Institut für Lebensmittelwissenschaft und Biotechnologie

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Almond-like aroma formation of acid whey by Ischnoderma benzoinum fermentation: potential application in novel beverage development
(2025) Hannemann, Lea; Klauss, Raphaela; Gleissle, Anne; Heinrich, Patrick; Braunbeck, Thomas; Zhang, Yanyan
To address the sourish off-aroma of acid whey and enhance its upcycling, a new basidiomycete Ischnoderma benzoinum -mediated fermentation system was developed using pure acid whey as the sole substrate. A pleasant sweetish and marzipan-like odor was perceived after fermentation within 7 d at 24 °C in darkness, which was shaped from key contributors including 4-methoxybenzaldehyde (odor activity value (OAV) 878), 3-methylbutanal (OAV 511), 3,4-dimethoxybenzaldehyde (OAV 50), and benzaldehyde (OAV 28). The typical sweetish and almond-like odor persisted well after ultrahigh-temperature processing, though its intensity decreased slightly. Concurrently, the fermentation reduced lactose from 52 to 20 g/L but increased the contents of essential amino acids like threonine, leucine, and lysine. No significant cytotoxicity or genotoxicity differences were found between fermented and unfermented whey. Overall, the study highlights the capability of I. benzoinum fermentation to enhance the flavor of acid whey, offering a promising approach for creating nutritional and flavorful acid-whey-based products.
Application of AprX from Pseudomonas paralactis for the improvement of the emulsifying properties of milk, plant and insect protein and estimation of their hydrolysate’s bitter potential
(2025) Volk, Veronika; Ewert, Jacob; Longhi, Miriam; Stressler, Timo; Fischer, Lutz
Protein properties can be modified by selective enzymatic hydrolysis. In this study, the alkaline metalloendopeptidase AprX (Serralysin; EC 3.4.24.40) from Pseudomonas paralactis was used for the tailored hydrolysis of different food proteins resulting in the production of protein hydrolysates with improved emulsifying properties. Sodium caseinate, wheat gluten and buffalo worm protein were used for AprX hydrolysis at 40 °C and pH 8 to cover a spectrum of different protein sources. A maximum degree of hydrolysis (DH) of 13.1 ± 0.2%, 14.2 ± 0.1% and 20.7 ± 0.1% was reached for sodium caseinate, wheat gluten and the worm protein, respectively. The corresponding hydrolysate properties were analyzed regarding their particle size, peptide composition, solubility, viscosity, surface hydrophobicity and interfacial tension. The emulsifying properties were investigated by the oil-droplet size, ζ-potential and stability of emulsions prepared from the hydrolysates. Using partially hydrolyzed sodium caseinate (DH = 10.6%) as an emulsifier lead to an eightfold increase of the emulsion stability (t1/2 = 180 ± 0 min) compared to unhydrolyzed sodium caseinate. The emulsion stability using wheat gluten hydrolysates (DH = 11.9%) was increased 30-fold (t1/2 = 45 ± 5 min). Simultaneously, the solubility of gluten was increased by 60%. Buffalo worm hydrolysates (DH = 14.6%) had a twofold (t1/2 = 85 ± 5 min) increased emulsion stability. In conclusion, AprX can be used to improve the solubility and emulsifying properties of food proteins at a relatively high DH.
Construction and description of a constitutive plipastatin mono-producing Bacillus subtilis
(2020) Vahidinasab, Maliheh; Lilge, Lars; Reinfurt, Aline; Pfannstiel, Jens; Henkel, Marius; Morabbi Heravi, Kambiz; Hausmann, Rudolf
Background: Plipastatin is a potent Bacillus antimicrobial lipopeptide with the prospect to replace conventional antifungal chemicals for controlling plant pathogens. However, the application of this lipopeptide has so far been investigated in a few cases, principally because of the yield in low concentration and unknown regulation of biosynthesis pathways. B. subtilis synthesizes plipastatin by a non-ribosomal peptide synthetase encoded by the ppsABCDE operon. In this study, B. subtilis 3NA (a non-sporulation strain) was engineered to gain more insights about plipastatin mono-production. Results: The 4-phosphopantetheinyl transferase Sfp posttranslationally converts non-ribosomal peptide synthetases from inactive apoforms into their active holoforms. In case of 3NA strain, sfp gene is inactive. Accordingly, the first step was an integration of a repaired sfp version in 3NA to construct strain BMV9. Subsequently, plipastatin production was doubled after integration of a fully expressed degQ version from B. subtilis DSM10T strain (strain BMV10), ensuring stimulation of DegU-P regulatory pathway that positively controls the ppsABSDE operon. Moreover, markerless substitution of the comparably weak native plipastatin promoter (Ppps) against the strong constitutive promoter Pveg led to approximately fivefold enhancement of plipastatin production in BMV11 compared to BMV9. Intriguingly, combination of both repaired degQ expression and promoter exchange (Ppps::Pveg) did not increase the plipastatin yield. Afterwards, deletion of surfactin (srfAA-AD) operon by the retaining the regulatory comS which is located within srfAB and is involved in natural competence development, resulted in the loss of plipastatin production in BMV9 and significantly decreased the plipastatin production of BMV11. We also observed that supplementation of ornithine as a precursor for plipastatin formation caused higher production of plipastatin in mono-producer strains, albeit with a modified pattern of plipastatin composition. Conclusions: This study provides evidence that degQ stimulates the native plipastatin production. Moreover, a full plipastatin production requires surfactin synthetase or some of its components. Furthermore, as another conclusion of this study, results point towards ornithine provision being an indispensable constituent for a plipastatin mono-producer B. subtilis strain. Therefore, targeting the ornithine metabolic flux might be a promising strategy to further investigate and enhance plipastatin production by B. subtilis plipastatin mono-producer strains.
Consumption of yeast-fermented wheat and rye breads increases colitis and mortality in a mouse model of colitis
(2022) Zimmermann, Julia; De Fazio, Luigia; Kaden-Volynets, Valentina; Hitzmann, Bernd; Bischoff, Stephan C.
Background: Cereals are known to trigger for wheat allergy, celiac disease and non-celiac wheat sensitivity (NCWS). Inflammatory processes and intestinal barrier impairment are suspected to be involved in NCWS, although the molecular triggers are unclear. Aims: We were interested if different bread types influence inflammatory processes and intestinal barrier function in a mouse model of inflammatory bowel disease. Methods: Epithelial caspase-8 gene knockout (Casp8 ΔIEC ) and control (Casp8 fl ) mice were randomized to eight groups, respectively. The groups received different diets for 28 days (gluten-free diet, gluten-rich diet 5 g%, or different types of bread at 50 g%). Breads varied regarding grain, milling and fermentation. All diets were isocaloric. Results: Regardless of the diet, Casp8 ΔIEC mice showed pronounced inflammation in colon compared to ileum, whereas Casp8 fl mice were hardly inflamed. Casp8 fl mice could tolerate all bread types. Especially yeast fermented rye and wheat bread from superfine flour but not pure gluten challenge increased colitis and mortality in Casp8 ΔIEC mice. Hepatic expression of lipopolysaccharide-binding protein and colonic expression of tumor necrosis factor-α genes were inversely related to survival. The bread diets, but not the gluten-rich diet, also decreased colonic tight junction expression to variable degrees, without clear association to survival and inflammation. Conclusions: Bread components, especially those from yeast-fermented breads from wheat and rye, increase colitis and mortality in Casp8 ΔIEC mice highly susceptible to intestinal inflammation, whereas control mice can tolerate all types of bread without inflammation. Yet unidentified bread components other than gluten seem to play the major role.
A diamine oxidase from Glutamicibacter halophytocola for the degradation of histamine and tyramine in foods
(2025) Kettner, Lucas; Freund, Alexander; Bechtel, Anna; Costa-Catala, Judit; Fischer, Lutz; Kettner, Lucas; Department of Biotechnology and Enzyme Science, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstr. 25, 70599 Stuttgart, Germany; Freund, Alexander; Department of Biotechnology and Enzyme Science, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstr. 25, 70599 Stuttgart, Germany; Bechtel, Anna; Department of Biotechnology and Enzyme Science, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstr. 25, 70599 Stuttgart, Germany; Costa-Catala, Judit; Departament de Nutrició, Ciències de l’Alimentació i Gastronomia, Campus de l’Alimentació de Torribera, Universitat de Barcelona, Av. Prat de la Riba 171, 08921 Santa Coloma de Gramenet, Spain; Fischer, Lutz; Department of Biotechnology and Enzyme Science, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstr. 25, 70599 Stuttgart, Germany
A novel diamine oxidase (DAO) was discovered in the bacterium Glutamicibacter halophytocola (DAO-GH). The gene of DAO-GH was integrated into the genome of the yeast Komagataella phaffii and recombinantly produced under control of the methanol-inducible AOX1 promoter in a bioreactor cultivation. A high DAO activity of 70.2 ± 5.2 µkat/Lculture (5.25 ± 0.22 µkat/gprotein) was yielded after 90 h of cultivation. The DAO-GH was partially purified by the polyethyleneimine precipitation of nucleic acids, fractionated ammonium sulfate precipitation and hydrophobic interaction chromatography, resulting in a specific DAO activity of 19.7 µkat/gProtein. The DAO-GH was then biochemically investigated regarding its potential for histamine and tyramine degradation in fermented foods and the human small intestine. Interestingly, the DAO-GH showed activity even at a low pH of 5 and low temperature of 6 °C. Both histamine and tyramine were effectively degraded and DAO-GH showed especially very high affinity towards tyramine (Km of 0.009 mM). The DAO-GH was shown to be capable of degrading around 20% of the initially applied histamine in tuna paste (pH 5.6) at 5 °C within 24 h and completely degraded the histamine in a simulated intestinal fluid within 1.5 h in bioconversion experiments. The DAO-GH was spray-dried for the production of a storable enzyme preparation. Only around 17% of activity were lost in this process and the DAO-GH remained stable at room temperature for at least 3 months. The discovery of this DAO with its very advantageous biochemical properties allows the preparation of histamine-reduced or -free fermented foods by a simple enzymatic treatment or the treatment of histamine intolerance symptoms as a dietary supplement or medicine.
Food fermentation: an essential unit operation towards secure, sustainable, safe, and sustaining food systems
(2025) Gänzle, Michael G.; Seifert, Jana; Weiss, Jochen; Zijlstra, Ruurd T.
Food informatics - Review of the current state-of-the-art, revised definition, and classification into the research landscape
(2021) Krupitzer, Christian; Stein, Anthony
Background: The increasing population of humans, changing food consumption behavior, as well as the recent developments in the awareness for food sustainability, lead to new challenges for the production of food. Advances in the Internet of Things (IoT) and Artificial Intelligence (AI) technology, including Machine Learning and data analytics, might help to account for these challenges. Scope and Approach: Several research perspectives, among them Precision Agriculture, Industrial IoT, Internet of Food, or Smart Health, already provide new opportunities through digitalization. In this paper, we review the current state-of-the-art of the mentioned concepts. An additional concept is Food Informatics, which so far is mostly recognized as a mainly data-driven approach to support the production of food. In this review paper, we propose and discuss a new perspective for the concept of Food Informatics as a supportive discipline that subsumes the incorporation of information technology, mainly IoT and AI, in order to support the variety of aspects tangent to the food production process and delineate it from other, existing research streams in the domain. Key Findings and Conclusions: Many different concepts related to the digitalization in food science overlap. Further, Food Informatics is vaguely defined. In this paper, we provide a clear definition of Food Informatics and delineate it from related concepts. We corroborate our new perspective on Food Informatics by presenting several case studies about how it can support the food production as well as the intermediate steps until its consumption, and further describe its integration with related concepts.
Genome-wide association reveals host-specific genomic traits in Escherichia coli
(2023) Tiwari, Sumeet K.; van der Putten, Boas C. L.; Fuchs, Thilo M.; Vinh, Trung N.; Bootsma, Martin; Oldenkamp, Rik; La Ragione, Roberto; Matamoros, Sebastien; Hoa, Ngo T.; Berens, Christian; Leng, Joy; Álvarez, Julio; Ferrandis-Vila, Marta; Ritchie, Jenny M.; Fruth, Angelika; Schwarz, Stefan; Domínguez, Lucas; Ugarte-Ruiz, María; Bethe, Astrid; Huber, Charlotte; Johanns, Vanessa; Stamm, Ivonne; Wieler, Lothar H.; Ewers, Christa; Fivian-Hughes, Amanda; Schmidt, Herbert; Menge, Christian; Semmler, Torsten; Schultsz, Constance
Background: Escherichia coli is an opportunistic pathogen which colonizes various host species. However, to what extent genetic lineages of E. coli are adapted or restricted to specific hosts and the genomic determinants of such adaptation or restriction is poorly understood. Results: We randomly sampled E. coli isolates from four countries (Germany, UK, Spain, and Vietnam), obtained from five host species (human, pig, cattle, chicken, and wild boar) over 16 years, from both healthy and diseased hosts, to construct a collection of 1198 whole-genome sequenced E. coli isolates. We identified associations between specific E. coli lineages and the host from which they were isolated. A genome-wide association study (GWAS) identified several E. coli genes that were associated with human, cattle, or chicken hosts, whereas no genes associated with the pig host could be found. In silico characterization of nine contiguous genes (collectively designated as nan-9 ) associated with the human host indicated that these genes are involved in the metabolism of sialic acids (Sia). In contrast, the previously described sialic acid regulon known as sialoregulon (i.e. nanRATEK-yhcH , nanXY , and nanCMS ) was not associated with any host species. In vitro growth experiments with a Δ nan-9 E. coli mutant strain, using the sialic acids 5- N -acetylneuraminic acid (Neu5Ac) and N -glycolylneuraminic acid (Neu5Gc) as sole carbon source, showed impaired growth behaviour compared to the wild-type. Conclusions: This study provides an extensive analysis of genetic determinants which may contribute to host specificity in E. coli . Our findings should inform risk analysis and epidemiological monitoring of (antimicrobial resistant) E. coli .
Integrating sensor data, laboratory analysis, and computer vision in machine learning-driven E-Nose systems for predicting tomato shelf life
(2025) Senge, Julia Marie; Kaltenecker, Florian; Krupitzer, Christian
Assessing the quality of fresh produce is essential to ensure a safe and satisfactory product. Methods to monitor the quality of fresh produce exist; however, they are often expensive, time-consuming, and sometimes require the destruction of the sample. Electronic Nose (E-Nose) technology has been established to track the ripeness, spoilage, and quality of fresh produce. Our study developed a freshness monitoring system for tomatoes, combining E-Nose technology with storage condition monitoring, color analysis, and weight-loss tracking. Different post-purchase scenarios were investigated, focusing on the influence of temperature and mechanical damage on shelf life. Support Vector Classifier (SVC) and k-Nearest Neighbor (kNN) were applied to classify storage scenarios and storage days, while Support Vector Regression (SVR) and kNN regression were used for predicting storage days. By using a data fusion approach with Linear Discriminant Analysis (LDA), the SVC achieved an accuracy of 72.91% in predicting storage days and an accuracy of 86.73% in distinguishing between storage scenarios. The kNN yielded the best regression results, with a Mean Absolute Error (MAE) of 0.841 days and a coefficient of determination of 0.867. The results highlight the method’s potential to predict storage scenarios and storage days, providing insight into the product’s remaining shelf life.
Investigation of biochars in terms of vitamin E adsorption capacity
(2025) Witte, Franziska; Dinh, Ngoc Huyen Anh; Juadjur, Andreas; Heinz, Volker; Visscher, Christian; Weiss, Jochen; Terjung, Nino; Gao, Bin; García Rodríguez, Juan
Featured Application: This study provides insights into optimising biochar as a carrier for vitamin E delivery in ruminant nutrition. By demonstrating the correlation between pore size distribution and adsorption capacity, the findings suggest that theoretical models can reduce the number of experimental trials needed to identify effective adsorbents. This approach could improve the efficiency of vitamin E supplementation in animal feed, potentially enhancing nutrient absorption and animal health. Abstract: Vitamin E is important for ruminants’ health. To increase the rate of vitamin E resorption, the use of a carrier is recommended. One authorised porous feed additive is biochar. Biochar’s adsorption capacity is affected by its pore volume, which is determined, among other factors, by the biomass and the production process applied. For this purpose, the vitamin E adsorption capacity of ten commercial biochars with a varying surface area in the range of 2.6 to 20 nm was investigated. The results of these single-point batch experiments were compared to the theoretical results using a monolayer adsorption model. Our hypothesis was proven, as the theoretical model could predict the experimental adsorption capacity. This generally suggests that the number of trials required to identify optimal adsorbents can be reduced. A high percentage of vitamin E adsorption (>90%) was obtained with a short adsorption time of 10 min using an adsorbent dosage of 15.78 g/L and a vitamin E concentration of 1.70 g/L. The highest correlation of vitamin E adsorption existed for the mesopore class, ranging from 3.22 to 4.03 nm in Barrett–Joyner–Halenda surface area. This indicates the necessity of knowing the size of the adsorptive and the adsorbent in order to optimise sorption kinetics.
Poultry perfection : comparison of computer vision models to detect and classify poultry products in a production setting
(2025) Einsiedel, Daniel; Vita, Marco; Jox, Dana; Dunnewind, Bertus; Meulendijks, Johan; Krupitzer, Christian
This study explores the use of computer vision, specifically object detection, for quality control in ready-to-eat meat products. We focused on a single process step, labeling products as “good” or “imperfect”. An “imperfect product” constitutes a product that deviates from the norm regarding shape, size, or color (having a hole, missing edges, dark particles, etc.). Imperfect does not mean the product is inedible or a risk to food safety, but it affects the overall product quality. Various object detectors, such as YOLO, including YOLO12, were compared using the mAP50-95 metric. Most models achieved mAP scores over 0.9, with YOLO12 reaching a peak score of 0.9359. The precision and recall curves indicated that the model learned the “imperfect product” class better, most likely due to its higher representation. This underscores the importance of a balanced dataset, which is challenging to achieve in real-world settings. The confusion matrix revealed false positives, suggesting that increasing dataset volume or hyperparameter tuning could help. However, increasing the dataset volume is usually the more difficult path since data acquisition and especially labeling are by far the most time-consuming steps of the whole process. Overall, current models can be applied to quality control tasks with some margin of error. Our experiments show that high-quality, consistently labeled datasets are potentially more important than the choice of the model for achieving good results. The applied hyperparameter tuning on the YOLO12 model did not outperform the default model in this case. Future work could involve training models on a multi-class dataset with hyperparameter optimization. A multi-class dataset could contain more specific classes than just “good” and “imperfect,” making trained models capable of actually predicting specific quality deviations.
Recombinant production of bovine αS1-casein in genome-reduced Bacillus subtilis strain IIG-Bs-20-5-1
(2025) Biermann, Lennart; Tadele, Lea Rahel; Benatto Perino, Elvio Henrique; Nicholson, Reed; Lilge, Lars; Hausmann, Rudolf; Fouillaud, Mireille
Background: Cow’s milk represents an important protein source. Here, especially casein proteins are important components, which might be a promising source of alternative protein production by microbial expression systems. Nevertheless, caseins are difficult-to-produce proteins, making heterologous production challenging. However, the potential of genome-reduced Bacillus subtilis was applied for the recombinant production of bovine αS1-casein protein. Methods: A plasmid-based gene expression system was established in B. subtilis allowing the production of his-tagged codon-optimized bovine αS1-casein. Upscaling in a fed-batch bioreactor system for high cell-density fermentation processes allowed for efficient recombinant αS1-casein production. After increasing the molecular abundance of the recombinant αS1-casein protein using immobilized metal affinity chromatography, zeta potential and particle size distribution were determined in comparison to native bovine αS1-casein. Results: Non-sporulating B. subtilis strain BMV9 and genome-reduced B. subtilis strain IIG-Bs-20-5-1 were applied for recombinant αS1-casein production. Casein was detectable only in the insoluble protein fraction of the genome-reduced B. subtilis strain. Subsequent high cell-density fed-batch bioreactor cultivations using strain IIG-Bs-20-5-1 resulted in a volumetric casein titer of 56.9 mg/L and a yield of 1.6 mgcasein/gCDW after reducing the B. subtilis protein content. Comparative analyses of zeta potential and particle size between pre-cleaned recombinant and native αS1-casein showed pH-mediated differences in aggregation behavior. Conclusions: The study demonstrates the potential of B. subtilis for the recombinant production of bovine αS1-casein and underlines the potential of genome reduction for the bioproduction of difficult-to-produce proteins.
Spatial transcriptomics of a parasitic flatworm provides a molecular map of drug targets and drug resistance genes
(2024) Gramberg, Svenja; Puckelwaldt, Oliver; Schmitt, Tobias; Lu, Zhigang; Haeberlein, Simone; Gramberg, Svenja; Institute of Parasitology, Justus Liebig University Giessen, Giessen, Germany; Puckelwaldt, Oliver; Institute of Parasitology, Justus Liebig University Giessen, Giessen, Germany; Schmitt, Tobias; Institute of Parasitology, Justus Liebig University Giessen, Giessen, Germany; Lu, Zhigang; Institute of Food Science and Biotechnology, University of Hohenheim, Stuttgart, Germany; Haeberlein, Simone; Institute of Parasitology, Justus Liebig University Giessen, Giessen, Germany
The spatial organization of gene expression dictates tissue functions in multicellular parasites. Here, we present the spatial transcriptome of a parasitic flatworm, the common liver fluke Fasciola hepatica . We identify gene expression profiles and marker genes for eight distinct tissues and validate the latter by in situ hybridization. To demonstrate the power of our spatial atlas, we focus on genes with substantial medical importance, including vaccine candidates (Ly6 proteins) and drug resistance genes (glutathione S-transferases, ABC transporters). Several of these genes exhibit unique expression patterns, indicating tissue-specific biological functions. Notably, the prioritization of tegumental protein kinases identifies a PKCβ, for which small-molecule targeting causes parasite death. Our comprehensive gene expression map provides unprecedented molecular insights into the organ systems of this complex parasitic organism, serving as a valuable tool for both basic and applied research.
Spectroscopic analysis of chia seeds
(2021) Mburu, Monica; Paquet-Durand, Olivier; Hitzmann, Bernd; Zettel, Viktoria
Chia seeds are becoming more and more popular in modern diets. In this contribution NIR and 2D-fluorescence spectroscopy were used to determine their nutritional values, mainly fat and protein content. 25 samples of chia seeds were analysed, whereof 9 samples were obtained from different regions in Kenya, 16 samples were purchased in stores in Germany and originated mostly from South America. For the purchased samples the nutritional information of the package was taken in addition to the values obtained for fat and protein, which were determined at the Hohenheim Core Facility. For the first time the NIR and fluorescence spectroscopy were used for the analysis of chia. For the spectral evaluation two different pre-processing methods were tested. Baseline correction with subsequent mean-centring lead to the best results for NIR spectra whereas SNV (standard normal variate transformation) was sufficient for the evaluation of fluorescence spectra. When combining NIR and fluorescence spectra, the fluorescence spectra were also multiplied with a factor to adjust the intensity levels. The best prediction results for the evaluation of the combined spectra were obtained for Kenyan samples with prediction errors below 0.2 g/100 g. For all other samples the absolute prediction error was 0.51 g/100 g for fat and 0.62 g/100 g for protein. It is possible to determine the amount of protein and fat of chia seeds by fluorescence and NIR spectroscopy. The combination of both methods is beneficial for the predictions. Chia seeds from Kenya had similar protein and lipid contents as South American seeds.
Storable cheese curd—effect of milk homogenization as a pre-treatment and freezing and extrusion of cheese curd on production of pasta filata style cheese
(2024) Schmidt, Florian; Graf, Britta; Hinrichs, Jörg; Schmidt, Florian; Institute of Food Science and Biotechnology, Department of Soft Matter Science and Dairy Technology, University of Hohenheim, Garbenstrasse 21, 70599, Stuttgart, Germany; Graf, Britta; Institute of Food Science and Biotechnology, Department of Soft Matter Science and Dairy Technology, University of Hohenheim, Garbenstrasse 21, 70599, Stuttgart, Germany; Hinrichs, Jörg; Institute of Food Science and Biotechnology, Department of Soft Matter Science and Dairy Technology, University of Hohenheim, Garbenstrasse 21, 70599, Stuttgart, Germany
This study investigates the production of pasta filata style cheese from a storable, frozen intermediate material. Homogenization (2–16 MPa, single-staged) of milk (fat/protein = 0.9) was used as a tool to decrease fat globule size and consequently fat losses. Plasticization was achieved by using a single-screw extruder set up with double-jacketed hot water cycle. Non-frozen and frozen cheese curd as well as the extruded pasta filata style cheese pre-treated with different homogenization pressure was analyzed regarding the thermo-rheological properties. Fat and protein gain/loss during extrusion was evaluated by analyzing fat in dry matter (FDM) and protein in dry matter (PDM) before and after extrusion. Homogenization of cheese milk leads to a reduction of tan δ for thereof produced raw cheese curd material as well as the extruded products. Freezing and extrusion counteract the reduction of tan δ . A homogenization pressure of 8 MPa is sufficient to prevent fat losses during extrusion while still maintaining plasticization of the product for fresh and frozen material, respectively. The FDM after extrusion is 0.8% higher for fresh material and 4.9% higher for frozen material, which means that the fat concentrates during extrusion due to water loss. Moreover, there is no loss of PDM for all samples, regardless of the homogenization pressure. A combination of homogenization pressure, freezing, and extrusion leads to a plasticizable product without losses of fat and protein. Hence, frozen cheese curd can be used as a storable intermediate.
Time-delayed cold gelation of low-ester pectin and gluten with CaCO3 to facilitate manufacture of raw-fermented vegan sausage analogs
(2025) Koenig, Maurice; Ahlborn, Kai; Herrmann, Kurt; Loeffler, Myriam; Weiss, Jochen; Kolanowski, Wojciech
To advance the development of protein-rich plant-based foods, a novel binder system for vegan sausage alternatives without the requirement of heat application was investigated. This enables long-term ripening of plant-based analogs similar to traditional fermented meat or dairy products, allowing for refined flavor and texture development. This was achieved by using a poorly water-soluble calcium source (calcium carbonate) to introduce calcium ions into a low-ester pectin—gluten matrix susceptible to crosslinking via divalent ions. The gelling reaction of pectin–gluten dispersions with Ca 2+ ions was time-delayed due to the gradual production of lactic acid during fermentation. Firm, sliceable matrices were formed, in which particulate substances such as texturized proteins and solid vegetable fat could be integrated, hence forming an unheated raw-fermented plant-based salami-type sausage model matrix which remained safe for consumption over 21 days of ripening. Gluten as well as pectin had a significant influence on the functional properties of the matrices, especially water holding capacity (increasing with higher pectin or gluten content), hardness (increasing with higher pectin or gluten content), tensile strength (increasing with higher pectin or gluten content) and cohesiveness (decreasing with higher pectin or gluten content). A combination of three simultaneously occurring effects was observed, modulating the properties of the matrices, namely, (a) an increase in gel strength due to increased pectin concentration forming more brittle gels, (b) an increase in gel strength with increasing gluten content forming more elastic gels and (c) interactions of low-ester pectin with the gluten network, with pectin addition causing increased aggregation of gluten, leading to strengthened networks.
Using ground oyster mushroom and chia seeds for the fortification of wheat bread-Nelder–Mead simplex optimisation
(2025) Schneider, Yannik; Zettel, Viktoria
Wheat bread was enriched with ground chia and ground oyster mushroom to improve its nutritional properties regarding protein and fibre content within the context of food fortification while maintaining a high specific volume and a soft crumb. A bread made from 100% wheat flour was used as reference. The Nelder–Mead simplex algorithm was used to determine the optimal proportions of chia and oyster mushroom substitution in the recipe. Bread quality was analysed and rated. Chia has a positive effect on the baking result due to its water-binding capacity, while mushrooms have a rather negative effect caused by the enzymes they contain. It was possible to replace 1.6% of wheat flour with ground oyster mushroom and 1.2% chia without any deviations from the control within 7 steps Furthermore, the partially substituted breads showed 3.8% lower contents of carbohydrates with a reduction of 4.1% of total sugar and higher contents of dietary fibre and protein, 22.7% and 2.3% respectively in comparison with the control sample. The wheat flour in bread can be replaced by chia flour and ground oyster mushrooms in small quantities without compromising the quality of the bread while improving some nutritional values.

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