for estimating color stability in colored emulsion-based food systems such as dairy or non-dairy milk or yoghurt drinks.Open Access funding enabled and organized by Projekt DEAL.Universität Hohenheim (3153