Simon Dirr

Due to its high-protein content of 60–70% on dry weight, Arthrospira platensis, has been considered as one of the most sought-after protein alternatives. However, the processing of Arthrospira platensis extract (spirulina, SP) in food is usually limited due to the strong green colour and taste, as well as the lack of bioavailability of plant proteins. Therefore, this study aimed to increase its use in food applications through technologies such as microencapsulation by spray drying and enzymatic treatment. The effect of different combinations of maltodextrin (MD) and gum arabic (GA) as coating material were tested in ratios of 1:2 and 1:4 for Arthrospira platensis, core to wall material, respectively. Additionally, enzymatic treatment was used to investigate whether digestibility, protein solubility and powder solubility can be improved. Thermal stability was examined by differential scanning calorimetry (DSC), and colour intensity was analysed over L* a* b* colour system. The sample SP-MD1:2 showed the highest heat stability with a denaturation peak at 67 °C, while the samples SP-MD1:4 and ESP-MD1:4 revealed the best brightening effects. The crude protein content stated by the manufacturer of 67% was confirmed. Encapsulation and enzymatic hydrolysis enhance the protein solubility, under which ESP-MD1:4 had the greatest solubility at around 83%. The protein digestibility peaks were around 99% with sample SP-MD1:2.

Aim: This study aimed to compare the efficiency of protein extraction methods from stinging nettle leaves. Focusing on the application of pulsed electric fields (PEF) combined with proteolytic enzymes, extraction with Fusarium spp. fermentation and conventional extraction. The objective was to evaluate the effectiveness of each method in terms of protein yield and potential applications in the food industry. Method: Stinging nettle leaves were treated with three different extraction methods: (1) PEF treatment combined with the use of proteolytic enzymes, (2) fermentation with Fusarium spp. to extract proteins and (3) conventional extraction through alkaline solubilization and acid precipitation. The protein extraction processes were optimized, and the extracted proteins were analyzed for their yield, and functional properties. Result: The PEF and proteolytic enzymes extraction method yielded a higher protein content (75,9% ± 1,5) compared to the extraction through Fusarium spp. Fermentation (54,5% ± 1,4). With the conventional method the proteincontent reached 53,8% ± 0,4 The combination of PEF and proteolytic enzymes efficiently disrupted the plant cells, resulting in enhanced protein release. Additionally, the proteins demonstrated functional properties suitable for various food applications, such as solubility and geling abilitys in a joghurt. In contrast, the proteins obtained from Fusarium spp. fermentation showed a slightly lower protein yield and differed strongly in the sensory profile. Conclusion: This study highlights the comparison of three protein extraction methods from stinging nettle leaves, specifically comparing PEF and the use of proteolytic enzymes, extracting via fermentation by Fusarium spp. and conventional methods. The PEF and proteolytic enzymes approach demonstrated superior protein extraction efficiency, resulting in higher protein content. The extracted proteins exhibited functional properties suitable for diverse food applications. While the Fusarium spp. fermentation method also yielded proteins, its efficiency and sensory profile were lower than the PEF and proteolytic enzymes method. This study provides valuable insights into the selection of appropriate protein extraction techniques and highlights the potential of PEF and proteolytic enzymes for efficient protein extraction from plant sources. Future research can focus on further optimizing the extraction conditions, the sensory aspects, improve the colour intensity and evaluate the sustainability aspects of these methods.

Aim: This study aims to compare the efficiency of protein extraction from chia seeds (Salvia hispanica L.), with a specific focus on the influence of different defatting processes. Traditional defatting methods, such as the use of solvents like hexane or ethanol, are commonly recommended and generally regarded as safe. However, due to growing environmental and sustainability concerns, there is increasing interest in exploring more eco-friendly alternatives, such as supercritical CO2 extraction. The objective is to evaluate the effectiveness of each defatting method in terms of protein yield and their potential applications in the food industry, while considering their impact on functional properties. Method: Chia seeds were subjected to four distinct fat extraction methods: No defatting (control) Mechanical defatting Defatting using supercritical CO2 with ethanol Conventional defatting with hexane Following defatting, the protein extraction processes were optimized for each method. The extracted proteins were then analyzed for yield and functional properties, including solubility, emulsifying capacity, stability, and water/oil holding capacities, to assess their suitability for food industry applications. Result: Preliminary trials have shown significant variations in protein yield and functional properties across the different extraction and defatting methods. Protein yields from personal trials ranged between 27% and 45%, while literature reports yields between 73% and 79% depending on the method used. Functional properties also varied significantly: Solubility: 39-56% Emulsifying capacity: 161-203% Oil holding capacity: 186-474% Water holding capacity: 235-753% These variations suggest that the choice of defatting method has a substantial impact on both protein yield and functional characteristics. Conclusion: The study highlights the potential benefits of alternative fat extraction methods for improving protein yield and functional properties from chia seeds. Supercritical CO2 extraction and mechanical defatting methods showed particularly promising results compared to conventional hexane-based approaches. These methods not only maximize protein yield but also enhance functional properties, which could have significant implications for food product development and formulation. Further research is needed to optimize these alternative extraction techniques for industrial-scale application and fully realize their environmental and economic benefits.