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排序方式: 共有272条查询结果,搜索用时 15 毫秒
1.
Johann Vollmann Heinrich Grausgruber Helmut Wagentristl Heinrich Wohleser Pavel Michele 《Journal of the science of food and agriculture》2003,83(15):1581-1586
The presence of protease inhibitors in soybean prohibits the utilisation of the raw beans for food and feed. However, little information is available about environmental influences and the effects of nitrogen and sulphur supply on the antinutritional constituents of soybean. As these factors may influence protease inhibitors, soybean genotypes segregated according to the presence or absence of the Kunitz trypsin inhibitor have been evaluated for trypsin inhibitor activity (TIA) in field trials. TIA was affected significantly by environment (geographical location), fertilisation treatment and genotype. Environmental means of TIA were between 69.5 and 104.8 mg g?1. Nitrogen application, which caused an increase in seed protein content, resulted in a reduction in TIA by about 15% as compared with the control. Remarkably, simultaneous application of nitrogen and sulphur in the form of ammonium sulphate had a similar reductive effect on TIA to that of nitrogen application alone, although soybean protease inhibitors are rich in sulphur amino acids. Significant genetic variation in TIA was found both within the genotype class with the Kunitz inhibitor present as well as within the class lacking this inhibitor. The results suggest that TIA of soybean may be modified considerably by genetic improvement and appropriate agronomic management. Copyright © 2003 Society of Chemical Industry 相似文献
2.
Soybean plant volatiles, extracted as steam distillates, significantly affected the behavior and biology of the cabbage looper,Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae). Distillates from the susceptible Davis variety attractedT. ni larvae and female adults, whereas those from resistant PI 227687 plants repelled them. When mixed in an artificial diet, steam distillates from PI 227687 plants caused mortality of first-instar larvae. Adults emerging from pupae topically treated with 5 g of such PI 227687 extractable showed developmental abnormalities. Larval feeding was significantly less on Davis leaves treated with PI 227687 volatiles as compared to solvent (acetone) or such Davis extractables. However, Davis volatiles on PI 227687 leaves did not increase larval feeding. HPLC analyses of steam distillates from susceptible Davis versus resistant PI 227687 indicated differences. 相似文献
3.
The influence of cobalt on the electrodeposition of zinc onto AISI 1018 steel was studied in weakly alkaline glycine solutions. Thermodynamic calculations were performed to construct predominance-zone diagrams to identify the stability of the zinc and cobalt glycine complexes, and experimental studies of electrochemical behavior and deposit properties were conducted. When zinc is present, cobalt deposition shifts to more negative potentials, producing ZnCo alloys. Two main reduction steps were observed for electrodeposition from the ZnCo bath: the first at low potentials was due to ZnCo electrodeposition. In the second, at more negative potentials, cobalt content in the deposit increased forming a range of intermediate phases, and the hydrogen-evolution reaction became significant. The presence of Co(II) in the bath modified the morphology of the deposits as well as reducing the faradaic metal-deposition efficiency. ZnCo-deposit morphology was modified by the applied current density as well as the metal composition of the coating. X-ray diffraction studies revealed that cobalt oxide or hydroxide is formed during ZnCo electrodeposition, indicating that an elevation of the interfacial pH plays a role in the alloy deposition process. 相似文献
4.
Rodríguez CE Arranz JA Colomé N Bech-Serra JJ Canals F Del Toro M Riudor E 《Proteomics. Clinical applications》2009,3(12):1430-1439
A variant phenotype of nonketotic hyperglycinemia has been described by our group associated with pulmonary hypertension. The aim of this study is to investigate the cerebrospinal fluid proteomes to get an insight into this neurodegenerative process producing leukoencephalopathy with white matter spongiform degeneration. DIGE and MALDI-TOF-TOF analyses were performed to carry out the proteomic study of four patients against three normal controls and one additional control of a classical nonketotic hyperglycinemia. The differential proteomic analysis showed a displacement of some series of spots toward the acidic side. The shifted proteins showed a high degree of carbonylation and increased methionine sulfoxidation was found in cystatin C and in vitamin-D-binding protein. These findings in addition to the increase of serum malondialdehyde concentration provide evidence of an oxidative stress in the patients under study, which is probably systemic rather than mainly confined to the CNS. The similarities of our findings with those found in other neurodegenerative diseases suggest that oxidative damage is commonly involved in these pathologies. DIGE technology improves the 2-D PAGE differential analysis and it is suitable in proteomic studies with a small number of cases. 相似文献
5.
R. F. Wilson W. P. Novitzky G. P. Fenner 《Journal of the American Oil Chemists' Society》1995,72(12):1425-1429
Fungal damage caused by pathogens such asFusarium, Cercospora, andPhomopsis can have a devastating impact on physical quality and farm price of soybeans. In some price-discount schedules, soybeans
may be rejected with as low as 5% fungal damage. Although the severity of this problem varies throughout the United States,
millions of bushels of fungus-damaged soybeans may be destroyed annually due to a lack of markets. The effect of fungal damage
on seed composition was evaluated to assess potential utility of highly damaged soybeans. Graded samples of the cv. Centennial
soybean were dried to 10% moisture and blended on a proportional weight basis to derive a series of treatments from 0 to 80%
fungal damage. A positive correlation was found between fungal damage and both protein and oil concentrations. This condition
was attributed to loss of residual seed mass. As a result, the protein concentration of defatted meal increased from ca. 54
to 66% over the range of 0 to 80% fungal damage. Mycotoxin contamination appeared to be insignificant in these high-protein
meals. Fixed colors in bleached, alkali refined oils were intensified by heat treatment prior to extraction. No significant
differences, however, were noted in total polar lipid content, phospholipid, or tocopherol composition among treatments of
up to 20% fungal damage. Oils from treatments of more than 40% fungal damage were more severely oxidized and could not be
degummed effectively. These data suggest that fungus-damaged soybeans may be blended with high-quality soybeans to alleviate
the chemical symptoms associated with unacceptable product quality. Thus, through various blend ratios, processors may consider
using fungus-damaged soybeans to gain economic advantage, especially when high-quality soybeans have lower protein concentration. 相似文献
6.
迟永祥 《四川大学学报(工程科学版)》1997,(3)
本文介绍了一种先进的甘氨酸合成工艺,产品产率达85%,纯度大于98%,并采用正交设计优化实验方案。实验证明,本工艺与国内现行工艺相比,具有收率高,生产周期短,后处理简单等优点,有较高的工业价值 相似文献
7.
8.
Simulation results for continuous vacuum evaporation crystallization obtained by Aspen Plus and experimental results for semi‐batch vacuum evaporation crystallization are presented. In the crystallization experiments, the fixed heat duty was used to compare the water evaporation rates and crystal properties obtained at different pressures. The solution selected was aqueous glycine. It has the ability to form a number of different crystalline polymorphs, which allows it to exhibit a variety of different physical properties while maintaining its chemical properties. X‐ray diffraction results demonstrated that mainly the γ‐crystal form is produced under the conditions applied in vacuum evaporation crystallization. 相似文献
9.
目前,草甘膦的工业生产方法主要有甘氨酸法和亚氨基二乙酸(IDA)两种,我国主要以甘氨酸法为主,而国外则主要以亚氨基二乙酸法为主。介绍了该两种生产工艺在我国的合成研究进展,并指出了其在我国的发展前景。 相似文献
10.
Márcio de Barros Gabriela Alves Macedo 《Journal of the American Oil Chemists' Society》2015,92(1):37-45
Alkaline esterase (carboxylic‐ester hydrolases; EC 3.1.1.1) extracted from germinated soybean seeds (Glycine max) was purified approximately 3.6 times by chromatography in a DEAE‐cellulose anion exchange column and filtration in Sephadex G100 gel. The molecular mass of the enzyme was estimated at 45 kDa by gel electrophoresis (SDS‐PAGE). The purified enzyme showed a specific activity of 5.6 U mg?1 using p‐nitrophenyl butyrate as substrate. The esterase showed optimal activity at 47 °C in moderately alkaline pH, low stability in temperatures higher than 50 °C, and high stability at pH values between 6 and 9.5. The Ca2+ and Co2+ ions proved to have a positive effect on enzyme activity; however, Hg2+ completely inhibited esterase activity. Using p‐nitrophenyl butyrate as substrate, the enzyme showed a Km of 0.39 mM, Vmax of 31.5 mM mg?1 min?1 and kcat 7.60 × 106 s?1. Regarding substrate affinity, the enzyme showed greater activity for substrates containing short‐chain fatty acids, especially p‐nitrophenyl acetate. Such characteristics give the enzyme great potential for application in the production of low molecular weight esters, in the food industry, and in chemical products. This enzyme is another new member of the family of lipases and esterases from vegetable seeds with high activity and stability in alkaline pH. 相似文献