Phylogenetic comparative analysis: Chemical and biological features of caseins (alpha-S-1, alpha-S-2, beta- and kappa-) in domestic dairy animals

Casein-based film enriched with lignin as a biodegradable substrate for enzyme immobilization

In the last decades, the negative impact of petroleum derived materials on the environment is more and more evident; beyond the unavoidable reduction in the use of classical plastic, another promising approach is the development of alternative materials prepared starting from natural, biodegradable, and more sustainable biomolecules, particularly undervalued or discarded ones. Caseins are the most abundant proteins in milk, with important nutritional value but also interesting film-forming properties. Lignin is a polyphenolic polymer found in wood and derived from a by-product of the cellulose extraction processes; it is well known for its antibacterial, antioxidant, and UV-protecting properties. In the present work, casein was isolated from UHT skimmed bovine milk through acidification and used alone or in combination with lignin to produce films that are biodegradable and environmentally friendly. Casein and casein-lignin films presented a thickness in the range of 180-260 μm and a compact, non-porous texture. The presence of lignin did not affect the morphology of the films but influenced their mechanical properties. For casein and casein-lignin films covalently crosslinked with transglutaminase (TGM), the solubility decreased to 40-50% and the samples retained their shape. The results show that TGM-containing films are suitable as substrates for the immobilization of enzymes; herein, the FAD-dependent glucose oxidase from Aspergillus niger was added to the film and the enzyme remained stable and active against glucose for weeks, as demonstrated by the colorimetric detection of the H2O2 produced in the catalysed reaction. This study opens up the possibility of combining two products of natural origin for the production of films through processes with low environmental impact, thus offering interesting scenarios in the immobilization of macromolecules for the detection of target molecules.

Impact of high-pressure treatments on physicochemical and structural changes of reconstituted micellar casein concentrates from bovine and caprine milk: A comparative study

This study investigated the effect of high-pressure processing (HPP) on the physicochemical and structural changes in reconstituted micellar CN concentrates (MCC) sourced from bovine (BMCC) and caprine (CMCC) milk. When applying pressures ranging from 100 to 500 MPa for 30 min at 25 ± 2°C, it was observed that BMCC exhibited a notable increase in soluble minerals and solubility percentages with a simultaneous reduction in particle size and zeta potential compared with CMCC. In BMCC, Ca and P solubility rose from 27.71% and 33.02% to 90.33% and 92.01%, respectively. In CMCC, the solubility of Ca and P increased from 36.12% and 38.29% at 100 MPa to 52.57% and 56.77% at 500 MPa. Additionally, the reduction in particle size was more pronounced in BMCC, with a 53% decrease at 500 MPa, compared with a 19.90% reduction in CMCC. Furthermore, fluorescence intensity, indicative of surface hydrophobicity, decreased in BMCC samples (from 3,478 to 2,571 arbitrary units [a.u.]), whereas it increased in CMCC samples (from 2,388 to 4,058 a.u.) across the same pressure range. Comparative analysis revealed that HPP-treated CMCC samples exhibited a decline in α-helix content until the treatment at 300 MPa, followed by an increase post-treatment at 500 MPa. Additionally, a rise in β-sheet structure content was observed, except for the sample treated at 500 MPa, where β-sheet content significantly decreased. These findings suggest that HPP holds promise as a viable technological approach in the dairy sector for enhancing the functional characteristics of CMCC.

Which casein micelle removal method is suitable for studies of human milk extracellular vesicles? A systematic comparison of four different treatments for casein depletion before extracellular vesicle isolation from human milk

Aim: This study aimed to systematically compare four casein micelle removal methods on the particle and protein characteristics of the isolated human milk EVs. Methods: The defatted milk was treated with 1% sodium citrate, 20 mM ethylenediaminetetraacetic acid (EDTA), 1% acetic acid, or 1% chymosin/calcium chloride for 30 min at 4 °C to remove casein micelles. EV isolation was performed using qEV size exclusion chromatography. Milk turbidity at the optical density 350 nm and dot immunoblot with casein antibody were applied to monitor the qEV fractions. Particle analyses were performed using transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA). The enrichment of human milk EV markers, i.e., tetraspanins, Alix, lactadherin, butyrophilin, and xanthine dehydrogenase, and casein depletion capabilities were evaluated by proteomics and immunoblotting. Results: Compared to the untreated condition, sodium citrate and EDTA decreased milk turbidity by disrupting casein micelles, while acetic acid and chymosin removed them by inducing precipitation/coagulation. All treatments shifted casein immunoreactivity in the qEV fractions from large micelles (the exclusion volume) to small molecular sizes (gel-infiltrated fractions). Acidification affected human milk EV morphology, while EDTA, acetic acid, and chymosin methods slightly altered EV particle numbers. Different casein micelle removal methods confer different degrees of human milk EV marker enrichment and casein depletion. The method performances could be ranked as follows: chymosin > EDTA > acetic acid > sodium citrate. Conclusion: Our findings suggest that chymosin and EDTA should be considered as the method of choice for casein micelle removal in future studies involving human milk EV isolation and characterization.

Gamma-rays induced mutations increase soybean oil and protein contents

Mutation breeding is one of the effective techniques used for improving desired traits such as yield quality and quantity in economic crops. The present study aims to develop oil and protein contents in addition to high yield attributes in soybean using gamma rays as a mutagen. Seeds of the soybean genotypes Giza 21, Giza 22, Giza 82, Giza 83 and 117 were treated with gamma rays doses 50, 100, 200 and 300 Gy. Plants were then scored based on morphological parameters correlated with yield quantity including plant height, seed weight and valuable protein and oil contents. Mutant lines exhibiting the highest yield attributes were selected and used as parents for M2 generation. The M2 progeny was further assessed based on their ability to maintain their yield attributes. Twenty mutant lines were selected and used as M3 lines. The yield parameters inferred a positive effect of gamma irradiation on the collected M3 mutant lines compared to their parental genotypes. 100 Gy of gamma rays gave the highest effect on the number of pods, branches and seeds per plant in addition to protein content, while 200 Gy was more effective in increasing plant height, number of pods per plant, and oil content. Six mutant lines scored the highest yield parameters. Further assessment inferred an inverse relationship between oil and protein content in most of the tested cultivars with high agronomic features. However, four mutant lines recorded high content of oil and protein besides their high seed yield as well, which elect them as potential candidates for large-scale evaluation. The correlation among examined parameters was further confirmed via principal component analysis (PCA), which inferred a positive correlation between the number of pods, branches, seeds, and seed weight. Conversely, oil and protein content were inversely correlated in most of yielded mutant lines. Together, those findings introduce novel soybean lines with favorable agronomic traits for the market. In addition, our research sheds light on the value of using gamma rays treatment in enhancing genetic variability in soybean and improving oil, protein contents and seed yield.

Improvement of German Chamomile (Matricaria recutita L.) for Mechanical Harvesting, High Flower Yield and Essential Oil Content Using Physical and Chemical Mutagenesis

Chamomile (Matricariarecutita L.) is one of the most important medicinal plants with various applications. The flowers and flower heads are the main organs inthe production of essential oil. The essential improvement goals of chamomile are considered to be high flower yield and oil content, as well asthe suitability for mechanical harvesting. The present study aimed to improve the flower yield, oil content and mechanical harvestability of German chamomile via chemical and physical mutagens. Three German chamomile populations (Fayum, Benysuif and Menia) were irradiated with 100, 200, 300 and 400 Gray doses of gamma rays, as well as chemically mutagenized using 0.001, 0.002 and 0.003 mol/mL of sodium azide for 4 h. The two mutagens produced a wide range of changes in the flowers' shape and size. At M₃ generation, 18 mutants (11 from gamma irradiation and 7 from sodium azide mutagenization) were selected and morphologically characterized. Five out of eighteen mutants were selected for morphological and chemical characterization for oil content, oil composition and oil quality in M₄ generation. Two promising mutants, F/LF5-2-1 and B/HNOF 8-4-2, were selected based on their performance in most studied traits during three generations, as well as the high percentage of cut efficiency and a homogenous flower horizon, which qualify them as suitable candidates for mechanical harvesting. The two mutants are late flowering elite mutants; the F/LF5-2-1 mutant possessed the highest oil content (1.77%) and number of flowers/plant (1595), while the second promising B/HNOF 8-4-2 mutant hada high oil content (1.29%) and chamazulene percentage (13.98%) compared to control plants. These results suggest that the B/HNOF 8-4-2 and F/LF5-2-1 mutants could be integrated as potential parents into breeding programs for a high number of flowers, high oil content, oil composition and oil color traits for German chamomile improvement.