Effect of cooking on cowpea protein fractions

Nine cowpea cultivars obtained from Wad Medani Research Station were used in this study. The variation in protein fraction was: albumins 4.0–12.0, globulins 65.6–79.7, prolamins 1.4–2.2, G₁-glutelins 0.9–3.0, G₂-glutelins 1.4–2.9. G₃-glutenins 9.1–14.0 and insoluble protein 0.5–3.0%. Two cowpea cultivars, H8-14 and CB-46, selected for their high albumin content, were cooked in 150 ml of boiling distilled water under reflux for 45 minutes. The protein fractions in the cooked seeds were determined. Results indicated that albumin and globulin fractions decreased significantly (p0.05) for both cultivars after cooking. This decrease was accompanied by a significant increase in G₃-glutelin fractions.     

Changes in carbohydrate and nitrogenous components and amylase activities during germination of grain amaranth

Grain amaranth (Amaranthus hypochondriacus), Yercaud local variety, was soaked overnight and germinated for 192 h taking the soaked grains as the zero time (0 h) sample. The changes in the activities of - and -amylases, starch, sugar, protein and lysine contents during germination are reported. Activity of -amylase was high in the 0 h soaked grains, while -amylase activity was high in 72 h germinated grains. The joint action of the amylases resulted in a decrease of starch content from 0 to 192 h in germinated grains and an increase in total sugars during the initial period of germination.Protein nitrogen was found to decrease from 48 h to 192 h accompanied by an increase in free amino acid and non-protein nitrogen contents. Total lysine content was found to be increased by 31% in 24 h germinated grain amaranth. Protein fractionation of raw, soaked and 24 h germinated grain amaranth showed that the distribution of different types of proteins varied during germination of the grains. An increase of water soluble protein content was noticed in 24 h germinated grains.     

Amino acid compositions of different protein fractions in developing grains of NP 113 barley and its high lysine Notch-2 mutant

The percent distributions of protein fractions namely albumin + globulin, prolamine and glutelin were studied in developing grains of NP 113 barley and its high lysine mutant Notch-2. During development the percentage of albumin + globulin fraction decreased in NP 113, while those of prolamine and glutelin remained unchanged. The increase in prolamine was substantial from 24 to 31DAA. In Notch-2 the trend followed by albumin + globulin and prolamine was like that in NP 113, while the glutelin fraction showed an increase as compared to 10 DAA. The percent of albumin + globulin was slightly higher in Notch-2 as compared to NP 113. The absolute amount (mg/grain) of all the protein fractions increased during development in both NP 113 and its mutant Notch-2. During the grain development the prolamine content was substantially lower in the mutant than in the parent NP 113. The albumin + globulin content per endosperm was in general also higher in NP 113 than Notch-2. Amino acid analysis of the protein fractions did not reveal significant changes in lysine between NP 113 and Notch-2. Thus, the improvement in lysine in the mutant is primarily due to reduced synthesis of the prolamine fraction and not due to an increase in lysine in the mutant hordein fraction. Part of the improvemenht in lysine may also be due to increase in the percentage of albumin + globulin fractions which is lysine rich.Part of the Ph.D thesis submitted by S. Joshi to P.G. School, IARI, New Delhi.     

不同有机物料对苏打碱化土有机碳库和化学性质的影响

以内蒙古河套灌区苏打碱化土为研究对象开展田间试验,设置常规施肥(CK)、生物炭+常规施肥(BC)、牛粪+常规施肥(CD)、玉米秸秆+常规施肥(SW)和羊粪+常规施肥(GM)5个处理,研究不同有机物料添加对碱化土壤有机碳(SOC)库和化学性质的影响。分别于2019年和2020年收获季采集0—30 cm耕层土壤,分析不同有机物料添加下SOC及其活性碳组分和主要盐碱指标的变化特征及其相关关系。结果表明:与CK相比,2019年和2020年各有机物料添加处理下SOC平均增幅分别为22.7%和17.2%,土壤有机碳储量(SOCs)平均增幅分别为22.9%和18.2%;4种有机物料均提高了碱化土壤活性有机碳组分含量,其中,CD和GM处理下各活性碳组分含量增幅较其他处理更高;2019年各有机物料添加处理下碳库管理指数(CPMI)较CK提高53.8%~108.3%,2020年提高71.3%~144.1%(P＜0.05),CD和GM对CPMI的提升作用更明显。土壤化学性质方面,2020年各有机物添加处理下pH均显著下降,BC和CD处理下碱化度(ESP)分别显著下降36.9%和29.3%,CD处理下蔗糖酶活性提高36.7%(P＜0.05)。主成分分析(PCA)表明,影响苏打碱化土SOC含量变化的主要因素为活性有机碳组分和ESP。牛粪和羊粪施用对苏打碱化土有机碳库质量提升作用较好,生物炭施用对盐碱化指标改良效果最明显。     

长期不同施肥稻田土壤的氮素形态及矿化作用特征

利用稻田长期定位试验点的土壤样品,研究不同施肥稻田土壤的氮素形态及矿化作用特征.采用酸水解-蒸馏法测定土壤酸解总氮(TAHN)及其各组分含量;淹水密闭培养法测定土壤净矿化氮量(NMN).结果表明:①稻田土壤TAHN是全氮(TN)的主体(64%～73%),各施肥处理均显著提高其含量.单施无机肥处理对微生物量氮(MBN)、氨基酸氮(AAN)、酸解铵态氮(AN)、氨基糖氮(ASN)和酸解未知氮(HUN)的含量影响不大;无机配施有机肥显著提高各形态氮的含量;无机配施秸秆处理显著提高MBN、AAN、AN的含量.②14周的淹水密闭培养中,各施肥处理土壤NMN均随培养时间的延长而逐渐增加,矿化速率于培养3、4周后分别达到最大值.无机配施有机肥或秸秆处理土壤氮的矿化量、矿化率及矿化速率均高于单施无机肥处理.③相关性分析表明:土壤NMN与TN、TAHN、MBN存在极显著正相关关系;NMN与TAHN中各组分均存在正相关关系.进一步作多元回归分析表明:随着土壤氮矿化作用的增强,AAN和HUN的贡献增大,MBN对氮矿化也有重要的贡献.     

Copper Dynamics in a Typic Hapludalf Under Rice-Wheat Cropping System After Twelve Years of Annual Lantana Camara L. Residue Incorporation

Long term effects of lantana (Lantana camera L.) residue and fertilizer application were studied on copper (Cu) fractions in a Typic Hapludalf under rice-wheat cropping at Palampur, India (32°6′N, 76°3′E). A partitioning of soil Cu revealed residual Cu and organically bound Cu as the most dominant fractions followed by Cu occluded by free oxides, specifically exchangeable Cu and soil solution and exchangeable Cu. Continuous incorporation of lantana after 12 years resulted in redistribution of Cu from non-available forms to readily and potentially available forms in soil. All the Cu fractions were positively interrelated amongst themselves and with grain yield and Cu uptake in rice and wheat crops. Specifically exchangeable Cu followed by organically bound Cu were the most important Cu fraction contributing towards grain yield and Cu uptake in rice and wheat crops.     

运用简单线性水库模型计算Pothwar黄土平原（巴基斯坦）磷灰石损失情况

Apatite is the dominant phosphorus （P） mineral in early stages of soil development, and its redistribution as labile forms under pedogenesis controls terrestrial bioavailability. Quantitative distribution of labile forms of P and apatite-P was examined in Pothwar Loess Plain, Pakistan where the degree of pedogenesis varied with relief. Four soil types, Typic Ustorthents （Rajar）, Typic Calciustepts （Missa）, Udic Calciustepts （Basal）, and Udic Haplustalfs （Guliana）, were sampled from three replicated locations at genetic horizon level. With the exception of total P value at surface, the mean total and apatite-P decreased towards the surface in Udic Haplustalfs and Udic Calciustepts where dicalcium and octacalcium phosphate increased toward surface. Iron （oxides and oxyhydroxides） adsorbed and occluded P forms were also in greater quantities in Udic Haplustalfs and increased toward the surface, whereas they were lowest and uniform in the Typic Ustorthents. Aluminum- and organic P correlated with soil organic matter. Apatite-P decreased exponentially with an increase in the sum of iron adsorbed and occluded P fractions, and fitted the equation M（x） =M0[1 - exp（-wx）] with r^2=0.996, where M（x） is the mean apatite-P concentration in solum, M0 is the apatite-P content in the loess sediments, x is the cumulative iron adsorbed and occluded P, and w is an empirical factor indicating the change rate of apatite-P in the loess. From the calculated apatite-P of 740 mg kg^-1 at the time of deposition, mean apatite-P loss was 60% in Udic Haplustalfs, 33% in Udic Calciustepts, 23% in Typic Calciustepts, and 8% in Typic Ustorthents. The transformation of soil P to labile forms was faster and deeper in level or slight depressions followed by gently sloping areas in wide plains, and was the least in the gullied land.     

Effect of heat on rheology of gluten fractions from flours with different bread-making quality

Flours from wheat varieties of differing bread-making quality were fractionated using a sequential salt precipitation technique. The gluten fractions in the different varieties varied in the proportion of HMW, LMW glutenins and gliadins. Their rheological behaviour was examined using constant strain (2%) small deformation oscillation tests over frequencies ranging from 0.005 to 10 Hz, before and after heating at 90 °C. The fractions containing a higher proportion of HMW glutenins were associated with a predominantly elastic character, whereas fractions containing mostly gliadins exhibited a viscous-like behaviour. The frequency dependent rheological behaviour of fractions containing HMW proteins was less susceptible to heat, and their elastic character was maintained after heating, whereas the rheology of intermediate fractions and fractions containing mostly gliadins was more susceptible to heating, indicating a rapid change from viscous to elastic behaviour after heating.