Cloning, functional expression, and characterization of cystatin in sesame seed

A cDNA fragment encoding cystatin, a cysteine protease inhibitor, was obtained from maturing sesame seeds. The clone was constructed in a nonfusion or fusion vector and then overexpressed in Escherichia coli. The recombinant cystatins were found in the soluble fraction of cell extract and were demonstrated to be functionally active in a reverse zymographic assay. The corresponding endogenous 22 kDa cystatin of low abundance in mature seeds was purified to homogeneity via a papain-coupling affinity column and confirmed by western blotting with antibodies against the recombinant cystatin. Both endogenous and recombinant cystatin proteins showed effective inhibitory activities against papain with K(i) values of 7.89 x 10(-8) M and 2.77 x 10(-8) M, respectively. Immunodetection indicated that cystatin was specifically expressed in maturing seeds and rapidly degraded in germination. Accordingly, zymographic and inhibition analyses showed that sesame cystatin could not inhibit the de novo synthesized proteases in germinating seeds. It is suggested that sesame cystatin may play a role in the regulation of endogenous cysteine proteases during seed maturation and germination.     

Quantitation of the main constituents of some authentic sesame seed oils of different origin

This paper describes the composition of sesame seed oils obtained from seeds collected from five countries that are major suppliers of traded sesame seed oil. Oils were extracted from the seeds using small-scale industry pressing equipment and analyzed using standard methods for fatty acids, fatty acids in the triglyceride 2-position, tocopherols and tocotrienols, triglycerides, sterols, steradienes, and iodine value. Values for the composition of the sterols, triglycerides, fatty acids, iodine value, and tocopherol composition were generally in good agreement with the results published elsewhere. All of the oils from roasted seeds contained low levels of the sterol degradation products stigmasta-3,5-diene and campesta-3,5-diene, which were probably formed by dehydration of the parent sterols during roasting.     

稻蟹生态种养模式优质食味粳稻的稻米营养品质分析

本研究选用优质食味粳稻品种‘辽粳433’和‘五优稻4号’(稻花香2号)为材料,设置了稻蟹生态种养(ecological rice-crab, ERC)和水稻单植(rice monoculture, RM)2个模式,测定与稻米品质相关的蛋白质含量、直链淀粉含量和矿物质元素含量,采用非靶向代谢组学方法分析两个模式之间与营养相关的差异代谢产物,从多个方面分析稻蟹生态种养的稻米营养品质,为稻蟹生态种养模式的应用推广提供理论依据。结果表明,与RM相比, ERC的‘辽粳433’和‘五优稻4号’糙米蛋白质含量显著降低6.75%和10.11%, Fe含量显著增加,为RM的2.03倍和4.99倍, Se含量显著增加,为RM的3.11倍和5.74倍, Pb含量显著降低35.11%和44.35%。采用GC-MS检测到233种代谢产物,利用偏最小二乘法(PLS-DA)分析发现, ERC和RM糙米的代谢产物差异显著,ERC诱导‘辽粳433’和‘五优稻4号’的4-氨基丁酸显著上调为RM的2.11倍和11.99倍,抗氧化性物质α-生育酚、β-羟肉豆蔻酸以及奎宁酸分别显著上调为RM的1.62倍和2.22倍、12.64倍和20.48倍以及14.25倍和4.67倍,己糖醇显著上调为RM的14.36倍和15.14倍,半乳糖醇显著上调为RM的3.13倍和2.87倍。此外, ERC的‘辽粳433’产量降低286.0 kg·km~(-2),‘五优稻4号’产量增加344.5 kg·km~(-2),均与RM差异不显著。综上所述,稻蟹生态种养模式在稳产的基础上可以增加优质食味粳稻稻米的营养价值。     

Nutritional evaluation of tepary bean: Elemental analysis of seed

Tepary bean (Phaseolus acutifolius var. latifolius), a potential arid‐land legume crop, was analyzed for total protein, oil, fiber and mineral content. Results indicate the bean would be adequate in these nutrients for a human diet if deficient amino acids in the seed‐protein were complimented.     

冷榨工艺对芝麻油和芝麻饼品质的影响

为比较芝麻不同压榨工艺对芝麻油和芝麻饼品质的影响,分别以带皮和脱皮白芝麻为原料,采用液压榨油机进行冷榨,对所得芝麻油和芝麻饼进行品质分析,并与热榨芝麻油、芝麻饼以及芝麻油国家标准进行对比。结果表明：冷榨芝麻油的色泽、酸价、过氧化值等质量指标都明显优于热榨芝麻油和芝麻香油国家标准;脱皮冷榨芝麻油较整籽冷榨芝麻油的酸价降低,但过氧化值有所升高;冷榨芝麻油较热榨芝麻油的VE含量、芝麻酚含量明显降低,芝麻素含量有所升高,氧化诱导时间明显缩短;脱皮冷榨芝麻油较整籽冷榨芝麻油的生育酚含量降低,芝麻素和芝麻酚含量有所升高,氧化诱导时间稍有延长。脱皮冷榨芝麻饼粗脂肪含量16.63%、粗蛋白含量54.09%、蛋白质溶解度NSI为23.50%。芝麻冷榨不仅可以得到色浅清亮的清香芝麻油,还可以得到蛋白质含量高且功能性好的食用芝麻蛋白。     

Characterization of a calcium-soluble protein fraction from yellow mustard (Sinapis alba) seed meal with potential application as an additive to calcium-rich drinks

A calcium-soluble protein isolate (CSPI) was prepared from the supernatant obtained after addition of 0.75 M calcium chloride to a pH 5.0 aqueous extract of yellow mustard (Sinapis alba) seed meal. Total amino acid analysis showed that the CSPI has significantly higher (p < 0.05) contents of glutamic acid + glutamine, cysteine, and proline when compared to the precipitated, calcium-insoluble proteins. Peptide mass fingerprinting of tryptic peptides of the major polypeptides by mass spectrometry indicated that the CSPI is composed mainly of cruciferin proteins with a contribution from napins (the major allergenic proteins of S. alba). The S. alba CSPI had significantly higher (p < 0.05) protein solubility and emulsion formation ability in the presence of 0.75 M calcium chloride when compared to similar isolates prepared from Brassica juncea (brown mustard) and soybean seed meals. We suggest that the S. alba CSPI could be used to prepare calcium-fortified high protein liquid products. However, the presence of allergenic proteins in this extract may limit its widespread food use.     

Nutritional responses of rats to diets based on chickpea ( Cicer arietinum L.) seed meal or its protein fractions

The aim of this study was to isolate the protein fractions from chickpea, var. IAC-Marrocos, as well as to evaluate its in vivo nutritional protein quality. Among the proteins, albumins showed better nutritional value in the in vivo assays and amino acid contents, despite their higher trypsin inhibitor contents. Trypsin inhibitors were found to be heat labile in all samples, but the digestibility results for unheated and heated flour and albumins suggest that their contents are not very decisive. The PER values for casein (not supplemented) were very similar to those of heated flour and unheated or heated albumin and total globulins. The albumin and glutelin fractions showed the best results for PDCAAS, however, lower than those of casein. Despite the high digestibility of the globulin the very low essential amino acid content lowered its PDCAAS, and it had the lowest values.     

不同压榨工艺对芝麻油和芝麻饼品质的影响

为比较芝麻不同压榨工艺对芝麻油和芝麻饼品质的影响,分别以整籽带皮白芝麻和整籽脱皮白芝麻为原料,采用液压榨油机进行冷榨,对所得芝麻油和芝麻饼进行品质分析,并与热榨芝麻油、芝麻饼以及芝麻油国家标准进行对比.结果表明:冷榨芝麻油的色泽、酸价、过氧化值等质量指标都明显优于热榨芝麻油和芝麻香油国家标准;脱皮冷榨芝麻油较整籽冷榨芝...     

Antioxidant activity of extracts of black sesame seed (Sesamum indicum L.) by supercritical carbon dioxide extraction

Antioxidant activities of extracts derived from sesame seed by supercritical carbon dioxide (SC-CO(2)) extraction and by n-hexane were determined using alpha,alpha-diphenyl-beta-picylhydrazyl (DPPH) radical scavenging and linoleic acid system methods. The highest extracted yield was given at 35 degrees C, 40 MPa, and a CO(2) flow rate of 2.5 mL min(-1) by an orthogonal experiment. The yields of extracts increased with increasing pressure, and yields at 40 and 30 MPa were higher than that by solvent extraction at 46.50%. Results from the linoleic acid system showed that the antioxidant activity follows the order: extract at 35 degrees C, 20 MPa > BHT > extract at 55 degrees C, 40 MPa > extract at 55 degrees C, 30 MPa > Trolox > solvent extraction > alpha-tocopherol. The SC-CO(2) extracts exhibited significantly higher antioxidant activities comparable to that by n-hexane extraction. The extracts at 30 MPa presented the highest antioxidant activities assessed in the DPPH method. At 20 MPa, the EC(50) increased with temperature, which indicated that the antioxidant activity was decreased in a temperature-dependent manner. The significant differences of antioxidant activities were found between the extracts by SC-CO(2) extraction and n-hexane. However, no significant differences were exhibited among the extracts by SC-CO(2) extraction. The vitamin E concentrations were also significantly higher in SC-CO(2) extracts than in n-hexane extracts, and its concentrations in extracts corresponded with the antioxidant activity of extracts.     

鸡蛋壳膜角蛋白不同提取工艺的效果比较

为探索不同方法提取的鸡蛋壳膜角蛋白的得率及其结构的区别,为鸡蛋壳膜角蛋白工业化生产方法的选择提供理论依据,分别采用氢氧化钠碱法、过氧化氢氧化法、碱性蛋白酶法从鸡蛋壳膜中提取角蛋白,以其反应速率及产品角蛋白的得率、分子量、结构完整性等为指标,比较3种不同提取方法对鸡蛋壳膜角蛋白性质的影响。试验比较结果表明,角蛋白得率：氧化法(24.33%)＞碱法(19.31%)＞酶法(15.19%);反应速率：氢氧化钠碱法最快,过氧化氢氧化法次之,碱性蛋白酶法最慢;角蛋白分子量：碱性蛋白酶法(31～43 kDa)＞氢氧化钠碱法(14.4～20.1 kDa)＞过氧化氢氧化法(＜14.4 kDa);角蛋白结构：碱性蛋白酶法和氢氧化钠碱法提取的角蛋白,二级结构保存完整,过氧化氢氧化法提取的角蛋白二级结构受到了破坏。氢氧化钠碱法和碱性蛋白酶法可用于生产分子量高、二级结构完整的角蛋白产品,而过氧化氢氧化法是生产小分子肽类角蛋白产品较好的方法。     

Preparation and characterization of papain-modified sesame (Sesamum indicum L.) protein isolates

Defatted sesame meal ( approximately 40-50% protein content) is very important as a protein source for human consumption due to the presence of sulfur-containing amino acids, mainly methionine. Sesame protein isolate (SPI) is produced from dehulled, defatted sesame meal and used as a starting material to produce protein hydrolysate by papain. Protein solubility at different pH values, emulsifying properties in terms of emulsion activity index (EAI) and emulsion stability index (ESI), foaming properties in terms of foam capacity (FC) and foam stability (FS), and molecular weight distribution of the SPI hydrolysates were investigated. Within 10 min of hydrolysis, the maximum cleavage of peptide bonds occurred as observed from the degree of hydrolysis. Protein hydrolysates have better functional properties than the original SPI. Significant increase in protein solubility, EAI, and ESI were observed. The greatest increase in solubility was observed between pH 5.0 and 7.0. The molecular weight of the hydrolysates was also reduced significantly during hydrolysis. These improved functional properties of different protein hydrolysates would make them useful products, especially in the food, pharmaceutical, and related industries.     

Influence of P,Zn and Fe fertilization upon yield and protein quality of Sanilac Navy bean seed

Abstract

Treatments of P, Zn and Fe fertilizers were added to a Zn deficient Wisner silty clay loam soil. Sanilac bean plants were grown as the Zn responsive test crop and tissue samples were taken 5 weeks after planting for early growth and Zn uptake responses. At maturity, yield data were obtained and composite samples of beans were taken for determination of protein quality as evaluated by percentage of N, percentage of crude protein and relative contents of essential amino acids. A growth and Zn uptake response was obtained to ZnSO₄, ZnNTA and FeNTA fertilization at both P levels, while a yield response to the same treatments was obtained only at high soil P (448 kg/ha) levels. The percentage N, percentage crude protein and relative contents of essential amino acids did not change as a result of P, Zn or Fe fertilization even when yields were tripled due to Zn fertilization.     

Nutritional and physiological responses of young growing rats to diets containing raw cowpea seed meal,protein isolate (globulins), or starch

The nutritional and physiological effects of raw cowpea (Vigna unguiculata (L) Walp.) seed meal, protein isolate (globulins), or starch on the metabolism of young growing rats have been evaluated in 14-day trials. Wet and dry weight gain, feed conversion efficiency, and lipid and protein accretion were significantly reduced as a result of inclusion of seed meal, globulins, or starch in the diet, with growth retardation being most marked with the seed meal. The proportional weights of the small intestine and pancreas were increased by meal diets, and serum cholesterol levels were slightly reduced. The globulins and raw starch also increased relative small intestine weights but had no effect on the pancreas or serum constituents. The effects of cowpeas on rats appeared to be due primarily to the combined actions of globulins, resistant starches, protease inhibitors, and possibly fiber and non-starch polysaccharides on intestinal and systemic metabolism.     

Molecular cloning of 11S globulin and 2S albumin, the two major seed storage proteins in sesame

Insoluble 11S globulin and soluble 2S albumin, conventionally termed alpha-globulin and beta-globulin, are the two major storage proteins and constitute 80-90% of total seed proteins in sesame. Two full-length cDNA clones were sequenced and deduced to encode sesame 11S globulin and 2S albumin precursors, respectively. Deduced amino acid composition reveals that 2S albumin, but not 11S globulin, is a sulfur-rich protein. Three abundant polypeptides of 50-60 kDa were resolved on SDS-PAGE when seed-purified 11S globulin was prepared in nonreducing conditions. Immunological analysis suggests that these three polypeptides are encoded by homologous genes. Immunodetection on the overexpressed protein of the 11S globulin clone in Escherichia coli indicates that this clone encodes the precursor protein of one of the three purified 11S globulin polypeptides.     

Gene families encoding isoforms of two major sesame seed storage proteins, 11S globulin and 2S albumin

Sesame (Sesamum indicum L.) seed has been recognized as a nutritional protein source owing to its richness in methionine. Storage proteins have been implicated in allergenic responses to sesame consumption. Two abundant storage proteins, 11S globulin and 2S albumin, constitute 60-70 and 15-25% of total sesame proteins, respectively. Two gene families separately encoding four 11S globulin and three 2S albumin isoforms were identified in a database search of 3328 expressed sequence tag (EST) sequences from maturing sesame seeds. Full-length cDNA sequences derived from these two gene families were completed by PCR using a maturing sesame cDNA library as the template. The amino acid compositions of these deduced storage proteins revealed that the richness in methionine is attributed mainly to two 2S albumin isoforms and partly to one 11S globulin isoform. The presence of four 11S globulin and three 2S albumin isoforms resolved in SDS-PAGE was confirmed by MALDI-MS analyses. The abundance of these isoforms was in accord with the occurrence frequency of their EST sequences in the database. A comprehensive understanding of these storage proteins at the molecular level may also facilitate the identification of allergens in crude sesame products that have caused severe allergic reactions increasingly reported in the past decade.     

Effect of seed rate and nitrogen fertilizer on weed species composition,density and diversity in two sesame varieties

To evaluate the effect of seed and nitrogen rates on weed species composition, density, biomass and diversity in two sesame (Sesamum indicum L.) varieties, a field experiment was conducted in 2009, 2010 and 2011 rainy seasons at Samaru, Nigeria. Four seed rates, 2, 4, 6 and 8 kg ha^?1, four nitrogen rates, 0, 30, 60 and 90 kg N ha^?1 and two sesame varieties NCRIBEN 01M and E8 were arranged as factorial in a split plot design. Weeds with the highest important values in sesame field were Dactyloctenium aegyptium, Ludwigia decurrens, Ageratum conyzoides and Cyperus esculentus. Year had a significant effect on weed density, biomass, diversity, evenness and richness. Weed density, biomass, diversity and richness were lowest in the 2011 trial and weed species evenness in 2009. Variety E8 reduced weed biomass better than NCRIBEN 01M. Averaged over years, weed diversity and evenness were lowest at 4 kg seeds ha^?1. Seed × nitrogen rates effect of 4 kg seed ha^?1 and 30 kg N ha^?1 produced the lowest weed species diversity and evenness. The result suggests that variety E8 at 4 kg seed ha^?1 and 30 kg N ha^?1 with hoe weeding at 3 and 6 WAS may provide better weed control, and it is recommended in sesame production.     

Structural features of arabinoxylans extracted with water at different temperatures from two rye flours of diverse breadmaking quality

The water extractable (WE) arabinoxylans from two rye flours differing in baking quality were studied following sequential extraction with water at 4, 40, and 100 degrees C. Ammonium sulfate fractionation of the resulting WE fractions and subsequent analysis revealed substantial differences in the structure of the isolated materials. Furthermore, it allowed us to identify the factors contributing to arabinoxylan water extractability. Our results provide compelling evidence for the existence of separate polymers in rye WE arabinoxylans with different substitution degrees, ranging from quantitatively dominating, lowly substituted populations (arabinose to xylose ratio, Ara/Xyl approximately 0.5) to comparatively less abundant, highly substituted analogues (Ara/Xyl approximately 1.3). Generally, arabinoxylan water extractability was governed by the relative proportion of lowly and highly branched structures. A gradually increasing proportion of highly substituted populations was observed from cold to hot WE fractions. This was associated with the lower proportion of monosubstituted xylopyranosyl residues in the backbone, the higher proportion of disubstituted xylopyranosyl residues, and the higher level of substitution with feruloyl residues. Notable differences in the ratio of phenolic compounds to arabinose residues were observed between corresponding polymers isolated from rye flours of high and low baking quality, whereas the differences in their molecular weights were much less pronounced.