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1.
Volcaniella eurihalina strain F2-7 synthesizes an exopolysaccharide named V2-7, primarily composed of glucose, mannose, and rhamnose. The effect of chemical and physical factors on solution viscosity was studied. The V2-7 EPS showed pseudoplastic behavior at concentrations over 0.5% w/v. Viscosity decreased with temperature, but the viscosity values were restored after cooling. Freeze-thawing treatment did not affect the rheological properties of its solutions. Addition of inorganic salts produced a diminution of viscosity. However, the most remarkable aspect of V2-7 EPS is the effect of pH on its solutions; it is able to form high viscosity solutions, like a gel, at low pH values even in the presence of inorganic salts. This property, not present in neutral and alkaline solutions, makes it potentially useful for various industrial applications.  相似文献   

2.
Cupuassu (Theobroma grandiflorum Schum.) is a popular Amazonian fruit because of its intense aroma and nutritional value, whose lipid fraction is alternatively used in cosmetics. To preserve active principles and ensure their controlled release, extract was microencapsulated by spray drying. Influence of spray-drying conditions on microencapsulation of cupuassu seed by-product extract was investigated according to a 33-Box Behnken factorial design, selecting inlet temperature, maltodextrin concentration and feed flowrate as independent variables, and total polyphenol and flavonoid contents, antiradical power, yields of drying and microencapsulation as responses. Fitting the results by second-order equations and modelling by Response Surface Methodology allowed predicting optimum conditions. Epicatechin and glycosylated quercetin were the major microencapsulated flavonoids. Microparticles showed satisfactory antiradical power and stability at 5 °C or under simulated gastrointestinal conditions, thus they may be used to formulate new foods or pharmaceuticals.  相似文献   

3.
This work reports for the first time the nutritional profile and antioxidant potential of the edible sea cucumber Holothuria arguinensis from the North-eastern Atlantic. H. arguinensis has high levels of protein, with the amino acids profile dominated by alanine, glycine and proline and low lysine/arginine ratios. Its carbohydrate and energetic contents are also low as well as the total lipid levels, although its lipid profile is rich in polyunsaturated fatty acids (PUFA), especially arachidonic, eicosapentaenoic and docosahexaenoic acids. In addition, H. arguinensis has high levels of calcium. The water and ethanol extracts show ability to scavenge free radicals and to chelate copper and iron ions. Our results indicate that H. arguinensis has a balanced nutritional quality suitable for human consumption. In addition, it contains compounds with antioxidant potential; thus its intake can contribute for a healthy and well-balanced diet.  相似文献   

4.
Plants have a potential to produce a large number of important metabolites such as pharmaceuticals, food additives, pigments, flavors, fragrances, and fine chemicals. Large-scale plant cell and tissue cultures for producing useful products has been considered an attractive alternative to whole plant extraction for obtaining valuable chemicals. In plant cell and tissue cultures, cell growth and metabolite production are influenced by nutritional and environmental conditions as well as physical properties of the culture system. To obtain a high growth rate of plant cell and tissue cultures, the culture tem. To obtain a high growth rate of plant cell and tissue cultures, the culture conditions should be maintained at an optimum level. We studied the relationship between inoculum conditions and the growth of Panax ginseng hairy root culture, and found that the growth rate varied with the inoculum conditions such as the number of root tips, the length of root tips, the part of root tips, and the inoculum size and age of hairy roots.  相似文献   

5.
Proanthocyanidins were separated for the first time from Cinnamomum longepaniculatum leaves. An experiment‐based extraction strategy was used to research the efficiency of an ultrasound‐assisted method for proanthocyanidins extraction. The Plackett–Burman design results revealed that the ultrasonication time, ultrasonic power and liquid/solid ratio were the most significant parameters among the six variables in the extraction process. Upon further optimization of the Box–Behnken design, the optimal conditions were obtained as follows: extraction temperature, 100°C; ethanol concentration, 70%; pH 5; ultrasonication power, 660 W; ultrasonication time, 44 min; liquid/solid ratio, 20 mL/g. Under the obtained conditions, the extraction yield of the proanthocyanidins using the ultrasonic‐assisted method was 7.88 ± 0.21 mg/g, which is higher than that obtained using traditional methods. The phloroglucinolysis products of the proanthocyanidins, including the terminal units and derivatives from the extension units, were tentatively identified using a liquid chromatography with tandem mass spectrometry analysis. Cinnamomum longepaniculatum proanthocyanidins have promising antioxidant and anti‐nutritional properties. In summary, an ultrasound‐assisted method in combination with a response surface experimental design is an efficient methodology for the sufficient isolation of proanthocyanidins from Cinnamomum longepaniculatum leaves, and this method could be used for the separation of other bioactive compounds.  相似文献   

6.
Food is a complex matter, literally. From production to functionalization, from nutritional quality engineering to predicting effects on health, the interest in finding an efficient physicochemical characterization of food has boomed in recent years. The sheer complexity of characterizing food and its interaction with the human organism has however made the use of data driven approaches in modeling a necessity. High-throughput techniques, such as nuclear magnetic resonance (NMR) spectroscopy, are well suited for omics data production and, coupled with machine learning, are paving a promising way of modeling food–human interaction. The foodomics approach sets the framework for omic data integration in food studies, in which NMR experiments play a key role. NMR data can be used to assess nutritional qualities of food, helping the design of functional and sustainable sources of nutrients; detect biomarkers of intake and study how they impact the metabolism of different individuals; study the kinetics of compounds in foods or their by-products to detect pathological conditions; and improve the efficiency of in silico models of the metabolic network.  相似文献   

7.
The Pichia pastoris clone producing streptokinase (SK) was optimized for its nutritional requirements to improve intracellular expression using statistical experimental designs and response surface methodology. The skc gene was ligated downstream of the native glyceraldehyde 3-phosphate dehydrogenase promoter and cloned in P. pastoris. Toxicity to the host was not observed by SK expression using YPD medium. The transformant producing SK at level of 1,120 IU/ml was selected, and the medium composition was investigated with the aim of achieving high expression levels. The effect of various carbon and nitrogen sources on SK production was tested by using Plackett–Burman statistical design and it was found that dextrose and peptone are the effective carbon and nitrogen sources among all the tested. The optimum conditions of selected production medium parameters were predicted using response surface methodology and the maximum predicted SK production of 2,136.23 IU/ml could be achieved with the production medium conditions of dextrose (x1), 2.90%; peptone (x2), 2.49%; pH, 7.2 (x3), and temperature, 30.4 (x4). Validation studies showed a 95% increase in SK production as compared to that before optimization at 2,089 IU/ml. SK produced by constitutive expression was found to be functionally active by plasminogen activation assay and fibrin clot lysis assay. The current recombinant expression system and medium composition may enable maximum production of recombinant streptokinase at bioreactor level.  相似文献   

8.
Summary: In this study, the rheological behaviors of media fermented by two Aureobasidium pullulans strains (IOC 3467 and IOC 3011) were evaluated in different nutritional conditions. The media consisted of crystal sugar (sucrose), as the main carbon source, and different nitrogen sources (ammonium sulfate, sodium nitrate, ammonium nitrate, urea or residual brewery yeast - RBY). Viscosity measurements were performed on cell-free supernatants, from 48-hour fermentation assays, at 25 °C. Shear rates ranged between 0.1000 and 500 s−1. All samples showed pseudoplastic behavior. Nevertheless, the viscosimetric profile of each one varied according to the nitrogen source, its concentration and the strain used. The maximum viscosity of 0.06 Pa.s. was achieved at 15.6 s−1 for IOC 3011 strain grown on RBY as nitrogen source.  相似文献   

9.
In human nutrition research, nuclear analytical techniques, particularly neutron activation analysis (NAA), are used mainly for thein vitro study of trace elements. According to work sponsored by the IAEA, up to 15 trace elements and 5 minor elements of nutritional interest may be determined in biological materials by NAA with good accuracy and precision. A programme is described in which NAA was used for the determination of 14 trace elements and one minor element in human milk. NAA also plays an important role in the certification of reference materials for nutritional studies.  相似文献   

10.
Although most fermentation ethanol is currently produced in traditional batch processes with yeast, the ethanologenic bacteriumZymomonas mobilis is recognized as an alternative process organism for fuel alcohol production. Different strategies for improving the productivity of ethanol fermentations are reviewed. In batch and open-type continuous fermentations the advantage of replacing yeast byZymomonas relates principally to the 10% higher fermentation efficiency (product yield), whereas in high cell density, closed-type continuous systems (operating with cell recycle or retention) the superior kinetic properties ofZymomonas can be exploited to affect about a five-fold improvement in volumetric productivity. Unlike yeast, the rate of energy supply (conversion of glucose to ethanol) inZymomonas is not strictly regulated by the energy demand and a nongrowing culture exhibits a maintenance energy coefficient that is at least 25 times higher than yeast. As an alternative to process improvement through genetic engineering of the process organism this investigation has taken a biochemical and physiological approach to increasing the kinetic performance ofZ. mobilis through manipulation and control of the chemical environment. Energetically “uncoupled” phenotypes with markedly increased specific rates of ethanol production were generated under conditions of nutritional limitation (nitrogen, phosphate, or potassium) in steady-state continuous culture. The pH was shown to influence energy coupling inZymomonas affecting the maintenance coefficient (m e ) rather than the max growth yield coefficient (Y x sάx ). Whereas the pH for optimal growth ofZ. mobilis (ATCC 29191) in a complex medium was 6.0–6.5, the specific rate of ethanol production in continuous fermentations was maximal in the range 4.0–4.5. Fermentation conditions are specified for maximizing the specific productivity of aZymomonas-based continuous ethanol fermentation where the potential exists for improving the volumetric productivity in dense culture fermentations with an associated 35–40% reduction in capital costs of fermentation equipment and an estimated savings of 10–15% on cost of product recovery (distillation), and 3–7% on overall production costs based on the projected use of inexpensive feedstocks.  相似文献   

11.
Emulsion forms a major part of many processed food formulations. During the past few decades, the physico-chemical properties of oil-in-water emulsions under various food processing conditions have been extensively studied. However, over the recent years, interest has turned to understanding the behaviour of emulsions during consumption, i.e. physiological processing. In general, on ingestion, an emulsion is exposed to a relatively narrow range of physical (e.g. shear and temperature) and biochemical (e.g. dilution, pH, pepsin, pancreatin, mucins and bile salts) environments as it passes through the mouth into the stomach and then the intestines. There is currently limited knowledge of the physico-chemical and structural changes, which an emulsion may undergo when it passes through the physiologically active regime. A better understanding of the gastro-intestinal processing of emulsions would allow manipulation of physico-chemical and interfacial properties to modulate lipid ingestion, improve bioavailability of lipid soluble nutrients and reduce absorption of saturated fats, cholesterol and trans fats.Food emulsions are commonly stabilised by proteins, as they are not only excellent emulsifiers but also provide nutritional benefits to the product. The effects of digestion conditions on interfacial protein structures are complicated because of potential breakdown of these structures by proteolytic enzymes of the gastrointestinal tract. Studies dealing directly with the behaviour of protein-based emulsions under digestion conditions are very limited. This paper provides an overview of the behaviour of oil-in-water emulsions stabilised with globular proteins, namely lactoferrin and β-lactoglobulin. Recent advances in understanding the interactions between interfacial proteins on oil droplets and various physiological materials (e.g. enzymes and bile salts) in in vitro digestion systems are considered. Major emphasis is placed on the recent work carried out in our laboratory at Massey University on the behaviour of milk protein based emulsions (lactoferrin or β-lactoglobulin) during their passage through the gastro-intestinal tract.  相似文献   

12.
The nutritional and medicinal properties of honey have been well-documented. However, honey has occasionally been contaminated with hepatotoxic pyrrolizidine alkaloids as a result of bees foraging on the flowers of pyrrolizidine alkaloid plants. This study establishes a simple and rapid method to determine the marker pyrrolizidine alkaloids in honey using high-performance counter-current chromatography and an off-line electrospray ionization-tandem mass spectrometry, in order to identify the botanical sources responsible for the contamination. The honey sample was initially liquid-liquid extracted (sulfuric acid/hexane, 2:3, v/v) to enrich the pyrrolizidine alkaloids and subsequently purified by a semi-preparative high-performance counter-current chromatography using a solvent system, hexane/butanol/1% aqueous ammonia, 1:1:2, v/v, based on partition coefficient measurements of the target alkaloids. The recovered fractions were profiled by injecting them sequentially into an off-line electrospray ionization-tandem mass spectrometry device to monitor the preparative molecular weight based on elution and extrusion modes. The monitored lycopsamine-type pyrrolizidine alkaloids and their N-oxides (m/z 300, 316; lycopsamine, intermedine, rinderine, and echinatine) were used as the phytochemical markers to identify plants like Chromolaena odorata, Ageratum spp., or Heliotropium spp. to be responsible for the pyrrolizidine alkaloid contamination. Identification of these pyrrolizidine alkaloid plants could guide beekeepers in locating their beehives in order to minimize their potential liver damaging effects.  相似文献   

13.
The white-rot fungus Pleurotus ostreatus produces two types of extracellular peroxidases: manganese-dependent peroxidase (MnP) and versatile peroxidase (VP). The effect of Mn2+ on fungal growth, peroxidase activity profiles, and lignin degradation by P. ostreatus was studied in liquid culture and under solid-state fermentation conditions on perlite, the latter resembling the natural growth conditions of this fungus. The fungus was grown in either a defined asparagine-containing basidiomycete selective medium (BSM) or in a rich peptone medium (PM). Biomass production, as determined by respiration experiments in solid-state fermentation and liquid cultures and fungal growth on Petri dishes, was higher in the PM than in the BSM. Mn2+ affected biomass production only in the PM on Petri dishes. In the nonamended PM, high levels of MnP and VP activity were detected relative to the nonamended BSM. Nevertheless, a higher rate of 14C-lignin mineralization was measured in the Mn2+-amended BSM, as determined during the course of 47 d of fermentation. Mn2+ amendment of the PM increased mineralization rate to that obtained in the Mn2+-amended BSM. The enzyme activity profiles of MnP and VP were studied in the BSM using anion-exchange chromatography. In the nonamended BSM, only minute levels of MnP and VP were detected. On Mn2+ amendment, two MnP isoenzymes (B1 and B2) appeared. Isoenzyme B2 was purified and showed 100% identity with the MnP isoenzyme purified in our previous study from PM-solid-state fermentation (P6). P6 was found to be the dominant isoenzyme in terms of activity level and gene expression compared with the VP isoenzymes. Based on these results, we concluded that Mn2+ plays a key role in lignin degradation under different nutritional and growth conditions, since it is required for the production of MnP in P. ostreatus.  相似文献   

14.
The fatty acid (FA) composition of six macroalgae from the Cystoseira genus, namely Cystoseira compressa, Cystoseira humilis, Cystoseira tamariscifolia, Cystoseira nodicaulis, Cystoseira baccata and Cystoseira barbata, was determined. Polyunsaturated fatty acids (PUFA) corresponded to 29–46% of the total FA detected. C. compressa, C. tamariscifolia and C. nodicaulis stood out for their low PUFA/saturated fatty acid, low n-6 PUFA/n-3 PUFA ratios as well as favourable unsaturation, atherogenicity and thrombogenicity indices, suggesting a high nutritional value with potential applications in the nutraceutical industry.  相似文献   

15.
Yeast single-cell protein and yeast extract, in particular, are two products which have many feed, food, pharmaceutical, and biotechnological applications. However, many of these applications are limited by their market price. Specifically, the yeast extract requirements for culture media are one of the major technical hurdles to be overcome for the development of low-cost fermentation routes for several top value chemicals in a biorefinery framework. A potential biotechnical solution is the production of yeast biomass from the hemicellulosic fraction stream. The growth of three pentose-assimilating yeast cell factories, Debaryomyces hansenii, Kluyveromyces marxianus, and Pichia stipitis was compared using non-detoxified brewery’s spent grains hemicellulosic hydrolyzate supplemented with mineral nutrients. The yeasts exhibited different specific growth rates, biomass productivities, and yields being D. hansenii as the yeast species that presented the best performance, assimilating all sugars and noteworthy consuming most of the hydrolyzate inhibitors. Under optimized conditions, D. hansenii displayed a maximum specific growth rate, biomass yield, and productivity of 0.34 h−1, 0.61 g g−1, and 0.56 g l−1 h−1, respectively. The nutritional profile of D. hansenii was thoroughly evaluated, and it compares favorably to others reported in literature. It contains considerable amounts of some essential amino acids and a high ratio of unsaturated over saturated fatty acids.  相似文献   

16.
In this study, the production and optimization of extracellular lipase from Kluyveromyces marxianus IFO 0288 was investigated by using optimized nutritional and cultural conditions in a yeast medium containing glucose as the carbon source in fully aerobic batch fermentation (150?rpm). The influence of four fermentation parameters (type of lipidic source, initial culture pH, temperature, and length of fermentation) on growth and lipase production was investigated and evaluated using the conventional ??one variable at a time?? approach and response surface methodology. An 18-fold increase in lipase production during 65?h of fermentation was obtained with optimized nutritional (0.5?% olive oil) and cultivation (pH?6.5, 35?°C) conditions by employing the conventional optimization method. By applying the response surface methodology technique the initial pH value of 6.4 and temperature of 32.5?°C were identified as optimal and led to further improvements (up to 18-fold) of extracellular lipase production. The results provide, for the first time, evidence that K. marxianus has the potential to be used as an efficient producer of extracellular lipase with prospective application in a variety of industrial and biotechnological areas.  相似文献   

17.
Continuing with our study characterising Senecio nutans Sch. Bip., we have isolated and identified a simple coumarin, scopoletin, that could be relevant for the biological properties of the species related with the ancestral medical uses. This is the first report of scopoletin from S. nutans. In addition, the extract was analysed for its antioxidant activity using the ABTS and FRAP method as well as providing the first nutritional analyses of this plant from northern Chile highlands.  相似文献   

18.
TheBacillus subtilis alkaline protease(aprA) gene was previously cloned on a pUBHO-derivative plasmid. High levels of expression and gene stability were demonstrated whenB. subtilis cells were grown on the laboratory medium 2XSG.B. subtilis cells harboring the multicopyaprA gene were grown on basal medium, supplemented with 1 % chicken feather as a source of energy, carbon, and nitrogen. Proteolytic and kera-tinolytic activities were monitored throughout the cultivation time. A high level of keratinolytic activity was obtained, and this indicates that alkaline protease is acting as a keratinase. Furthermore, considerable amounts of soluble proteins and free amino acids were obtained as a result of the enzymatic hydrolysis of feather. Biodegradation of feather waste using these cells represents an alternative way to improve the nutritional value of feather, since feather waste is currently utilized on a limited basis as a dietary protein supplement for animal feedstuffs. Moreover, the release of free amino acids from feather and the secreted keratinase enzyme would promote industries based on feather waste.  相似文献   

19.
Perna canaliculus is a nutritional supplement recently studied and highly recommended for its anti-inflammatory effects in both animals and humans. In this study, the physicochemical properties, the microbiological quality, the total lipid content and fatty acids composition of three commercial samples of Perna powder were determined. Subsequently, three simple formulations of extemporaneous oral pastes containing Perna were prepared and designed for veterinary use. Their microbiological stability was assessed after 1-month storage at either room temperature or 35 °C. The results demonstrated that commercial Perna samples lack homogeneity, in regard to some technological properties and fatty acid composition; therefore, a preliminary characterisation of commercial Perna samples is recommended to assure the quality of formulations containing this nutritional supplement. Oral paste formulations are easy and simple to prepare and show good physical and microbiological stability, suggesting their large-scale production.  相似文献   

20.
A systematic study on the metabolome differences between wild Ophiocordyceps sinensis and artificial cultured Cordyceps militaris was conducted using liquid chromatography−mass spectrometry. Principal component analysis and orthogonal projection on latent structure‐discriminant analysis results showed that C. militaris grown on solid rice medium (R‐CM) and C. militaris grown on tussah pupa (T‐CM) evidently separated and individually separated from wild O. sinensis, indicating metabolome difference among wild O. sinensis, R‐CM and T‐CM. The metabolome differences between R‐CM and T‐CM indicated that C. militaris could accommodate to culture medium by differential metabolic regulation. Hierarchical clustering analysis was further performed to cluster the differential metabolites and samples based on their metabolic similarity. The higher content of amino acids (pyroglutamic acid, glutamic acid, histidine, phenylalanine and arginine), unsaturated fatty acid (linolenic acid and linoleic acid), peptides, mannitol, adenosine and succinoadenosine in O. sinensis make it as an excellent choice as a traditional Chinese medicine for invigoration or nutritional supplementation. Similar compositions with O. sinensis and easy cultivation make artificially cultured C. militaris a possible alternative to O. sinensis.  相似文献   

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