Isolation,fractionation and characterisation of proteins from Mucuna bean

The chemical composition and fractional distribution of protein isolates prepared from species of Mucuna bean were studied. Using six different extraction media, the yield of protein based on the Kjeldahl procedure varied from 8% to 34%, and the protein content varied from 75% to 95%. When the yields were high, the colour of the isolates generally tended to be dark and unsatisfactory. Hence, the use of chemical treatments and high pressure processing were explored.     

蛹虫草免疫调节蛋白分离纯化、结构表征与免疫调节活性研究

目的 探究蛹虫草蛋白质的免疫调节活性和一级结构。方法 过碱溶酸沉法提取蛹虫草蛋白质,并且用阴离子交换层析法和葡聚糖凝胶层析法对其进行分离纯化,获得一种免疫调节效果较好的组分(记为CMP 2b),通过建立小鼠巨噬细胞免疫调节模型对其组分进行活性评价得到活性最佳的组分,通过基质辅助激光解吸飞行时间质谱测得其分子量大小,通过蛋白质谱解析出其蛋白质一级结构。通过小鼠巨噬细胞研究其对巨噬细胞RAW264.7增殖活性、吞噬率、一氧化氮(nitrogen monoxide, NO)分泌量、免疫因子白细胞介素-1β (interleukin-1β, IL-1β)、免疫因子白细胞介素-6 (interleukin-6, IL-6)、干扰素-γ (Interferon-γ,IFN-γ)和肿瘤坏死因子-α (tumor necrosis factor-α, TNF-α)释放量等方面。结果 通过阴离子交换色谱和葡聚糖凝胶色谱分离纯化出一种蛹虫草免疫调节蛋白CMP 2b,由蛋白质谱测得它由196个氨基酸组成,分子量为22.460 kDa;通过建立巨噬细胞免疫调节模型,研究得出CMP 2b对巨噬细胞的增殖能力、吞噬能能力有显著提高,细胞增殖率最高达到了空白对照组的152.91±5.55%,吞噬能力提高了23.34%;并且促进巨噬细胞分泌NO、ROS、IL-1β、IL-6、IFN-γ及TNF-α,其中NO分泌水平分别达到了空白对照组的2.31倍,ROS 分泌水平达到阳性对照组 LPS的 82.33%,TNF-α、IL-1β、IFN-γ和IL-6分泌量分别为空白对照组的5.51倍、17.42 倍、4.18倍和26.75 倍,显著增强了巨噬细胞免疫调节能力。     

Isolation and composition of proteins from leaves of plants grown in Ceylon

Proteins were isolated from fresh leaves of twelve plant species grown in Ceylon. Contents of total N, non-protein N and protein N in the original leaves, and protein N in the isolated protein were determined and the percentage extractability of N was calculated. Analyses of the protein isolates for total N, ash, Ca, Fe and all the amino acids are reported. The protein isolates were rich in all but one of the amino acids namely methionine. However, the lysine contents were greater than in some standard proteins. The protein scores were comparable to the standard proteins. The percentage extractability ranged from 9.3 to 91 %. A high proportion of the nitrogen Was found as non-protein. It was concluded that the proteins from the leaves examined could provide a dietary supplement.     

Texturisation and modification of vegetable proteins for food applications using microbial transglutaminase

Microbial transglutaminase (MTG) isolated from Streptomyces mobaraensis has been available on a commercial scale for several years. MTG generates inter- and intramolecular cross-links between γ-carboxylamide groups of glutamine residues and ɛ-amino groups of lysine residues in proteins. Due to its great potential to improve various functional properties of proteins, MTG is mainly used to enhance texture, stability, and water binding. Application of MTG for the production of plant protein-based foodstuffs such as tofu, noodles, bread and bakery products, is still limited to raw materials from soybean and wheat. However, with the increasing demand for vegetarian foods, the utilisation of novel proteins as functional ingredients, e.g. from peas, lupins, sesame, and sunflower, seems promising. To open new horizons for MTG application, this review aims at demonstrating the actual potential of MTG in processing foodstuffs based on vegetable proteins. Particular focus was laid on novel plant protein sources suitable for cross-linking with MTG. Furthermore, strategies for improving texture and nutritive value of the proteins are discussed.     

Production of Vegetable Protein from Rapeseed Press-Cake Using Response Surface Methodology,Weighted Multivariate Index,and Desirability Function: A Way to Handle Correlated Multiple Responses

The majority of present day industrial processes/products are defined by several quality characteristics, for which the process variables need to be precisely modulated to meet the required specifications. Hence, the multi-response process optimization has become an increasingly important and demanding task. In practice, many of these quality characteristics under consideration show conflicts among themselves, which need to be simultaneously satisfied. This situation is aggravated when the quality characteristics show correlation. To remedy this shortfall, we present a novel multi-objective process optimization approach, based on weighted principal components (principal component scores weighted by their respective eigen values), response surface methodology and desirability function. The implementation of the suggested approach is presented on a study that discusses the optimization of light-colored and reduced phytate containing protein extraction process from rapeseed press-cake. The effectiveness of the said approach was confirmed by performing additional confirmatory experiments at the predicted optimal condition. Furthermore, this study suggests the feasibility of the exploitation of the waste oilseed cake for extraction of high quality vegetable protein, using viable process and simple computational procedure. This study also briefly highlights performance analyses in cross-flow batch extraction scheme using optimized condition.     

Preparation and application of vegetable proteins, especially proteins from sunflower seed, for human consumption. An approach

About 80% of the world protein production are of vegetable origin. More than half the vegetable protein is fed to animals, whereas merely 10 kg protein per capita are obtained from meat, milk and eggs per year. Therefore, and because of rising prices for raw materials and energy the production and the firsthand utilisation of proteinacous plants for foodstuffs are a worldwide problem. As future source of protein for human nutrition sunflower seed and oil extraction residues from sunflower seed, respectively, are of great significance. Sunflower seed does not contain anti-nutritive and toxical compounds. After crossing of species having a high oil content, the today cultivated sunflower hybrids bring seeds containing 17-22% crude protein and 30-52% oil. The cultivation also has led to a considerable reduction of the hull content. In processing of sunflower proteins colour problems occur resulting from finely ground particles of dark hulls and from polyphenolic acids which are easily oxidized and converted into brown polymerics. Essential components of the sunflower protein production are, therefore, the at least 98% dehulling before processing as well as the separation of polyphenolic acids and/or the prevention of their oxidation. In principle, the variation and combination of technological steps in pre-treating and defatting of sunflower seed, in extracting, precipitating, washing and drying of proteins, the chemical modification of proteins obtained, the interaction with neutral salts or complexing agents, and the admixture of lysine or proteins of high lysine content allow to adapt sunflower proteins to each type of application.     

Bioaccessibility of Ca,Mg, Mn and Cu from whole grain tea-biscuits: Impact of proteins,phytic acid and polyphenols

Levels of some essential minerals (Ca, Mg, Cu and Mn) were determined in ten different types of experimentally prepared hard biscuits. In relation to the wheat flour-based reference sample, other investigated samples were enriched with different ratios of integral raw materials of different origin or various dietary fibers in view of improving their functionality and nutritive quality. The goal of the research was to evaluate enriched biscuits as additional sources of calcium, magnesium, copper and manganese in nutrition and to investigate if the modifications of wheat flour based biscuit composition significantly change the amounts of total and bioaccessible minerals in the final product. Since our results indicated significant changes of mineral bioaccessibility among the samples, obtained results were correlated to the content of proteins, phytic acid and polyphenols for the sake of assessing their impact as limiting factors of mineral bioaccessibility in these types of foods.     

Preparation and characterization of a protein hydrolysate from an oilseed flour mixture

A novel protein hydrolysate was prepared from the mixture of oilseed flours (soybean, sesame and peanut) and determined physicochemical & functional properties along with comparison of individual oilseed flour hydrolysate of soybean. Mixed flour obtained from oilseed flours viz. soybean, sesame and peanut by using calculated amounts in the ratio of 1.1:1.7:0.7, respectively was used as a starting raw material having balanced amino acid profile. Protein hydrolysates were prepared from mixed flour and soybean flour by a double enzyme treatment method to a level of 40% degree of hydrolysis. The dried protein hydrolysate prepared from the mixed flour had 72% crude protein. This protein was characterized by gel filtration chromatography and SDS-PAGE. Comparison of the amino acid profile of the protein hydrolysate from mixed flours and soyabean flours showed a significant increase in the former one with respect to amino acid contents usually deficient of single oilseed flour hydrolysate. The product is creamish yellow in colour and had a solubility of >90% over a wide pH range of 2–10. The mixed flour protein hydrolysate showed better functional attributes such as foaming, as compared to that from soybean flour alone.     

自然发酵蔬菜制品中降解亚硝酸盐乳酸菌的分离与鉴定

以自然发酵蔬菜为原料,采用平板计数和钙溶圈法分离纯化菌株,并分析菌株的亚硝酸盐降解能力。结果表明,钙溶圈法分离的产酸能力较强的9株细菌,经生理生化鉴定均为乳酸菌。乳酸菌在MRS培养基中都具有亚硝酸盐分解能力,其中H12、L7和X1三株乳酸菌亚硝酸盐降解率高于89%,且降解速度较快,其中X1降解亚硝酸活性最强。乳酸菌X1还表现良好的产酸能力和耐盐性,经16S rDNA鉴定为植物乳杆菌(Lactobcillus plantarum)。     

腌制食品中降解亚硝酸盐的乳酸菌分离与鉴定

从多种传统腌制蔬菜中分离到12株乳酸菌,对它们的16S核糖体基因进行扩增测序,根据序列的同源性鉴定为植物乳杆菌（Lactobacillus plantarum）、沙克乳杆菌（Lactobacillus sakei）和戊糖片球菌（Pediococcus pentosaceus）。对其生化特征以及亚硝酸盐耐受性和降解能力进行了研究和比较,最终筛选出1株各项指标优良,且能快速降解亚硝酸盐的植物乳杆菌J-10,该菌降解亚硝酸钠的最适温度为37℃,最适pH值为6．2,在添加0．25mg／mL的亚硝酸钠的培养液中培养24h后,亚硝酸盐降解率为99．2％。     

Isolation,functional properties and potential use of protein preparations from lupin

Protein isolates were prepared by extraction with diluted NaOH (resulting the highest yield) and precipitation with HCl from lupin seeds grown in Egypt and Hungary. Protein content, amino acid composition, biological value and functional properties of isolates were studied. The proteins were high in lysine but relatively low in sulfur‐containing amino acids. Good solubility and moderate emulsifying, foaming and gel‐forming properties of isolates were observed. Enrichment of fruit‐ and vegetable‐based baby foods with these isolates resulted in products with excellent organoleptic properties and moderate biological value. Additional enrichment with small quantities of methionine increased significantly the biological value without any negative changes of organoleptic characteristics.     

Isolation, functional properties and potential use of protein preparations from lupin.

Protein isolates were prepared by extraction with diluted NaOH (resulting the highest yield) and precipitation with HCl from lupin seeds grown in Egypt and Hungary. Protein content, amino acid composition, biological value and functional properties of isolates were studied. The proteins were high in lysine but relatively low in sulfur-containing amino acids. Good solubility and moderate emulsifying, foaming and gel-forming properties of isolates were observed. Enrichment of fruit- and vegetable-based baby foods with these isolates resulted in products with excellent organoleptic properties and moderate biological value. Additional enrichment with small quantities of methionine increased significantly the biological value without any negative changes of organoleptic characteristics.     

Selective extraction,structural characterisation and antifungal activity assessment of napins from an industrial rapeseed meal

This article reports an extraction–purification of napins from an industrial rapeseed meal and the assessment of their antimicrobial activity against Fusarium langsethiae. The best extraction conditions are observed at pH 2, 12% (w/w) of rapeseed meal after 15 min of extraction in water at room temperature. Under these conditions the extraction is highly selective, allowing a simple purification process (ammonium sulfate precipitation followed by desalting size exclusion chromatography) to get purified napins. These napins possessed significant anti-Fusarium activity (IC₅₀ = 70 μM) and a compact secondary structure rich in α-helix, which may explain this bioactivity.     

Isolation and characterization of protein fractions from deoiled rice bran

Rice bran contains underutilised protein materials. Sequential extraction of rice bran protein (RBP) from defatted rice bran was conducted based on the differences in their solubility. Three extraction methods were investigated. Method 1 involved the isoelectric and acetone precipitation using water, 50 g kg⁻¹ NaCl, 0.02 mol L⁻¹ NaOH and 70% ethanol as extracting solvents for albumin (pH 4.1), globulin (pH 4.3), glutelin (pH 4.8) and prolamin, respectively. Method 2 adopted dialysis and sequential extraction was carried out with 20 g kg⁻¹ NaCl, 70% ethanol, 0.1 mol L⁻¹ acetic acid and 0.1 mol L⁻¹ NaOH solution as extracting solvents. Method 3 combined dialysis, isoelectric and acetone precipitation for the extraction. Based on the yields and data obtained from sodium dodecyl sulphate polyacrylamide gel electrophoresis, size-exclusion chromatography and differential scanning calorimetry, method 3 was chosen for the isolation and characterization of RBPs. Rice bran protein fraction (RBPF)—albumin, globulin, glutelin and prolamin were obtained in good yields. Denaturation temperature and enthalpy values of denaturation of RBPF vary. Highest phytate content was found in albumin and lowest in prolamin. The highest antioxidative and hemagglutinating activities were observed in albumin.     

果蔬酵素中优良酵母菌的分离、鉴定及耐受性研究

该研究采用传统培养分离技术从自然发酵的果蔬酵素中分离酵母菌,通过高糖、乙醇耐受性测定从中筛选优良菌株,采用形态观察、生理生化试验及分子生物学技术对其进行菌种鉴定,并对其低pH、高糖、乙醇及高温耐受性进行分析。结果表明,分离筛选得到一株优良酵母菌,编号为7-1-1,经鉴定,该菌株属于异常威克汉姆酵母（Wickerhamomyces anomalus）,其具有良好的耐受性,能在低pH（1.5）、高糖（900 g/L）的培养基上生长,可耐受体积分数为14%的乙醇和37 ℃的高温,可为果蔬发酵剂的开发奠定一定的基础。     

18株植物内生真菌的分离纯化及鉴定

植物内生真菌生活环境特殊、种类多,通过大量的分离和筛选得到有价值的内生真菌,可以为新型天然产物的获得提供更丰富的来源。本实验随机采摘了12种植物,采用组织分离法从中有选择性地分离纯化得到了18株内生真菌,通过28S r DNA序列测定和系统发育树分析,对18株真菌进行了鉴定。结果表明,这18株内生真菌主要属于Cladosporium,Paramicrothyrium,Mycosphaerella,Colletotrichum,Corynespora,Sarocladium,Guignardia,Phoma,Pseudocercospora,Collembolispora,Alternaria,Glomerella等属,说明了植物内生真菌的丰富多样性。得到的18株内生真菌中有3株不常见真菌和一株新真菌,其次级代谢产物值得进一步研究。      

Comparative analysis of cells and proteins of pumpkin plants for the control of fruit size

Common pumpkin plants (Cucurbita maxima) produce fruits of 1-2kg size on the average, while special varieties of the same species called Atlantic Giant are known to produce a huge fruit up to several hundred kilograms. As an approach to determine the factors controlling the fruit size in C.?maxima, we cultivated both AG and control common plants, and found that both the cell number and cell sizes were increased in a large fruit while DNA content of the cell did not change significantly. We also compared protein patterns in the leaves, stems, ripe and young fruits by two-dimensional (2D) gel electrophoresis, and identified those differentially expressed between them with mass spectroscopy. Based on these results, we suggest that factors in photosynthesis such as ribulose-bisphosphate carboxylase, glycolysis pathway enzymes, heat-shock proteins and ATP synthase play positive or negative roles in the growth of a pumpkin fruit. These results provide a step toward the development of plant biotechnology to control fruit size in the future.     

Isolation and purification of three antifungal proteins from sorghum endosperm

Three proteins potently inhibitory to the growth of Fusarium moniliforme, the grain mould pathogen have been identified from sorghum endosperm, using aqueous extraction, gel filtration and ion-exchange chromatography coupled with bioassay. The aqueous extract (Tris buffer, pH 6.8) of sorghum endosperm flour was separated into two fractions by passing through Sephadex G-50. The void volume fraction, showing antifungal activity was further fractionated by ion-exchange chromatography on SP Sephadex C-50. The most potent fraction was that which bound to the SP Sephadex column at pH 6.0. A less potent fraction with an 18 kDa protein as major component was released on shifting the pH to 8.5. The bound fraction at pH 8.5 was a much more potent inhibitor of fungal growth than the unbound fraction; and it was composed of two major polypeptides with molecular weights of 26 and 30 kDa. All three polypeptides were separated on SDS-PAGE gels, transferred onto Immobilon and tested for antifungal activity. The test showed that the 26 and 30 kDa proteins retained the antifungal activity even after electrotransfer. Antibodies raised against the electroeluted proteins were shown to abolish the antifungal activity of the endosperm extracts. These proteins appeared only in the endosperm of sorghum grains as revealed by dot immunobinding assay. The 26 and 30 kDa antifungal proteins were also present in pearl millet and maize, while the 18 kDa protein was found only in sorghum. Cross-reactivity of antibodies with the aqueous extracts of wheat, rice and ragi was not seen.     

泡菜中乳酸菌的分离、鉴定和生产初试

从泡菜汁中分离乳酸菌,筛选出3株产酸量较高、生长良好的菌株。从该菌的形态特征、菌落特征、生理生化特征进行鉴定,判定结果A8、B2为弯曲乳杆菌,B4为植物乳杆菌。以其为纯培养发酵剂制备萝卜泡菜,质量优于自然发酵产品。