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1.
The cyanobacterium Spirulina platensis is a source of pigments, such as phycocyanin, which is used in the food, cosmetic and pharmaceutical industries. The thermal degradation kinetics of the liquid extract at pH values of 5, 6 and 7 was studied, evaluating its stability between 50 and 65 °C. The kinetic model was assumed and validated as being of the first order. Between 50 and 55 °C the extract was more stable at pH 6 and between 57 and 65 °C at pH 5, but was shown to be increasingly unstable at pH 7 as the temperature of the treatment increased. The addition of sorbitol between 10 and 50% (w/w) in the treatment at 62 °C for 30 min increased the half-life values of the phycocyanin extract, proving that its de-colorization was related to degradation of the protein chain. 相似文献
2.
The effluent from the biogas process was tested as a nutrient source during cultivation of the protein-rich and edible microalgae Spirulina (Arthrospira platensis) and compared with conventional Spirulina medium. Equal biomass production was observed until late exponential phase and no significant differences could be observed between the treatments in protein amount, amino acid composition, and total lipid concentration. The concentration of the pigment phycocyanin differed significantly between Spirulina medium and the effluent-based medium (63.3 ± 11.7 and 86.2 ± 1.9 mg g−1, respectively). Slightly higher concentrations of saturated fatty acids, mainly palmitic acid, were observed in the biomass produced in Spirulina medium than in that produced in the effluent-based medium. In the biomass produced in the effluent-based medium, the cadmium concentration was 0.07 ± 0.05 mg kg−1 of dry weight, whereas it was below the detection limit in the biomass produced in Spirulina medium. There is a need to identify new food and feed resources and a possible future scenario is to integrate Spirulina production into the biogas plant for protein production as it contains more than 60% of protein on dry weight basis. In that scenario, it is important to control heavy metal concentrations in the biogas slurry fed to Spirulina. 相似文献
3.
The influence of actively/passively encapsulated oleuropein on DPPC liposomes thermal and structural properties, and its antioxidant capacity against lipid peroxidation were investigated. Also, an oleuropein-rich olive leaf extract was encapsulated in soy phosphatidylcholine (PL-90 g) and incorporated in model and commercial drinks. Oleuropein induced a concentration-dependent broadening and splitting of the gel-to-liquid phase transition temperature. Fluorescence measurements revealed a fluidizing effect on liposomes below their gel-to-liquid phase transition temperature, and a higher lipid ordering above, especially to active encapsulation. Oleuropein also showed an antioxidant effect against lipid peroxidation in PL-90 g liposomes. PL-90 g Liposomes with olive leaf extract showed a mean diameter of 405 ± 4 nm and oleuropein encapsulation efficiency of 34% and delayed oleuropein degradation at pH 2.0 and 2.8 model drinks. In conclusion, greater effects were observed on the structure and fluidity of DPPC liposomes when oleuropein was actively encapsulated, while its incorporation into acidic foods in encapsulated form could enhance its stability. 相似文献
4.
Compost extract or “compost tea” is a liquid extract of compost obtained by mixing compost and water for a defined period
of time. Compost tea contains nutrients and a range of different organisms and is applied to the soil or directly to plants
with the principal aim of suppressing certain plant diseases. In addition, the application of compost tea supplies nutrients
and organic matter to the soil. Thermal analysis and Fourier transform infrared spectroscopy (FTIR) are two widely applied
analytical techniques for establishing the stability of compost, and although numerous studies have evaluated the capacity
of compost tea to suppress plant diseases, there are no studies employing these techniques to characterize compost-tea. For
the present study, 12 compost extracts were produced under varying conditions in a purpose-built reactor. Two different composts,
an stable compost produced from manure and an unstable compost produced from municipal solid waste, respectively, two aeration
systems (aerated and non-aerated extracts) and three temperatures (10, 20 and 30°C) were used in these experiments. The extracts
were freeze-dried and subsequently analysed, together with the two composts, by means of FTIR and thermal analysis. Extracts
produced from high stability compost, independently of the conditions of aeration and temperature, showed very similar results.
In contrast, differences among extracts produced from the unstable compost were more noticeable. However, the different conditions
of aeration and temperature during the production of the extracts only explained partially these differences, since the transformations
undergone by compost over the 3 months that the experiments lasted were also reflected in the composition of the extracts.
In spite of everything, extraction process favoured the degradation of easily oxidizable organic matter, which was more abundant
in unstable compost. This degradation was more intense for non-aerated processes, probably due to the longer duration of these
(10 days) with respect to aerated extractions (2 days). The effect of temperature was not clear in these experiments, although
high temperatures could increase micro organism activity and consequently favour the degradation of easily oxidizable organic
matter. 相似文献
5.
Compared to commonly applied wet and dry heating procedures, a combination of electrospinning and heat treatment can facilitate glycation of proteins with reducing polysaccharides. This study investigates how the amount of reducing carbonyl groups (i.e. dextrose equivalent, DE) of different maltodextrins influences electrospinnability and subsequent glycation in blends with pea protein isolate (PPI). In the first step of the study, maltodextrin-PPI dispersions were electrospun. The concentrations of PPI and maltodextrin DE 2 were kept constant in the aqueous spinning dispersion. The addition of 0.05 or 0.1 g/mL maltodextrin DE 12 or 21 slightly affected the electrical conductivity and dynamic viscosity of the spinning dispersions, however, fiber production rate and morphology were dominated by the presence of maltodextrin DE 2 (0.8 g/mL). In the second step of the study, fibers were heated (60 °C, 75% rel. Humidity, 0–24 h). SDS-PAGE analysis and the measurement of free amino groups confirmed the covalent attachment of maltodextrin carbonyl groups to free amino groups of PPI. The fastest glycation and the lowest relative amount of free amino groups (49.70 ± 6.54%) after 24 h heating was measured for the fibers with the highest amount of reducing carbonyl groups. The fibers with the lowest amount of reducing carbonyl groups showed no significant (p < 0.05) decrease of free amino groups after heat treatment. The results suggest that within the boundaries of electrospinnability, the degree of glycation can be adjusted by varying the amount of reducing carbonyl groups in the fibers. 相似文献
6.
Mollusc shells represent excellent systems for the preservation and retrieval of genuine biomolecules from archaeological or palaeontological samples. As a consequence, the post-mortem breakdown of intracrystalline mollusc shell proteins has been extensively investigated, particularly with regard to its potential use as a “molecular clock” for geochronological applications. But despite seventy years of ancient protein research, the fundamental aspects of diagenesis-induced changes to protein structures and sequences remain elusive. In this study we investigate the degradation of intracrystalline proteins by performing artificial degradation experiments on the shell of the thorny oyster, Spondylus gaederopus, which is particularly important for archaeological research. We used immunochemistry and tandem mass tag (TMT) quantitative proteomics to simultaneously track patterns of structural loss and of peptide bond hydrolysis.Powdered and bleached shell samples were heated in water at four different temperatures (80, 95, 110, 140 °C) for different time durations. The structural loss of carbohydrate and protein groups was investigated by immunochemical techniques (ELLA and ELISA) and peptide bond hydrolysis was studied by tracking the changes in protein/peptide relative abundances over time using TMT quantitative proteomics. We find that heating does not induce instant organic matrix decay, but first facilitates the uncoiling of cross-linked structures, thus improving matrix detection. We calculated apparent activation energies of structural loss: E a (carbohydrate groups) = 104.7 kJ/mol, E a (protein epitopes) = 104.4 kJ/mol, which suggests that secondary matrix structure degradation may proceed simultaneously with protein hydrolysis. While prolonged heating at 110 °C (10 days) results in complete loss of the structural signal, surviving peptide sequences were still observed. Eight hydrolysis-prone peptide bonds were identified in the top scoring shell sequence, the uncharacterised protein LOC117318053 from Pecten maximus. Interestingly, these were not the expected “weak” bonds based on published theoretical stabilities calculated for peptides in solution. This further confirms that intracrystalline protein degradation patterns are complex and that the overall microchemical environment plays an active role in protein stability. Our TMT approach represents a major stepping stone towards developing a model for studying protein diagenesis in biomineralised systems. 相似文献
7.
The recent challenge in orally disintegrating tablets (ODT) manufacturing encompasses the compromise between instantaneous
disintegration, sufficient hardness, and standard processing equipment. The current investigation constitutes one attempt
to fulfill this challenge. Maltodextrin, in the present work, was utilized as a novel excipient to prepare ODT of meclizine.
Tablets were prepared by both direct compression and wet granulation techniques. The effect of maltodextrin concentrations
on ODT characteristics—manifested as hardness and disintegration time—was studied. The effect of conditioning (40°C and 75%
relative humidity) as a post-compression treatment on ODT characteristics was also assessed. Furthermore, maltodextrin-pronounced
hardening effect was investigated using differential scanning calorimetry (DSC) and X-ray analysis. Results revealed that
in both techniques, rapid disintegration (30–40 s) would be achieved on the cost of tablet hardness (about 1 kg). Post-compression
conditioning of tablets resulted in an increase in hardness (3 kg), while keeping rapid disintegration (30–40 s) according
to guidance of the FDA for ODT. However, direct compression-conditioning technique exhibited drawbacks of long conditioning
time and appearance of the so-called patch effect. These problems were, yet, absent in wet granulation-conditioning technique.
DSC and X-ray analysis suggested involvement of glass-elastic deformation in maltodextrin hardening effect. High-performance
liquid chromatography analysis of meclizine ODT suggested no degradation of the drug by the applied conditions of temperature
and humidity. Overall results proposed that maltodextrin is a promising saccharide for production of ODT with accepted hardness-disintegration
time compromise, utilizing standard processing equipment and phenomena of phase transition. 相似文献
8.
Development studies were performed to design a pharmaceutical composition that allows the stabilization of a parenteral rhEGF formulation in a lyophilized dosage form. Unannealed and annealed drying protocols were tested for excipients screening. Freeze-dry microscopy was used as criterion for excipients and formulation selection; as well as to define freeze-drying parameters. Excipients screening were evaluated through their effect on freeze-drying recovery and dried product stability at 50 °C by using a comprehensive set of analytical techniques assessing the chemical stability, protein conformation and bioactivity. The highest stability of rhEGF during freeze-drying was achieved by the addition of sucrose or trehalose. After storing the dried product at 50 °C, the highest stability was achieved by the addition of dextran, sucrose, trehalose or raffinose. The selected formulation mixture of sucrose and dextran could prevent protein degradation during the freeze-drying and delivery processes. The degradation rate assessed by RP-HPLC could decrease 100 times at 37 °C and 70 times at 50 °C in dried with respect to aqueous formulation. These results indicate that the freeze-dried formulation represents an appropriate technical solution for stabilizing rhEGF. 相似文献
9.
Nodal segments (4 ± 1 mm long) of Hibiscus moscheutos (hardy hibiscus) were excised from in vitro proliferating microshoots and utilized to evaluate initial factors involved in
bulk alginate encapsulation. The factors evaluated were; storage vessel type, volume and multiple rinse effects of CaCl 2 solutions, and sodium alginate concentrations (2.5, 2.75, 3.0 or 3.25%) for bulk alginate encapsulation. Results indicate
that vessels utilized for bulk alginate encapsulation should have a lower base area ( L × W) to height ratio to reduce the amount of alginate matrix shrinkage resulting in exposure of nodal segments. Increased volumes
and multiple 50 mM CaCl 2 solution rinses did not have an effect on alginate solidification. Shoot length, root number, and root length significantly
decreased in a linear manner from nodal explants stored for 4 weeks with increasing concentrations of sodium alginate. This
research suggests an innovative technique for alginate encapsulation of H. moscheutos utilizing bulk methods as an alternative to single bead alginate encapsulation. 相似文献
10.
Probiotic supplements can contribute to maintaining health and ameliorating various disease symptoms. Probiotics can be delivered in many forms with crucial differences in their survival during gastrointestinal (GI) passage. Previously, a novel encapsulation, Probiotic Pearls™ Acidophilus, Integrative Therapeutics, LLC, USA (Pearls), was shown to increase survival in vitro after exposure to gastric conditions. Here, we compare fecal recovery in human volunteers consuming Pearls or a conventional hard-shelled gelatin capsule. We performed a randomized double-blinded, two-armed trial, with six healthy subjects in each 12-day study arm. In fecal samples collected at baseline, twice during the intervention period, and after washout, we compared colony counts between the two encapsulation methods. The identity of the colonies was confirmed by colony morphology, strain-specific PCR, and 16S rRNA gene sequencing. We further performed a comprehensive 16S rRNA gene sequencing-based analysis to identify differential effects on overall microbiota composition. We detected an average log increase in bifidobacteria of 0.152 cfu/g with gelatin and 0.651 cfu/g with Pearls capsules (p > 0.05). Total lactobacilli counts increased in both groups with no difference between the groups. However, the supplemented Lactobacillus acidophilus NCFM decreased to baseline levels within 7 days after end of supplementation with gelatin capsules while 3.11 log cfu/g higher counts compared to baseline (p = 0.05) remained for Pearls. Targeted qPCR largely confirmed the trends observed by viable plate counts. Protecting the probiotic strains by Pearls encapsulation results in higher recovery rates of the supplemented lactobacilli and bifidobacteria in fecal samples and increased persistence, suggesting an improved survival and viability that might increase efficacy towards achieving desired health benefits. 相似文献
11.
Equilibrium phase diagrams of the ι-carrageenan/maltodextrin/water system have been established at potassium chloride (KCl)
concentrations of 0.1, 0.2, and 0.3 M and 80, 85 and 90°C. All pseudo-binary phase diagrams of ι-carrageenan/maltodextrin
mixtures suggested classic segregative phase separation. The binodal was heavily skewed toward the maltodextrin axis. The
high asymmetry of the ι-carrageenan/maltodextrin/water phase diagram determined by the phase-volume-ratio method was consistent
with the compositional analysis of phase-separated ι-carrageenan/maltodextrin samples and can be explained in terms of the
Flory–Huggins interaction parameter, reflecting a higher water-binding ability of the charged ι-carrageenan than neutral maltodextrin.
Increasing the concentration of ι-carrageenan-gel-promoting KCl from 0.1 to 0.3 M at 80°C enlarged the two-phase domain, whereas
increasing temperature from 80 to 90°C at 0.3 M KCl enhanced biopolymer compatibility. The effects of salt concentration and
temperature have been related to the differences in the Flory–Huggins interaction parameters of the two biopolymers with water
as well as the helix formation of ι-carrageenan in the presence of KCl through the changes in the slopes of tie lines of phase-separated
samples.
相似文献
12.
The aim of this study was to evaluate the effects of preparation method and the type of surfactant on the properties of cephalexin
(CPX) microspheres in order to obtain delivery systems suitable for the treatment of dairy mastitis. Microspheres were obtained
using various preparation conditions and their physicochemical characteristics such as size, loading efficiency, morphology,
and drug crystallinity were investigated. Antibacterial activity of microspheres from the optimum preparation condition was
also studied. CPX microspheres were prepared by two different W/O/W emulsion solvent evaporation methods using PLGA as a matrix
forming polymer. Several types of surfactants including nonionic, cationic, and anionic at different concentrations were used
for preparation of the particles. The type and concentration of surfactant did neither affect the size nor morphology of the
microspheres but showed a pronounced effect on the CPX encapsulation efficiency. It was found that Tween 80 showed the highest
drug encapsulation efficiency (66.5%). Results from X-ray diffraction diffractograms and differential scanning calorimetry
thermograms indicated that CPX entrapped in these microparticles was amorphous. Assessment of antibacterial activity showed
that the obtained CPX microspheres exhibited good inhibition with minimum inhibitory concentration and minimum bactericidal
concentration values of 128 μg/mL and 2,048 mg/mL against Staphylococcus aureus ATCC 25923, 512 μg/mL and 4,096 mg/mL against Escherichia coli ATCC 25922, respectively. 相似文献
13.
The targeted delivery of therapeutic peptide by nanocarriers systems requires the knowledge of interactions of nanomaterials with the biological environment, peptide release, and stability of therapeutic peptides. Therapeutic application of nanoencapsulated peptides are increasing exponentially and >1000 peptides in nanoencapsulated form are in different clinical/trial phase. This review covers current scenario of therapeutic protein and peptides encapsulation on polymer to metallic nanocarriers including methods of protein encapsulation, peptide bioconjugation on nanoparticles, stability enhancement of encapsulated proteins and its biomedical applications. 相似文献
14.
For quinoline-denitrifying degradation, very few researches focused on shortcut denitrification process and its bacterial community characteristics. In this study, complete and shortcut denitrification systems were constructed simultaneously for quinoline degradation. By calculation, specific quinoline removal rates were 0.905 and 1.123 g/(gVSS d), respectively, in the complete and shortcut systems, and the latter was 1.24 times of the former. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE), high-throughput sequencing, and quantitative PCR (qPCR) techniques based on 16S rRNA were jointly applied to compare microbial community structures of two systems. Many denitrifying bacteria phyla, classes, and genera were detected in the two systems. Phylum Proteobacteria, Class Gammaproteobacteria, and Genus Alicycliphilus denitrificans were the dominant contributors for quinoline-denitrifying degradation. In the shortcut denitrification system, main and specific strains playing crucial roles were more; the species richness and the total abundance of functional genes (narG, nirS, nirK, and nosZ) were higher compared with the complete denitrification system. It could be supposed that inorganic-nitrogen reductase activity of bacterial community was stronger in the shortcut denitrification system, which was the intrinsic reason to result in higher denitrification rate. 相似文献
15.
In the present study, the efficacy of Basella alba L. (commonly known as Indian spinach) mucilage ( BAM) was explored for the first time towards the encapsulation of hydrophobic antioxidants. The hydrophobic antioxidants were encapsulated into the BAM matrix by modified non-solvent precipitation method and the encapsulated systems were fully characterized on the basis of TGA, DLS and SEM data. Interactions between the components of BAM matrix and the hydrophobic antioxidants are the key factors for the efficient encapsulation process. These interactions were studied with the help of spectroscopic techniques. The BAM-encapsulated antioxidants showed high pH and photo-stability. Moreover, the hydrophobic antioxidants after their encapsulation in the BAM matrix showed enhanced water solubility and hence, bioactivity in aqueous medium. Thus, BAM may be explored in future as an ideal candidate for the encapsulation and delivery of the hydrophobic bioactive compounds in cellular medium. 相似文献
16.
Granulocyte–macrophage colony-stimulating factor (GM-CSF) is a cytokine used in the treatment of serious conditions resulting
from chemotherapy and bone marrow transplantation such as neutropenia and aplastic anemia. Despite these effects, GM-CSF has
a very short biological half-life, and it requires frequent injection during the treatment. Therefore, the cytokine production
is possible in the body with plasmid-encoded GM-CSF (pGM-CSF) coding for cytokine administered to the body. However, the selection
of the proper delivery system for the plasmid is important. In this study, two different delivery systems, encapsulated plasmid
such as fucoidan–chitosan (fucosphere) and chitosan microspheres, were prepared and the particle physicochemical properties
evaluated. Fucospheres and chitosan microspheres size ranges are 151–401 and 376–681 nm. The zeta potential values of the
microspheres were changed between 8.3–17.1 mV (fucosphere) and +21.9–28.9 mV (chitosan microspheres). The encapsulation capacity
of fucospheres changed between 84.2% and 94.7% depending on the chitosan molecular weight used in the formulation. In vitro plasmid DNA release from both delivery systems exhibited slower profiles of approximately 90–140 days. Integrity of released
samples was checked by agarose gel electrophoresis, and any additional band was not seen. All formulations were analyzed kinetically.
The calculated regression coefficients showed a higher r
2 value with zero-order kinetics. In conclusion, the characterizations of the microspheres can be modulated by changing the
formulation variables, and it can be concluded that fucospheres might be a potential carrier system for the controlled delivery
of GM-CSF encoding plasmid DNA. 相似文献
17.
The taste and flavor of spray-dried powdered products are the most important quality factors. In the present study, molecular encapsulation in cyclodextrin was applied to prevent the loss of a hydrophobic flavor compound (l-menthol) during the drying of a droplet. beta-Cyclodextrin appeared to be a better encapsulant for menthol than alpha- and gamma-cyclodextrin. The retention of menthol increased with increasing concentration of both cyclodextrin and maltodextrin. A simple mathematical model is proposed for estimating the flavor retention. The theoretical results by this model estimated well the final retention of menthol encapsulated in a blend of beta-cyclodextrin and maltodextrin. 相似文献
18.
The structural properties of collagen have been the subject of numerous studies over past decades, but with the arrival of new technologies, such as the atomic force microscope and related techniques, a new era of research has emerged. Using microthermal analysis, it is now possible to image samples as well as performing localized thermal measurements without damaging or destroying the sample itself. This technique was successfully applied to characterize the thermal response between native collagen fibrils and their denatured form, gelatin. Thermal transitions identified at (150 ± 10)°C and (220 ± 10)°C can be related to the process of gelatinization of the collagen fibrils, whereas at higher temperatures, both the gelatin and collagen samples underwent two-stage transitions with a common initial degradation temperature at (300 ± 10)°C and a secondary degradation temperature of (340 ± 10)°C for the collagen and of (420 ± 10)°C for the gelatin, respectively. The broadening and shift in the secondary degradation temperature was linked to the spread of thermal degradation within the gelatin and collagen fibrils matrix further away from the point of contact between probe and sample. Finally, similar measurements were performed inside a bone resorption lacuna, suggesting that microthermal analysis is a viable technique for investigating the thermomechanical response of collagen for in situ samples that would be, otherwise, too challenging or not possible using bulk techniques. 相似文献
19.
AbstractPulmonary lung targeting finds applications in drug delivery to the lung itself and to other body organs, via blood circulation following transfer across alveolar membranes. Understanding pulmonary drug delivery systems towards improving their efficacy needs identification of particle sizes of relevance and elucidation of links between suspension properties, techniques of atomisation and properties of the generated aerosols. This review article is focussed on understanding the elements of pulmonary drug delivery, specifically related to suspensions of small liposomes. Specific objectives of this review include (a) understanding aerosol particle deposition and absorption on pulmonary surface, (b) links between properties of aerosol generation and colloidal drug carriers used for drug encapsulation, and (c) investigation on the controlled properties of liposome aerosols generated using different atomisation techniques for efficacious aerosol therapy. 相似文献
20.
Embryogenic synseeds were prepared in Albizia lebbeck by encapsulating cotyledon stage somatic embryos derived from in vitro maintained embryogenic cultures in different types of Ca-alginate beads. The germination rate of somatic embryos was affected significantly by the bead type, matrix composition and germination substrate. A matrix made of 3% Na2-alginate complexed with 100 mM CaCl2·2H2O for a hardening period of 20 min provided uniform encapsulation of somatic embryo. Among different types of synseeds, type IIA, wherein somatic embryos encapsulated in a single layer of Ca-alginate matrix composed of MS medium supplemented with 2 g L?1 activated charcoal and 1.0 µM gibberellic acid (GA3) as reconstituted endosperm, was found to be the most efficient type having maximum germination rates (88.6?±?0.51%). Incorporation of GA3 in the alginate beads stimulated greater germination of somatic embryos as against GA3 supplementation in the germination substrate. Further, viability studies on short term cold (4 °C) storage of different types of embryogenic synseeds revealed that double layered synseeds (DLS) were found comparatively more robust to withstand longer storage durations than single layered synseeds as evident by greater germination rates of the former after 4–8 weeks of refrigerated storage. Also, the elevated levels of antioxidative enzymes (superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase) and leaf proline content in the plantlets derived from DLS reveals the possible role of alginate coatings in conferring alleviation to low temperature stress generated during different storage durations. Similar Inter simple sequence repeat profiles of embryogenic synseeds derived plantlets and mother tree nullifies the possible occurrence of somaclones, thereby establishing the efficacy of synseed technology for clonal propagation of A. lebbeck germplasm. 相似文献
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