Aqueous Protein Extraction Research Articles

Spirulina maxima and its protein extract protect against hydroxyurea-teratogenic insult in mice

Congenital malformations are one of the major causes of child mortality all over the world. In order to prevent them it is necessary to find substances that act as anti-teratogenic agents. In this study hydroxyurea (HU), an antineoplastic and teratogenic drug, was administered to pregnant mice because one of its major mechanisms of teratogenesis is the production of reactive oxygen species (ROS). The aim of this work was to determine if Spirulina maxima (SP) and its aqueous protein extract could protect against HU-teratogenic insult in mouse embryos. SP has been used for a long time because of its nutritional and pharmacological properties. The antioxidant activity, one of the most important, is related to the protein extract due to its content of phycobiliproteins. It was observed that neither SP nor its extract provoked teratogenic effects at any dose tested and even increased vitelline yolk sac circulation. Dams exposed to HU (30 mg/kg, i.p.) presented embryos with multiple alterations in their development. Groups treated with SP or its extract, before and after HU exposure, showed a protector effect in a dose-dependent manner. TBARS test confirmed that the protection effect was related to the antioxidant activity of both SP and its extract.

AQUEOUS EXTRACTION OF OIL AND PROTEIN FROM SOYBEAN AND LUPIN: A COMPARATIVE STUDY

ABSTRACT This study compares the effects of extrusion pretreatment and protease addition during aqueous extraction processing (AEP) of soybean and lupin flakes. AEP of flakes resulted in the lowest yields of oil (56%), protein (71%) and [cream + free oil] (8%) for soybean, while for lupin, yields were 48, 69 and 2%, respectively. AEP protein extraction yields were decreased by extrusion pretreatment, but this pretreatment improved enzymatic action, increasing protein extractability from soybean and lupin by 47 and 26%, respectively. For both protein crops, enzyme-assisted AEP (EAEP) of extruded flakes yielded the highest oil, protein and [cream + free oil] yields, which were 96, 85 21%, respectively, for soybean. Yields for lupin were 81, 77 and 10%, respectively. Extrusion followed by enzyme addition positively impacted demulsification yield, the creams from EAEP of soybean and lupin extruded flakes being the less stable toward enzymatic demulsification. PRACTICAL APPLICATIONS The vegetable oil industry is looking for alternatives to the traditional solvent extraction of oil-bearing seeds, and there is a need to increase the inefficient conventional aqueous extraction of protein from residual defatted meal, a by-product of the oil extraction process. The concept of enzyme-assisted aqueous extraction processing (EAEP) has been successfully developed for extruded soybean material, but its efficiency on other oil-bearing seeds still needs to be demonstrated. By determining the oil and protein extraction yields recovered during EAEP of extruded lupin flakes, the feasibility of transferring this process from soybean to other oilseeds will be established.

Functionality of soy protein produced by enzyme‐assisted extraction

AbstractThis study investigated the potential of enzymes to increase soy protein extractability without causing protein degradation. The aqueous extraction of protein was performed from defatted soy flakes on a laboratory‐and pilot‐plant scale. Yields of protein and reducing sugars were determined in the alkali extracts obtained with cellulases and pectinase, added alone or as cocktails. Using 5% (wt/g of protein) Multifect pectinase resulted in the best improvement of protein yields, which were 50 and 17% greater than the controls in laboratory‐ and pilot‐plant‐scale trials, respectively. This enhanced protein extraction was accompanied by an increased reducing sugar content in the aqueous extract compared with the control. Under the conditions tested, no enzyme cocktail markedly increased the protein yield compared with the use of single enzymes. The solubility curve for Multifect pectinase‐treated soy protein isolate (SPI) was typical of SPI at pH 2–10. Its foam stability significantly improved, but the emulsification properties declined. Multifect pectinase markedly reduced the viscosity of SPI. SDS‐PAGE showed that the α’ and α subunits of β‐conglycinin were modified, and glycoprotein staining showed that these modifications were probably due to a protease secondary activity in the pectinase preparation. One cellulase and one pectinase were identified as effective in modifying the protein and reducing sugar extractablity from the defatted soy flakes.

Electrochemical Nanofabrication Using Crystalline Protein Masks

We have developed a simple and robust method to fabricate nanoarrays of metals and metal oxides over macroscopic substrates using the crystalline surface layer (S-layer) protein of Deinococcus radiodurans as an electrodeposition mask. Substrates are coated by adsorption of the S-layer from a detergent-stabilized aqueous protein extract, producing insulating masks with 2-3 nm diameter solvent-accessible openings to the deposition substrate. The coating process can be controlled to achieve complete or fractional surface coverage. We demonstrate the general applicability of the technique by forming arrays of cuprous oxide (Cu(2)O), Ni, Pt, Pd, and Co exhibiting long-range order with the 18 nm hexagonal periodicity of the protein openings. This protein-based approach to electrochemical nanofabrication should permit the creation of a wide variety of two-dimensional inorganic structures.

Identification and Characterization of the Allergenic Proteins of Bahia Grass (Paspalum notatum) Pollen

Background: Pollen of Bahia grass (Paspalum notatum) represents a major cause of type I allergy in diverse geographical areas, particularly in the southeastern coastal plain area of the United States. The aqueous protein extract of Bahia grass pollen contains the allergenically active components that produce skin-test-positive reactions in sensitive patients. Objective: The emphasis of this study included the identification and characterization of the allergenic proteins present in the crude protein aqueous extract of Bahia grass pollen. Methods: The crude extract of Bahia grass pollen, partially purified by isoelectric focusing and fractionated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), was electroblotted onto nitrocellulose membranes, probed with sera from patients skin test positive to Bahia grass and detected using anti-human IgE conjugated peroxidase. Results: Four allergenic proteins of Bahia grass pollen with estimated molecular weights of 45, 33, 31 and 28 kD were identified and characterized. Following treatments with deglycosylation enzymes, the 4 allergens retained their antigenic reactivity with Bahia-grass-allergic patient sera containing polyclonal IgE antibodies. Conclusion: The crude extract of Bahia grass pollen contains many proteins but only 4 have allergenic reactivity. Following deglycosylation treatment, Bahia grass allergenic proteins have retained their antigenic reactivity with Bahia-grass-allergic patient sera containing polyclonal IgE antibodies. Four proteins reactive with IgE were detected, but the 33-kD protein (pI of 6.59) was the most reactive.

Diet and Antioxidant Status

Arthrospira is a cyanobacteria broadly cultivated worldwide due to its high nutritional value, metabolites with therapeutic properties, non-toxic character and easy culture. The genus Arthrospira has been historically confused with the genus Spirulina (with potential toxicity) therefore, an accurate taxonomic identification of strains for food applications, is essential. In this study we compared two strains of Arthrospira with remarkable morphological differences, preliminary classified as Arthrospira maxima (CCM-UdeC 040) and Arthrospira platensis (CCM-UdeC 136). Despite of their morphological differences, we confirmed that both strains belong to the same genetic species, according to their ribosomal ITS (internal transcribed spacer) sequences. We also compared the biochemical composition of both strains, including analysis of antioxidant properties of their aqueous protein extracts, both crude, as well as, hydrolyzed with commercial proteases. Biotechnological potential of these strains as raw material for nutraceutical and functional food markets is discussed. Strain CCM-UdeC 040 showed the highest biotechnological potential so further studies should be conducted for optimizing its culture conditions.

A new survey of Brazilian marine algae for agglutinins

Aqueous protein extracts from 30 Brazilian marine algae were examined for haemagglutinating activity using native and enzyme-treated rabbit, chicken, sheep and human erythrocytes. Most extracts agglutinated at least one of the blood cells used. Sheep and rabbit erythrocytes were more suitable for detection of the agglutinating activity. The minimum protein concentration necessary to produce positive agglutination was usually lower with enzyme-treated erythrocytes than native ones. The five algal protein extracts showing the greatest haemagglutination titre were tested for sugar-binding specificity. Only the activity present in the green alga Cauler pacupressoides was inhibited by simple sugars and not by the glycoproteins tested. The activity of the other four extracts was inhibited by at least one of the glycoproteins utilised.

Enzyme linked immunosorbent assay for detecting antibody to Trichomonas vaginalis: use of whole cells and aqueous extract as antigen.

An enzyme linked immunosorbent assay (ELISA) for detecting antibody to antigenic Trichomonas vaginalis macromolecules has been identified using whole cells or an aqueous protein extract as antigen. The test was developed under optimum conditions using serum samples from experimental animals. The sensitivity of the ELISA was equal to or greater than that obtained by radioimmunoprecipitation and electrophoresis-fluorography techniques. The ELISA was capable of assessing antibody responses during the development of lesions in animals inoculated subcutaneously and it reproducibly measured the individual classes immunoglobulins directed at T vaginalis. The colorimetric assay was also suitable for showing cross reactivity between trichomonal species as well as between different strains of T vaginalis. Conditions established for monitoring antibody to trichomanads in immunised rabbits or infected mice were equally effective for human materials, such as serum or vaginal washes. Serum from experimental animals or infected people showed high concentrations of IgG, IgA, and IgM antibody to trichomonads. Only antibodies of the IgG and IgA class were detected in vaginal washes from women with acute trichomoniasis. No IgE antibody to trichomonads was found under a variety of conditions in serum samples from patients or experimental animals.

A Process to Produce Light Colored Protein Isolate from Defatted Glandless Cottonseed Flour

ABSTRACTLight colored protein isolates could be produced from aqueous protein extract (at pH 9.0) of defatted cottonseed flour by filtering through an ultrafiltration membrane with 100,000 MWCO (molecular weight cut off) pore size and then spray‐drying the retentate. The yield of this protein fraction was approximately 68% of the extracted solid. About 15% of the extracted solid was recovered with the low molecular fraction (50,000 daltons) when the permeate of 100,000 MWCO was applied to 50,000 MWCO membrane. Most of the color‐causing pigments were associated with the low molecular fraction.

Effects of Preparative Processes on the Composition and Functional Properties of Protein Preparations from Candida utilis

ABSTRACTProtein preparations were made from continuously grown Candida utilis cells using processes which included cell disruption, aqueous protein extraction, nucleic acid reduction, protein precipitation and freeze‐ or spray‐drying. The composition of the preparations was in the range 48–57% crude protein and 2–11% RNA, depending on the procedures used for concentrating protein and reducing nucleic acid. Functional properties examined included water‐binding capacity, emulsifying properties, nitrogen and protein solubility, fat absorption, foaming properties, and bulk density. No single yeast preparation was superior to the others in all properties tested. Although heating processes, and in particular heat shocking of cells at 68°C with subsequent incubation at 50–55°C, were generally detrimental to functional properties, no processing procedure always affected all functional properties in the same way. The functional properties of some of the yeast preparations were found to compare favorably with those of the standard reference proteins, soy protein isolate, and sodium caseinate.

Non‐effect of dilute alkali solutions on the number average granule diameters of some legume starches

SummaryStarches of field bean, garbanzo and lentil were isolated according to a detailed separational scheme (Anderson & Romo, 1976) which employed several different aqueous protein extraction media adjusted to pH values in the range of 5.5 to 9.5. Number average granule diameters were determined for the isolated starch granules using photomicroscopy in order to ascertain the effect of protein extraction medium alkali concentration, if any, on this parameter. It was established that the number average granule diameters of the three starches under investigation were not influenced by a change in alkali concentration of the protein extraction‐medium within the pH range studied. Accordingly, garbanzo starch granules exhibited a pooled number average granule diameter of 24 μm with a standard deviation of 4 μm, while both lentil and field bean starch granules exhibited pooled number average diameters of 27 μm with a standard deviation of 7 μm. Granule size distributions based on more than 1100 separate measurements were also constructed for the three starches prepared at neutral pH in the form of histograms for the sake of comparison. The distributions for field bean and lentil are similar, both showing some skewness with that for field bean being most pronounced. The distribution for garbanzo, on the other hand, is more normal and much more narrow than the other two examples.

The aqueous extraction of protein from plant tissue with the use of electrodialysis

An electrodialysis system was used for the aqueous extraction of protein from frozen tissue of mung bean (Phaseolus aureus Roxb.) hypocotyl followed by gel electrophoresis and assay of polyphenol oxidase, esterase, and fungal glucose oxidase isozymes. The isozymes tested showed a consistent increase in activity with the increase in current, between 0 and 100 mA, suggesting that current application can overcome, in part, alterations in protein fraction during the aqueous extraction of plant tissue. Details of the extraction procedure and the construction of the electrodialysis system are described.