Ultrasonic microencapsulation of oil-soluble vitamins by hen egg white and green tea for fortification of food.
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ABSTRACT:
SUBMITTER: Zhu H
PROVIDER: S-EPMC8164159 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Assembly and deposition of insoluble amyloid fibrils with a distinctive cross-?-sheet structure is the molecular hallmark of amyloidogenic diseases affecting the central nervous system as well as non-neuropathic amyloidosis. Amyloidogenic proteins form aggregates via kinetic pathways dictated by initial solution conditions. Often, early stage, cytotoxic, small globular amyloid oligomers (gOs) and curvilinear fibrils (CFs) precede the formation of late-stage rigid fibrils (RFs). Growing experimental evidence suggests that soluble gOs are off-pathway aggregates that do not directly convert into the final stage RFs. Yet, the kinetics of RFs aggregation under conditions that either promote or suppress the growth of gOs remain incompletely understood. Here we present a self-assembly model for amyloid fibril formation in the presence and absence of early stage off-pathway aggregates, driven by our experimental results on hen egg white lysozyme (HewL) and beta amyloid (A?) aggregation. The model reproduces a range of experimental observations including the sharp boundary in the protein concentration above which the self-assembly of gOs occurs. This is possible when both primary and secondary RFs nucleation rates are allowed to have a nonlinear dependence on initial protein concentration, hinting toward more complex prenucleation and RFs assembly scenarios. Moreover, analysis of RFs lag period in the presence and absence of gOs indicates that these off-pathway aggregates have an inhibitory effect on RFs nucleation. Finally, we incorporate the effect of an A? binding protein on the aggregation process in the model that allows us to identify the most suitable solution conditions for suppressing gOs and RFs formation.
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Project description:Abstracts: Adequate intakes of fat-soluble vitamins are essential to support the growth and development of the foetus, the neonate, and the young child. By means of an online self-administered frequency questionnaire, this study aimed to evaluate the intake of vitamins A, D, E, and K in Belgian infants (n = 455), toddlers (n = 265), pregnant women (n = 161), and lactating women (n = 165). The contribution of foods, fortified foods, and supplements on the total intake was quantified. 5% of toddlers, 16% of pregnant women, and 35% of lactating women had an inadequate vitamin A intake. Conversely, excessive vitamin A intakes were associated with consumption of liver (products). Furthermore, 22% of infants were at risk for inadequate vitamin D intake due to the lack of prophylaxis, while consumption of highly dosed supplements posed a risk for excessive intakes in 6%-26% of infants. Vitamin D intake in pregnant women and lactating women was inadequate (median of 51%, respectively, 60% of the adequate intake). In all groups, the risk for inadequate intake of vitamin E and K was low. Contribution of fortified foods to vitamin A, D, E, and K intake was minor, except in toddlers. National fortification strategies should be investigated as an alternative or additional strategy to prevent vitamin D and A deficiency. There is a need to revise and set uniform supplement recommendations. Finally, non-users of vitamin D prophylaxis need to be identified for targeted treatment.
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Project description:Understanding of the driving forces of protein folding is a complex challenge because different types of interactions play a varying role. To investigate the role of hydrogen bonding involving the backbone, the effect of thio substitutions in a protein, hen egg white lysozyme (HEWL), was investigated through molecular dynamics simulations of native as well as partly (only residues in loops) and fully thionated HEWL using the GROMOS 54A7 force field. The results of the three simulations show that the structural properties of fully thionated HEWL clearly differ from those of the native protein, while for partly thionated HEWL they only changed slightly compared with native HEWL. The analysis of the torsional-angle distributions and hydrogen bonds in the backbone suggests that the ?-helical segments of native HEWL tend to show a propensity to convert to 3(10)-helical geometry in fully thionated HEWL. A comparison of the simulated quantities with experimental NMR data such as nuclear overhauser effect (NOE) atom-atom distance bounds and (3)J((H)(N)(H)(?))-couplings measured for native HEWL illustrates that the information content of these quantities with respect to the structural changes induced by thionation of the protein backbone is rather limited.
| S-EPMC3537236 | biostudies-literature
Project description:Crystal structures of hen egg-white lysozyme (HEWL) determined under pressures ranging from ambient pressure to 950 MPa are presented. From 0.1 to 710 MPa, the molecular and internal cavity volumes are monotonically compressed. However, from 710 to 890 MPa the internal cavity volume remains almost constant. Moreover, as the pressure increases to 950 MPa, the tetragonal crystal of HEWL undergoes a phase transition from P43212 to P43. Under high pressure, the crystal structure of the enzyme undergoes several local and global changes accompanied by changes in hydration structure. For example, water molecules penetrate into an internal cavity neighbouring the active site and induce an alternate conformation of one of the catalytic residues, Glu35. These phenomena have not been detected by conventional X-ray crystal structure analysis and might play an important role in the catalytic activity of HEWL.
| S-EPMC4388261 | biostudies-literature
Project description:This study evaluates the application of eco-friendly deep eutectic solvents (DESs) in the extraction of phenolic antioxidants from dogbane leaf-tea (DLT). The results showed DESs with lower viscosity allowed an efficient extraction of significantly higher contents of total phenolics or flavonoids. An innovative and high-efficient solvent, choline chloride-levulinic acid (ChCl-LevA), was screened and used in ultrasonic-assisted extraction (UAE) of phenolic compounds from DLT. According to full factorial design experimental results, total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity, and anti-α-glucosidase activity (α-GIA) of the DLT extracts were simultaneously optimized by response surface methodology. Sonication temperature and water content in ChCl-LevA were found to be the major factors affecting the TPC, TFC, antioxidant activity, and α-GIA of DLT extracts. Under the optimum parameters (water content in ChCl-LevA was 45%, sonication temperature was 50 °C, and extraction time was 30 min), the measured results for all the responses were obtained as follows: TPC-91.38 ± 7.20 mg GAE/g DW, TFC-84.12 ± 3.47 mg RE/g DW, ABTS+-492 ± 7.33 mmol TE/g DW, FRAP-6235 ± 121 μmol Fe(II)/g DW and α-GIA-230 ± 7.59 mmol AE/g DW, which were consistent with the predicted values. In addition, strongly significant positive correlations were observed between TPC/TFC and bio-activities of the DLT extracts. HPLC results indicated high contents of (-)-epigallocatechin (4272 ± 84.86 μg/g DW), catechin (5268 ± 24.53 μg/g DW), isoquercitrin (3500 ± 86.07 μg/g DW), kaempferol 3-O-rutinoside (3717 ± 97.71 μg/g DW), and protocatechuic acid (644 ± 1.65 μg/g DW) were observed in the DLT extracts. In contrast to other extraction methods, ChCl-LevA-based UAE yielded higher TPC, TFC, individual phenolic contents, stronger antioxidant activity, and α-GIA. Scanning electron microscope (SEM) analysis further confirmed that ChCl-LevA-based UAE enhanced the disruption of cell wall structure, thereby making more phenolic antioxidants released from DLT. In short, ChCl-LevA-based UAE was confirmed to be an innovative and high-efficient method for extraction of phenolic antioxidants from DLT. Dogbane leaves can be considered as a good tea source rich in natural antioxidants.
| S-EPMC8620010 | biostudies-literature
Project description:Protein aggregation with the concomitant formation of amyloid fibrils is related to several neurodegenerative diseases, but also to non-neuropathic amyloidogenic diseases and non-neurophatic systemic amyloidosis. Lysozyme is the protein involved in the latter, and it is widely used as a model system to study the mechanisms underlying fibril formation and its inhibition. Several phenolic compounds have been reported as inhibitors of fibril formation. However, the anti-aggregating capacity of other heteroaromatic compounds has not been studied in any depth. We have screened the capacity of eleven different hydroxypyridines to affect the acid-induced fibrillization of hen lysozyme. Although most of the tested hydroxypyridines alter the fibrillation kinetics of HEWL, only 3-hydroxy-2-methylpyridine, 3-hydroxy-6-methylpyridine and 3-hydroxy-2,6-dimethylpyridine completely abolish fibril formation. Different biophysical techniques and several theoretical approaches are combined to elucidate their mechanism of action. O-methylated 3-hydroxypyridines bind non-cooperatively to two distinct but amyloidogenic regions of monomeric lysozyme. This stabilises the protein structure, as evidenced by enhanced thermal stability, and results in the inhibition of the conformational transition that precedes fibril assembly. Our results point to o-methylated 3-hydroxypyridines as a promising molecular scaffold for the future development of novel fibrillization inhibitors.
| S-EPMC4500996 | biostudies-literature
Project description:Long-term and graded dose of astaxanthin supplementation in laying hen's diet was assessed for egg fortification. Five groups of laying hens with 8 replications each were fed for 24 wk with diet supplemented astaxanthin at 0 mg/kg (control), 7.1 mg/kg, 14.2 mg/kg, 21.3 mg/kg, and 42.6 mg/kg (Basal, A7, A14, A21, and A42, respectively). The performance of laying hens, egg quality, astaxanthin concentration as well as conversion efficiency and geometric isomers proportion in yolks were assessed on wk 8 and 24. One-way analysis of variance (ANOVA) and linear and quadratic regression analyses were used to evaluate the dose effect. In parallel, the Student's t test compared the values between wk 8 and wk 24 of test within a group. Overall, the results revealed that neither production performance nor egg physical quality was affected by astaxanthin dose level and feeding duration. Following the supplementation dose, the redness of yolks (a*) increased (P < 0.001). But, the a* score in A42 (23.48) was just 3-folds the a* score in A7 (8.89). Concentration of astaxanthin in eggs was dose-level dependent showing a linear relationship (P < 0.001) with a slight declination observed in all groups on wk 24 compared to wk 8. The deposition rate of astaxanthin into egg yolk was higher in A21 and A42. The proportion of geometric isomers in egg yolk were not affected by the feeding duration. As the supplementation dose increased, all-trans isomer proportion gradually decreased in the egg yolk, while 13-cis isomer proportion rose. It was concluded that astaxanthin is an efficient carotenoid for egg fortification, which can be supplemented in diet up to 42.6 mg/kg for 24 wk without compromising the performance of laying hens or physical quality of eggs. This appreciably affects the egg yolk color and confers a better accumulation of total astaxanthin and cis isomers into eggs as the supplementation dose increases.
| S-EPMC8348582 | biostudies-literature
Project description:Stabilization of a protein using cavity-filling strategy has hardly been successful because of unfavorable van der Waals contacts. We succeeded in stabilizing lysozymes by cavity-filling mutations. The mutations were checked by a simple energy minimization in advance. It was shown clearly that the sum of free energy change caused by the hydrophobicity and the cavity size was correlated very well with protein stability. We also considered the aromatic-aromatic interaction. It is reconfirmed that the cavity-filling mutation in a hydrophobic core is a very useful method to stabilize a protein when the mutation candidate is selected carefully.
| S-EPMC2373952 | biostudies-literature
Project description:Glycation causes severe damage to protein structure that could lead to amyloid formation in special cases. Here in this report, we have shown for the first time that hen egg white lysozyme (HEWL) does not undergo amyloid formation even after prolonged glycation in the presence of D-glucose, D-fructose and D-ribose. Cross-linked oligomers were formed in all the cases and ribose was found to be the most potent among the three sugars. Ribose mediated oligomers, however, exhibit Thioflavin T binding properties although microscopic images clearly show amorphous and globular morphology of the aggregates. Our study demonstrates that the structural damage of hen egg white lysozyme due to glycation generates unstructured aggregates.
| S-EPMC3774808 | biostudies-literature
Project description:Injectable hydrogels based on synthetic peptides have shown great promise in many biomedical applications. Yet, the high cost generally associated with synthetic peptides hinders the practical use of such peptide-based injectable hydrogel. To overcome this drawback, here, we propose to use the peptides from hydrolyzed low-cost natural protein as an economical and convenient peptide source to prepare an injectable hydrogel. We demonstrate the effectiveness of this alternative strategy using hen egg white lysozyme (HEWL) as an example. We used the peptide fragments from hydrolyzed HEWL as the gelator, and the magnesium ion as the performance enhancer to prepare the injectable hydrogel. We showed that the hydrogel is an amyloid gel as it was formed by a dense network of amyloid fibrils. We also showed that the hydrogel possesses a thixotropic property and displays a low cytotoxicity. The hydrolysis extent of HEWL was found to be a critical factor that influences the performance of the hydrogel. A fluorescence assay based on 8-anilinonaphthalene-1-sulfonic acid was proposed as a mean to precisely and conveniently control the hydrolysis extent of HEWL to enable the best injectability performance. At last, using doxorubicin as a model compound, we explored the potential of this amyloid-based hydrogel as an injectable drug carrier.
| S-EPMC6648635 | biostudies-literature