Optimisation of microwave digestion for determination of Fe,Zn, Mn and Cu in various legumes by flame atomic absorption spectrometry

Fe, Zn, Mn and Cu levels in three Turkish legumes, kidney bean (Phaseolus vulgaris L.), lentil (Lens esculenta) and chickpea (Cicer arietinum), were determined by flame atomic absorption spectrometry. Dissolution conditions in the microwave‐assisted wet digestion method were studied by investigating several variables, including type of acid mixture, acid volume, digestion time, microwave power input and sample weight. Comparison with conventional wet acid digestion was also made. In order to check the element losses during digestion and the accuracy of the results, all tests were repeated after the addition of a spiked standard element solution to the legume sample. The microwave‐assisted digestion procedure optimised for kidney bean was adapted for lentil and chickpea. Fe, Zn, Mn and Cu concentrations (mg per 100 g sample) were determined in kidney bean as 6.27 ± 0.94, 2.23 ± 0.36, 1.64 ± 0.14 and 0.99 ± 0.19, in lentil as 8.24 ± 1.11, 2.46 ± 0.06, 1.17 ± 0.19 and 1.01 ± 0.28 and in chickpea as 6.00 ± 1.40, 2.21 ± 0.14, 1.60 ± 0.43 and 0.58 ± 0.18 respectively. Copyright © 2005 Society of Chemical Industry     

Methods to Characterize Ricin for the Development of Reference Materials

Ricin is an abundant protein from the castor bean plant Ricinus communis. Because of its high toxicity and the simplicity of producing mass quantities, ricin is considered a biological terrorism agent. We have characterized ricin extensively with a view to develop Reference Materials that could be used to test and calibrate detection devices. The characterization of ricin includes: 1) purity test of a commercial batch of ricin using electrophoresis in polyacrylamide gels, 2) biological activity assay by measuring its ability to inhibit protein synthesis, 3) quantitation of protein concentration by amino acid analysis, 4) detection of ricin by an immunoassay using a flow cytometer, and 5) detection of ricin genomic DNA by polymerase chain reaction using nine different primer sets. By implementing these five methods of characterization, we are in a position to develop a reference material for ricin.     

Potential protein degradation balance and total metabolizable protein supply to dairy cows from heat‐treated faba beans

The effects of pressure toasting (100, 118 and 136 °C for 3, 7, 15 and 30 min) on potential protein nutritional value of faba beans were evaluated with the NRC 2001 dairy model, by determining undegraded (RUP) and degraded rumen protein (RDP), undegraded (RUST) and degraded rumen starch (RDST), truly absorbed undegraded protein (ARUP), microbial protein (MCP_RDP) synthesized in the rumen from rumen‐available protein, truly absorbed rumen synthesized microbial protein (AMCP), truly absorbed rumen endogenous protein (AECP), total metabolizable protein (MP) in the small intestine, and the protein degradation balance (PDB). The treatments increased RUP, RUST, ARUP and MP (p < 0.001), and decreased RDP, RDST, MCP_RDP and PDB (p < 0.001), the effects increasing with increasing temperature and time. The treatments increased (p < 0.001) ARUP without affecting AECP and AMCP, so that the net absorbable total MP in the small intestine was increased. The PDB was reduced (p < 0.001) but never became negative. These results indicated that potential microbial protein synthesis would not be impaired due to sufficient nitrogen in the rumen, but the high positive PDB values with most treatments, except 136 °C for 15 min (PDB 2.0 g kg^?1 DM) indicated that there were large potential losses of nitrogen in the rumen, particularly for the control with a value of 88.9 g kg^?1 dry matter. It is concluded that predicted potential protein degradation balance and total metabolizable protein supply from faba beans were improved by the treatments. Copyright © 2005 Society of Chemical Industry     

霉变粉皮的微生物区系分析及防霉措施

从霉变粉皮的微生物区系分析阐述了防霉措施，抑制芽孢杆菌的最经济方法是控制粉皮的含水量，其次是添加防腐剂。     

Alternatives for nitrogen nutrition of crops in tropical agriculture

The development of sustainable agricultural systems for the tropics requires among other technologies, alternatives for nitrogen fertilizers which are often limited in availability for financial reasons and also represent a major source of groundwater and air pollution. There are many new alternatives for the development of agricultural systems which make use of biological processes in soil. Biological nitrogen fixation (BNF), that is, the biological conversion of atmospheric dinitrogen into mineral N, is the most important alternative among them. Examples are given of the impact of various technologies used in Brazil. Soybean, introduced into the country 30 years ago, is now the second most important export crop, reaching 24 million tons annually with no N fertilizer application. Consequently, Brazil today is the country in the world which uses the lowest amounts of nitrogen fertilizers in relation to phosphate. Alternatives for crop rotations and pastures are also discussed. Possibilities of expanding BNF to cereals and other non-legume crops are gaining new credibility due to the identification of endophytic associations with diazotropic bacteria. The definite proof of substantial BNF in sugar cane with N balance and¹⁵N methods in certain genotypes selected under low N fertilizer applications opens up new alternatives for sustainable agriculture and will be the key to viable bio-fuel programmes.     

Hydrochloric acid extractable minerals and phytate and polyphenols contents of sprouted faba and white bean cultivars

Two faba bean (Hudieba-72 and Bsabir) and three white bean (Serge, Giza and RO21) cultivars were sprouted for 6 days. The sprouted grains were dried and milled. Phytic acid and polyphenols contents and hydrochloric acid (HCl) extractability of minerals from the malt flours were determined at intervals of 2 days during sprouting. Phytic acid and polyphenols contents decreased significantly (P ? 0.01) with increase in sprouting time with concomitant increase in HCl extractable major and trace minerals. The contents of both major and trace minerals were slightly increased with sprouting time. When faba bean seeds were sprouted for 6 days, Bsabir had higher extractable Ca, while Hudieba-72 had higher P, whereas Fe and Mn recorded high level in Hudieba-72. When white bean seeds were sprouted for 6 days, RO21 cultivar had higher extractable Ca, while Giza-3 cultivar had higher P, whereas Fe and Mn recorded high levels in Serge and RO21 cultivars, respectively. There was a good correlation between phytate and polyphenols reduction and increase in extractable minerals with increase in sprouting time for all cultivars.     

Perspectives on allelopathy in mexican traditional agroecosystems: A case study in tlaxcala

Agroecosystems in Tlaxcala, Mexico, are surrounded by trees and water channels and have a great variety of cultivated and noncultivated plants. The main results of a study carried out on a traditional agroecosystem in Santa Inés, Tlaxcala are presented. Some ecological aspects of polycultures, plant covers (dry leaves ofAlnus firmifolia, Berula erecta, andJuncus sp.), and the allelopathic potential of crops and noncultivated plants (fresh and dry material) were analyzed. The main plants (trees, shrubs, and herbs) present in the agroecosystem were identified. The total number of weeds in plots where plant covers were added was reduced. The number of nodules ofRhizobium phaseoli and the production of bean and squash increased with plant covers. Corn, beans, and squash showed a clear allelopathic effect, as well asChenopodium murale, Tradescantia crassifolia, Melilotus indicus, andAmaranthus hybridus, among other weeds. The contribution of allelopathy in studies of traditional agroecosystems is of great importance for the management of species in space and time. Allelopathy can be the basis of biological control of pests and weeds and of the discovery of new useful substances.     

激光微束显微切割植物染色体的研究

激光微束是六十年代激光技术问世后在生物学和医学领域中出现的一项新技术。该技术利用激光方向性好、光色单一和亮度高等独一无二的特点,把激光束通过光路系统引入显微镜并聚焦成很小的光点对细胞或细胞器进行精细的细胞或亚细胞水平的显微外科术。染色体是细胞核里一种极重要的结构。每一种真核生物都有一定数目的染色体;每条染色体上都有排列次序一定的基因。任何染色体数目的变化和染色体上基因排列次序的变化,都会引起生物遗传性的变异。激光微束遗传操作真核生物染色体是激光生物学中重要和活跃的研究课题。Berns等以两栖类和哺乳动物细胞为材料进行了激光显微照射染色体及其子细胞遗传分析的大量研究。梁宏等用氩离子激光显微切割长鼻(鼠菐)培养细胞有丝分裂染色体或使受照染色体区域DNA失活都取得了成功。Monajembashi和Cremer建立了用激光微束显微切割人淋巴细胞染色体的技术。本文报道用激光微束切割高等植物染色体的实验结果,其目的是建立起对农作物染色体进行激光遗传操作的有效技术方法。     

快速法酿造豆酱

选择出快速法酿造豆酱的加工工艺条件 ,把浸豆时间提高到 2 4h ,采用高温发酵、液化糖化技术 ,并在发酵后期加入乳酸菌与酵母发酵液 ,以增加其风味物质的形成。与传统工艺相比 ,不但缩短了加工周期 ,而且豆酱中氨基酸态氮含量、还原糖含量也均比传统发酵产品提高。与现行速酿工艺相比弥补了其风味不足的缺陷。     

Textural properties of legume protein isolate and polysaccharide gels

The influence of legume proteins from lupin, pea and fababean on the formation of gels prepared by heat treatment in the absence or presence of xanthan gum, locust bean gum and NaCl was investigated. The resulting fracture and texture properties of gels not only are associated with the heating process used to form the gel but also depend on the conformational aspects of xanthan–locust bean gum in admixture with legume proteins, which after 10 days of aging reinforce the system. The fracture and textural properties are explained in terms of the effect of the protein–polysaccharide molecular structure and physicochemical conditions applied in the gel system during the gel preparation and measurements. Copyright © 2006 Society of Chemical Industry