Chemical and functional characterization of major protein fractions extracted from nontoxic Jatropha curcas byproduct meals

Jatropha curcas seeds are a suitable source of oil for biofuel, among other use. A protein-rich meal is obtained after oilseed extraction. The goals of this study were to determine the physicochemical and functional properties of a nontoxic genotype of J. curcas defatted meal (JCDM) and the seed storage protein fractions to identify future applications. Both glutelin and globulin were the predominant protein fractions obtained from JCDM (42.03 and 20.17 g/100 g of protein, respectively). Leucine, phenylalanine + tyrosine, and histidine content of JCDM and protein fractions met the Food and Agriculture Organization/World Health Organization recommendation for children. The protein solubility (PS) profiles showed minimum values (5.3%–59.7%) at pH 5–6 and maximum at pH 2 (79.7%–81.6%) and above pH 10 (84.6%–89.8%). These findings suggest that JCDM proteins could be used in the formulation of juice or protein-based beverages. All the proteins showed the highest values for foam expansion (231%–285%) at pH 9. JCDM and the albumin fraction formed highly stable foams at pH 9, while the globulin and glutelin foams were stable at pH 3 and 2, respectively. Protein with stable foams, like those from jatropha are suitable for application in ice cream, mousse, among others. The emulsion activity index had similar behavior as foam expansion, but did not follow a specific trend. Thus, the proteins are suitable for use in salad dressing, sausages, comminuted meats, and mayonnaise. Taken together, JCDM protein and its soluble protein fractions have strong promise as alternative proteins for food structuring.     

<Emphasis Type="Italic">Lesquerella fendleri</Emphasis> protein fractionation and characterization

Lesquerella fendleri is a promising new crop whose seed contains hydroxy FATG with potential industrial uses as well as substantial amounts of valuable gums. The defatted L. fendleri seeds also contain more than 30% protein. The objective of this study is to process and characterize this protein component for possible future uses in food. Hexane-defatted seed has more than 30% protein content. Defatted lesquerella meal was extracted sequentially with 0.5 M sodium chloride (2×), water, 70% ethanol, and 0.1 N sodium hydroxide (2×). Each sodium chloride extract was dialyzed against deionized water and centrifuged to separate the water-soluble fraction (albumin) from the salt-soluble fraction (globulin) before freeze-drying. The ethanol extract and the neutralized sodium hydroxide extracts (glutelin) were dialyzed against water and freeze-dried. Albumin had the highest proportion of lysine and sulfur amino acids per 16 g nitrogen among all the fractions analyzed. Glutelin and globulin accounted for the highest amount of protein nitrogen. SDS-PAGE of the reduced albumin, globulin, and glutelin showed the presence of several protein bands with M.W. ranging from 7 to 98 kDa. Nitrogen solubility of defatted lesquerella meal from pH 2 to 12 indicated a solubility minimum of 15% around pH 4.2 and a solubility of 75% at pH 11.5. Nonprotein nitrogen of defatted meal was 12% of total nitrogen. Defatted lesquerella meal has the potential for food use based on good nitrogen solubility and good amino acid composition.     

Protein fractionation and properties of salicornia meal

Salicornia bigelovii Torr. is an annual salt-marsh oilseed plant. Hexane-defatted salicornia meal was extracted sequentially with 0.5 M sodium chloride (2x), water, 70% ethanol, and 0.1 N sodium hydroxide (2x). Each sodium chloride extract was dialyzed against deionized water and centrifuged to separate a water-soluble fraction (albumin) from a salt-soluble fraction (globulin) before freeze-drying. Ethanol extracts and neutralized sodium hydroxide extracts (glutelin) were dialyzed against water and freeze-dried. Globulin accounted for the highest amount of protein nitrogen, followed by glutelin and albumin. SDS-PAGE of reduced albumin, globulin, and glutelin showed a number of protein bands. Nitrogen solubility of defatted salicornia meal from pH 2 to 11 indicated a minimum solubility of 22%, around pH 4.5. Nonprotein nitrogen of defatted meal was 23% of total nitrogen, higher than defatted soybean, sunflower, and rapeseed meals. Albumin had the highest proportion of lysine and sulfur amino acids per 16 g nitrogen among all the fractions analyzed.     

Heat-induced gelation of rapeseed proteins: Effect of protein interaction and acetylation

The gel-forming abilities of a rapeseed protein isolate, composed of 70% globulin (cruciferin) and 30% albumin (napin), and their individual protein components, were investigated. The influence of acetylation upon the gelation properties was also studied. Highest gel strength (measured as shear modulus) of the isolate was obtained at pH values around 9, which is between the isoelectric points of both major proteins. Purified cruciferin gave the highest shear modulus values, with maxima at pH 6 and 8. Weak and poorly stable gels exhibiting strong hysteresis were obtained with isolated napin. Acetylation resulted in a pH shift of the shear modulus maximum of the protein isolate to about 6. The gelation temperature of the acetylated isolate had the highest pH and concentration dependence compared with the other proteins.     

Properties of Soy Protein Produced by Countercurrent,Two-Stage,Enzyme-Assisted Aqueous Extraction

Enzyme-assisted aqueous extraction processing (EAEP) is an environmentally friendly technology where oil and protein can be simultaneously extracted from soybeans by using water and protease. Countercurrent, two-stage, EAEP was performed at a 1:6 solids-to-liquid ratio, 50 °C, pH 9.0, and 120 rpm for 1 h to extract oil and protein from soybeans. The skim fractions were produced by three methods: (1) by treating with 0.5 % protease (wt/g extruded flakes) in both extraction stages; (2) by treating with 0.5 % protease in the 2nd extraction stage only; and (3) by using the same two-stage extraction procedure without enzymes in either extraction stages. Countercurrent, two-stage, protein extraction of air-desolventized, hexane-defatted, soybean flakes was used as a control. Solubility profiles of the skim proteins were the typical U-shaped curves with the lowest solubility at the isoelectric point of soy protein (pH 4.5). The use of the enzyme slightly improved solubility of the recovered protein with hydrolyzed proteins having higher solubilities at acid pH. Emulsification and foaming properties were generally reduced by the use of enzyme during EAEP extractions. The skims produced with protease-extracted (hydrolyzed) proteins gave gels with lower hardness than did unhydrolyzed proteins when heated at 80 °C. The essential amino acid compositions and protein digestibilities were not adversely affected by either extrusion or extraction treatments.     

Electrophoretic study of albumins and globulins of 4 genotypes of Canavalia ensiformis

Polyacrylamide gel electrophoresis (PAGE) and PAGE-SDS were used to study seed albumins and globulins of Canavalia ensiformis. In PAGE the concentration of acrylamide used in the upper gel was 4.0% with a pH of 6.7 and in the lower gel 7.5% and 10% of acrylamide were used with a pH of 8.9. In PAGE-SDS the concentration of acrylamide was 4.4% with a pH of 6.8 in the upper gel and 7.5% and 12.6% with a pH of 8.8 in the lower gel. The material used were the Venezuelan genotypes Tovar, Yaracuy, Original and U-02. The albumins and globulins were extracted with a 0.5 M NaCl solution and then separated by dialysis against water and lyophilized. These protein fractions represented 84.85% of the total amount of protein in seeds. The albumins were separated in PAGE with 7.5% acrylamide into five fractions and globulins into six, with similar electrophoretic patterns between genotypes. In a similar manner, the patterns obtained in PAGE with 10% acrylamide were the same for all genotypes, showing five bands for albumins and three bands for globulins. With PAGE-SDS containing 7.5% of acrylamide, albumins were separated into as many as eight components, and globulins into as many as seven bands with mobilities between 0.2981 and 0.9932, with different patterns for each genotype. Also the patterns PAGE-SDS at 12.6% of acrylamide were different for the genotypes, separating proteins into a greater number of bands. The albumins showed as many as twenty-one bands with mobilities between 0.2603 and 0.7398, and globulins as many as sixteen bands with mobilities between 0.2454 and 0.7390. The PAGE patterns of the genotypes analyzed did not show differences between them. However, with PAGE-SDS different electrophoretic patterns were obtained which varied in the number and intensity of the bands, making it possible to distinguish the genotypes studied. The molecular weight of the albumins varied between 76,000 and 12,000 daltons and of the globulins between 80,000 and 12,000 daltons.     

Yield and functional properties of air-classified protein and starch fractions from eight legume flours

Eight legumes were pin-milled and air-classified into protein (fine) and starch (coarse) fractions and their functional properties compared with those of soybean and lupine flours. The fine material which represented 22.5 to 29% of the original flours contained from 29 to 66% protein as well as a high proportion of the flour lipids and ash. The coarse material contained 51 to 68% starch and much of the crude fiber which was dense and concentrated in the starch fraction. Generally legumes which showed highly efficient starch fractionation gave lower recoveries of protein in the fine material. High values for oil absorption, oil emulsification, whippability and foam stability were characteristics of the protein fractions, while starch fractions gave high water absorptions, peak and cold viscosities. Gelation occurred in both air-classified fractions. Pea and northern bean, chickpea and lima bean flours, and airclassified fractions gave generally higher values in the functional property tests, while fababean, field pea, mung bean and lentil gave high protein fractionation in the air classification process.     

An Investigation of pH Mediated Extraction and Precipitation of Phosphorus from Sludge Using Microfiltration: Processing and Costs

Membrane filtration of wastewater sludge is a feasible technology for the recovery of sustainable nutrients in bacteria and particle-free solutions. Diafiltration and acidification strategies were investigated for the recovery of phosphorus (P) from trout farm sludge. Extraction costs were determined using a pilot-scale unit. pH of 2.7 was found to maximize the extraction of P (and metals) and highest concentrations were achieved by acidic leaching of the sludge sediment. Levels of P, Ca, Fe, Mg, and K recovered in soluble fractions were 418 mg/L, 6730 mg/L, 66.8 mg/L, 29 mg/L, and 34.1 mg/L, respectively. Operational costs associated with acidification and power consumption were estimated to be 0.018 kWh/L permeate or 0.037 kWh/g P obtained. The extraction of P by membrane filtration was mainly dependent on pH and cost was considerably lower than that for P-based fertilizers. Owing to the high concentration of Ca and P in the permeate fractions, 99% of the soluble P was precipitated from solution at pH 8. Elemental analysis and FTIR of the precipitate obtained indicated to be carbonated calcium-deficient hydroxyapatite.     

Plastics from an Improved Canola Protein Isolate: Preparation and Properties

Canola meal proteins were solubilized from canola flour at pH 12 using sodium hydroxide solution. Proteins were then precipitated sequentially at pH values ranging from 11 to 3 in decrements of 1 pH unit. The weight distribution and the properties of these fractions were analyzed. The majority (>76%) of the recovered proteins were precipitated at pH values at or below 7. Another substantial fraction was precipitated at pH 11. The functional and thermal property (differential scanning calorimetry) analyses showed that this protein fraction exhibits the highest water holding capacity and lowest melting point. The plastics prepared with refined protein isolates (with pH 11 fraction removed) showed higher water resistance, tensile, and flexural strength, toughness, and elongation values compared to those prepared with standard canola protein isolates. This shows that mechanical and water resistance properties of protein-based plastics can be enhanced using improved protein isolates.     

Electrophoretic fractionation of soluble antigenic proteins from the seed ofRicinus communis (castor bean)

A water-soluble, heat-stable protein component of castor seed meal was subjected to paper-strip electrophoresis in buffers of different chemical composition, pH values, and ionic strengths. It was shown that phosphate buffer at pH 7.4 to 8.0 and an ionic strength of approximately 0.05 gave a sharp resolution of castor seed proteins into bands which would bind bromophenol blue. Spies' Allergen CB-1A was shown to be resolved into six or more components at pH 8.0. Each major component band was found to be antigenic by passive cutaneous anaphylaxis in guinea pigs that were sensitized with rabbit antiserum to the crude castor seed protein preparation. Five bands were shown to be allergenic to humans. The results appear to support earlier observations (1,2,10) that castor bean seed allergenicity to humans may be caused by more than one antigen in Spies' Allergen CB-1A and possibly by other antigens present in the seed but either absent from, or greatly reduced in concentration in, allergen CB-1A. The water-soluble component of Altschul's active castor seed lipase was resolved into eight component bands, two of which did not appear in the electrophotograms of the heat-processed preparation CB-1A S.R.I. A laboratory of the Western Utilization Research and Development Division, Agricultural Research Service, U.S. Department of Agriculture.     

Polyphenolic extracts of Pinus radiata bark and networking mechanisms of additive‐accelerated polycondensates

The use of various chemicals for extracting polyphenolic fractions (tannins) from Pinus radiata bark was examined with the aim of obtaining high yields of high‐quality tannins to be used as wood adhesives. Extractions carried out under very highly alkaline conditions (pH > 10.5) gave relatively high yields but also excessive viscosity values even in 30% (w/w) solutions, and this demonstrated their inability to function as wood adhesives. Solutions (30% w/w) of mildly extracted (pH < 8.3) fractions gave workable viscosity values and were used in a subsequent study. A rapid acceleration effect was observed in these fractions when ammonia was used as a catalyst. Solid‐state, cross‐polarization/magic‐angle‐spinning ¹³C‐NMR of the cured samples showed evidence proving the existence of benzyl amine bridging networks in their hardened state. Simultaneously accelerated copolymerization could be observed in phenol–resorcinol–formaldehyde/P. radiata bark tannin mixtures with the addition of ammonia, as indicated by viscosity measurements. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2487–2493, 2007     

Enzyme-Assisted Aqueous Extraction of Oil and Protein from Soybeans and Cream De-emulsification

The effects of two commercial endoproteases (Protex 6L and Protex 7L, Genencor Division of Danisco, Rochester, NY, USA) on the oil and protein extraction yields from extruded soybean flakes during enzyme-assisted aqueous extraction processing (EAEP) were evaluated. Oil and protein were distributed in three fractions generated by the EAEP: cream + free oil, skim and insolubles. Protex 6L was more effective for extracting free oil, protein and total solids than Protex 7L. Oil and protein extraction yields of 96 and 85%, respectively, were obtained using 0.5% Protex 6L. Enzymatic and pH treatments were evaluated to de-emulsify the oil-rich cream. Cream de-emulsification generated three fractions: free oil, an intermediate residual cream layer and an oil-lean second skim. Total cream de-emulsification was obtained when using 2.5% Protex 6L and pH 4.5. The extrusion treatment was particularly important for reducing trypsin inhibitor activity (TIA) in the protein-rich skim fraction. TIA reductions of 69 and 45% were obtained for EAEP skim (the predominant protein fraction) from extruded flakes and ground flakes, respectively. Protex 6L gave higher degrees of protein hydrolysis (most of the polypeptides being between 1,000 and 10,000 Da) than Protex 7L. Raffinose was not detected in the skim, while stachyose was eliminated by α-galactosidase treatment.     

Amino acid composition of some Amaranthus sp. grain proteins and of its fractions

This study was carried out to determine the protein content of several Amaranthus sp. grains. Findings revealed this has a high lysine (5.3 to 6.3 of the protein) and sulphur amino acids content (3.4-4.0%), while leucine could well be limiting when those seeds are used as a sole protein source in food. Using the correction for in vitro protein digestibility, the chemical score varied from 50 to 67. The calculated protein efficiency ratios and biological values ranged from 1.39 to 1.80 and 53 to 68, respectively. Considering that amaranth grain is a good supplement to cereal grain, the protein of A. hypochondriacus HH5 (yellow seeds) and A. anclancalius (black seeds) was fractionated into albumin, globulin, prolamin and glutelin. The average proportions between those soluble proteins were 65:17:11:7, respectively. Albumin had the highest lysine content (7.3-8.2%), and globulin the highest methionine (4.1-5.3%) and phenylalanine (6.0-6.1%) content. Prolamin had the highest threonine (4.6-5.4%) and leucine (6.8-6.9%) content, while glutelin had a very low methionine content (0.6-1.0%). Based on the above-mentioned findings, the authors conclude the variation in the amino acid composition of the protein fractions can be used for genetic protein improvement.     

Effect of pH on Separation Performances in High-Performance Liquid Chromatography of Antibacterial Peptides from the Spleen of Japanese eel,Anguilla japonica

The present study was made to determine the optimum pH for isolating antibacterial peptides from the spleen of Japanese eel, Anguilla japonica, by high-performance liquid chromatography (HPLC). The recovery rates of the peptides were investigated by using buffers with three pH values (pH 3, pH 4, and pH 5) in ion-exchange chromatography (IEC) of the spleen protein sample with the molecular weight (MW) < 10 kDa. Following this, for the fractions obtained from IEC, we continued to study the effect of four pH values (pH 2, pH 7, pH 9, and pH 12) on the separation efficiency in reverse-phase high-performance liquid chromatography (RP-HPLC). The results showed using the buffer with pH 4 in IEC could achieve the highest rate of recovery, which was 5.4 fold to that of pH 3 and 1.36 fold to that of pH 5. The treatment at high pH value (pH 9) did significantly affect the chromatographic separation behaviors, which produced more than twice the peak numbers than those in other three pH values. The optimized pH would be helpful for isolating antibacterial peptides from the spleen of eel.     

Elimination of toxic compounds, biological evaluation and partial characterization of the protein from jojoba meal (Simmondsia chinensis [Link] Schneider

The purpose of this study was to establish a new methodology to remove the toxic compounds present in jojoba meal and flour. Also, to perform the biological evaluation of the detoxified products and to chemically characterize the protein fractions. Jojoba meal and seed without testa were deffated with hexane and detoxified with a 7:3 isopropanol-water mixture which removed 86% of total phenolic compounds and 100% of simmondsins originally present, the resulting products had reduced bitterness and caused no deaths on experimental animals. NPR values obtained for diets containing such products were significantly different from those obtained with the casein control (p less than 0.05). Total protein was made up of three different fractions: the water-soluble fraction was the most abundant (61.8%), followed by the salt-soluble (23.6%), and the alkaline soluble fraction (14.6%). The nitrogen solubility curves showed that the isoelectric point for the water-soluble and salt-soluble fractions was pH 3.0, while that of the alkaline fraction fell in the range of 4.5-5.0. All fractions had a maximum solubility at pH 7.0. The methodology reported here, offers a viable solution to eliminate toxic compounds from jojoba meal or seeds, and upgrades the potential use of products such as animal feed or raw material for the production of protein isolates.     

乙醇/硫酸铵双水相体系萃取甘草酸钾的研究

实验考察了乙醇/硫酸铵双水相萃取甘草酸钾的可能性及其影响因素,结果表明,甘草酸钾在该体系的分配系数K和收率均随乙醇、硫酸铵质量分数的增加而增大,而随着pH的增加先增加后减小。且在w(乙醇)=35 1%,w(硫酸铵)=17 7%,pH=6 0左右时,分配系数K可达13 7,收率η可达96 3%。这将为甘草酸钾的提取分离提供一种新的可能。     

Pulmonary surfactant: Distribution of lipids,proteins and surface activity in ultracentrifugation of rabbit pulmonary washing and derived fractions

Lavage from normal adult rabbit lung and two known derived fractions, Fraction T and Fraction S, were subjected to either differential ultracentrifugation in 1.090 g/ml KBr or sucrose density gradient ultracentrifugation; the surface activity of the lipid extract of selected fractions was measured. In differential ultracentrifugation, the three starting materials yielded a pellicle containing > 85% of the phospholipid with <1% protein. In sucrose density gradient ultracentrifugation: pulmonary washing, containing about equal weights of phospholipid and protein (60% albumin, 20% sIgA, 10% IgG, 10% minor proteins), produced one single band at density 1.040, containing virtually one single protein, namely >80% of the total sIgA (protein T) and up to 60% of the total phospholipid, whereas all the albumin and IgG were found at very low densities, 1.010 and 1.025, respectively; Fraction T, having nearly equal weights of one signle protein, sIgA, and phospholipid, produced two contiguous bands at densities 1.059 and 1.078, totalling >85% of its phospholipid and <25% of its protein, the balance of which was found free of phospholipid at densities 1.020 to 1.050; comprising >80% of the phospholipid and <20% of the protein of pulmonary washing, Fraction S yielded two small bands at densities 1.028 and 1.044 and a major band at d=1.059. In surface activity measurements: when the total lipid extract of the bands from the sucrose density gradient ultracentrifugation was spread as a film, in spite of similarly high dipalmitoyl lecithin contents (about 70% palmitoyl lecithin contents (about 70% palmitoyl residue), the lipid of the band of Fraction T and that of the high density band of Fraction S were very active (γ _min=0); whereas the lipid of the band of pulmonary washing and that of the lowest density band of Fraction S were not active,γ _min being 18 dyne/cm and 21 dyne/cm, respectively. This wokk brings forth three major conclusions. First, under conditions which are used to isolate serum lipoproteins, no lipoprotein was obtained from either of the three surfactant fractions and most of the lipid was found virtually free of protein. Second, the isopicnic equilibrium of a given ultracentrifugation fraction varied with the molecular structure of its constituents and could not be accounted for by the latter’s average densities; instead, major roles must be player by particle geometry and their water contents. Third, although the various lipid samples contained the same quantities of palmitoyl residues (70%), the surface activities varied with the physical state of the lipid, method of assay, and some other undefined factors.     

Protein fraction distribution in milling and screened physical fractions of grain amaranth

The purpose of the study was to establish the protein distribution based on solubility in physical fractions of amaranth flour, in particular between the flour from the germ and that from the perisperm. The protein distribution was obtained applying a series of solvents sequentially utilized in the classical methodology of Osborne & Mendel. The sample of A. cruentus weighing 2000 g was divided into 4 subsamples of 500 g each. One was left as the control while the other 3 were ground individually with a mill. Each flour was screened through 18, 20, 30 and 40 mesh screens, so that 5 fractions were obtained from each of the whole grain flours. Samples of each screened fractions were observed by stereoscopy and analyzed for moisture, fat and protein. This characterization suggested that the fraction above the 30 mesh screen and the flour which passed the 40 mesh screen probably were the perisperm and germ respectively. The 30 mesh sample contained 2.34 fat and 9.05% protein while the 40 mesh contained 16.18% fat and 26.46% protein. The extraction and partitioning of the proteins indicated that the most important fractions in germ and perisperm were the water soluble and glutelins measured by Kjeldahl. The relationship of the water soluble + globulin to glutelins ratio was 2.1 to 1 in the whole grain, 1.9 to 1 in the perisperm and 1.7 to 1 in the germ. The distribution of proteins was very much alike between germ and perisperm. The levels of prolamines were quite low. The protein extraction of the perisperm proteins retained on the 30 mesh screen was low (71.1%) measured by Kjeldahl and 47.4% with the Bradford method to measure protein.     

Fractionation and Some Chemical Studies on Ailanthus excelsa Roxb. Seed Protein

The unavailability of protein foods, particularly in the context of population growth, has been an important factor in the protein malnutrition encountered in developing countries. The fractionation, gel filtration and polyacrylamide gel electrophoresis (PAGE) of Ailanthus excelsa seed (a nontraditional source containing 15.81% protein) proteins were carried out in the present study, and their solubility profiles, surface topographies and amino acid compositions were evaluated. The globulin fraction dominated the seed protein composition, accounting for 51.31% (w/w) of the total soluble proteins in the seeds. Protein isolate and protein fractions of A. excelsa seeds showed similar topographical structures to those of other plant seed proteins. Analysis of the isolated proteins identified 17 amino acids, of which nine were essential. Gel filtration on Sephadex G-200 revealed the presence of seven components. PAGE detected different polypeptide bands in the range of 28.8−154.9 kDa in the protein isolate as well as in protein fractions for A. excelsa. The amino acid compositions, the solubility patterns and the high abundances of low molecular weight proteins indicate that the isolated seed protein of A. excelsa may be a potential food protein.     

细菌纤维素的静态发酵及物理性质研究

以木醋杆菌为生产菌,在静态培养条件下,通过改变碳源及初始pH值等条件,初步研究了发酵过程中pH值、残糖以及纤维素产量的变化,并初步测定了纤维素的性质。结果发现在葡萄糖、麦芽糖、蔗糖、甘露醇四种碳源中,甘露醇获得的纤维素产量最高;菌体在初始pH值4～6范围内生长较好,pH值为4.5时产量最高;扫描电镜观察菌体长度大约为2μm,宽度为0.8μm左右,纤维直径分布在10～80nm之间,其中80%主要分布在20～50nm,在30～40nm之间最多;红外光谱显示了细菌纤维素葡聚糖的特征吸收;热重分析表明,细菌纤维素最大失重速率温度为342.9℃,在622.2℃,失重率达到72.26%;每克湿纤维素膜含水130～210g,含水率超过99%,而每克干纤维素膜能吸水3.1～5.0g。