Newest publications
Aqueous Kabachnik -Fields synthesis of HMF-functionalized chitosan for thermally-stable LBL coatings on cotton fabrics
(2026) Checa, M.; Arauzo, P.J.; Kruse, A.
This study explores the Kabachnik-Fields (KF) reaction between chitosan, diethyl phosphite (DEP) and biorefinery-derived 5-hydroxymethylfurfural (HMF) to produce chitosan-diethyl phosphite-HMF (CDH) derivatives for thermally-stable coatings. The effect of reaction temperature on the structure, phosphorus incorporation and thermal properties of the CDH-RT (room temperature), CDH-60 (60 °C), CDH-80 (80 °C) and CDH-100 (100 °C) products was investigated using FTIR, elemental analysis, ICPOES and thermogravimetric analysis (TGA) in air. KF modification increased chitosan's initial thermal stability (T₅: 65 to 84-104 °C), promoted early char formation through an intumescent mechanism and enhanced residue stability at 930 °C (max. 32.4 wt %). To assess LBL coating compatibility, CDH products were applied to cotton fabrics (3 bilayers with phytic acid). Mass gain depended on KF temperature, with cotton-CDH-60/PA showing optimal incorporation (34.4 %). Synergy factors calculated from normalized TGA residues confirmed positive char-promoting effects for all CDH formulations (cotton-CDH-60/PA: 226.6 %). These results establish HMF-chitosan aminophosphonates as a promising platform for sustainable, thermally-protective cotton fabric coatings.
Maternal differences for the reaction to ergot in unfertilized hybrid rye (Secale cereale)
(2022) Kodisch, Anna; Schmiedchen, Brigitta; Eifler, Jakob; Gordillo, Andres; Siekmann, Dörthe; Fromme, Franz Joachim; Oberforster, Michael; Miedaner, Thomas
Claviceps purpurea causing ergot maintains to be a problem in commercial cytoplasmic male sterile (CMS)-based hybrid rye growing. The fungal spores compete with pollen during flowering and ergot incidence is reduced in highly pollen-shedding stands. This study was carried out to identify maternal differences in ergot infection in the absence of pollen. Ten male-sterile single crosses were tested by needle and spray inoculation and kept unfertilized in up to four field sites (Germany, Austria) and three greenhouse experiments, respectively, in two years. A medium to high correlation was observed between field (needle inoculation) and greenhouse (spray inoculation) experiments. The environments (=location × year combinations) differed in their ergot severity and ergot incidence. Significant ( P ≤ 0.05) genotypic and genotype × environment interaction variances were detected for the unfertilized male-sterile single crosses in both test systems for both traits. The single cross K_4 showed a significantly lower ergot severity averaged across all environments, thus being more resilient to ergot than the other genotypes. In conclusion, spray and needle inoculation are suitable for testing unfertilized male-sterile rye materials, testing across several environments (locations, years) is definitely necessary. Selection of specific females might give the potential for further reducing ergot contamination in hybrid rye in future. The frequency of such genotypes within larger breeding populations needs to be analyzed.
Influence of wet extrudates from pumpkin seed proteins on drying, texture, and appearance of dry-cured hybrid sausages
(2022) Ebert, Sandra; Jungblut, Florence; Herrmann, Kurt; Maier, Barbara; Terjung, Nino; Gibis, Monika; Weiss, Jochen
Hybrid meat products represent a promising, more sustainable alternative to all-meat formulations. However, differences among plant- and animal-based proteins may alter traditional handling and final product properties. In this study, pork meat was partially replaced with texturized pumpkin seed proteins at 12.5, 25, 37.5, and 50% to obtain dry-cured hybrid meat sausages and their ripening (acidification, drying) during 21 days and final product properties (texture, sensory) were characterized and compared to a control (all-meat formulation). The drying behavior and distribution of moisture and free water of hybrids with extrudate contents of 12.5 and 25% were comparable to the sample made with meat and no significant ( p > 0.05) differences in proximate composition were found. In contrast, higher meat replacement levels resulted in distinct changes of compositional and textural attributes i.e. chewiness was decreasing by up to 70%. Results suggested 25% of extrudates as an important threshold in manufacture of hybrid dry-cured sausages due to alterations in their ability to bind or release water. Results may be used to understand the influence of alternative texturized proteins in hybrid formulations and help product developers to understand related process and product relevant changes.
Quantification of tocochromanols in vitamin E dietary supplements by instrumental thin-layer chromatography
(2022) Kröpfl, Alexander; Schweizer, Sina; Vetter, Walter
A variety of vitamin E dietary supplement capsules (DSC) based on different natural oils or synthesis products are currently found on the market whose vitamin contents need to be controlled before and after marketing. Here, we present an instrumental thin-layer chromatography (TLC) method which allows a direct determination of all tocopherols (T) and tocotrienols (T3) as well as α-tocopherol acetate simultaneously in one run with short analysis time. For this purpose, contents of the DSC were extracted, applied on silica gel 60 plates, and developed with n-hexane/ethyl acetate/acetic acid, 90:10:2 (v/v/v) as mobile phase. The UV scan of the plate at 293 nm was used for quantification based on the peak height. Following the scan, the plate was treated with 10% sulphuric acid in methanol which led to characteristic yellow-to-brown colouring of the tocochromanol spots which allowed to distinguish tocochromanols from matrix components with similar Rf values. In most cases, determined vitamin E contents matched well with the information listed on the label of the investigated DSC samples. The method is fast, easy to perform and gently treats the analytes as it requires no thermal treatment prior to quantification, which makes it suitable as a screening method.
Benchmarking of secure group communication schemes with focus on IoT
(2024) Prantl, Thomas; Bauer, André; Engel, Simon; Horn, Lukas; Krupitzer, Christian; Iffländer, Lukas; Kounev, Samuel
As 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.