Physical Treatment Reduces Trypsin Inhibitor Activity and Modifies Chemical Composition of Marama Bean (Tylosema esculentum)

The utility of the marama bean (MB) as an alternative protein source to soybean (SB) can be limited by the high concentration of trypsin inhibitors (TI). The physical treatment of MB has the potential to ameliorate the antinutritional activities of TI and modify other chemical components. Thus, this study investigated the effects of physical treatments on the chemical components and trypsin inhibitor activity (TIA) of raw MB and SB. The bean substrates were subjected to each of the following treatment methods: (1) room temperature (20–22 °C) soaking for 24 h; (2) electric stove cooking at 100 °C for 10, 20, and 30 min; (3) steam autoclaving at a temperature of 110 °C and pressure of 7 pounds per square inch (psi), as well as a temperature of 121 °C and 7 psi for 5, 15, and 30 min; (4) pre-soaked autoclaving at 110 °C (7 psi) and 121 °C (17 psi) for 5, 15, and 30 min. Treated MB and SB had greater (p < 0.05) crude protein content than untreated samples. All the treatments (except 24 h soaking of MB) reduced (p < 0.05) the TIA and ash content. Marama and SB are similar in protein content, but their amino acids profile and TIA are quite different. Soaking for 24 h was less effective in reducing TIA in MB and SB, compared to the thermal methods, and it was detrimental to the ash and amino acids profile of the two beans. Soaking prior to autoclaving yielded beans with the lowest TI concentrations. In conclusion, thermal methods reduced the TI contents and modified the level of proximate components and amino acids profile of the beans.     

应用高浓度介质进行预处理试验时值得注意的问题

测定了多种高浓度介质在高压灭菌前后的渗透值,pH值变化状况及其时程。分析了不同介质预处理后多核糖体状况、可溶性蛋白凝胶电泳谱和花粉雄核发育状况的变化。结果表明:多核糖体状况的变化与介质在高压灭菌后的pH差异相关;可溶性蛋白电泳谱的变化与介质渗透值关系较密切,且可能与离子胁迫相关;而雄核发育则与pH值、高渗均有关而以pH值关系更为密切。从试验结果看,可认为:1.高渗介质预处理的起始影响,按照介质种类,可能包括渗进胁迫、pH胁迫、和离子胁迫。2.不同影响的作用位置可能各不相同,时程也可能有异。3.在高渗介质预处理试验设计中应注意介质种类和影响特点的选择,注意对照的设置;即使采用过滤灭菌也应事先做好基础测试工作。     

High Performance Liquid Chromatographic Determination of Nordihydroguaiaretic Acid

Abstract

A high performance liquid chromatography (HPLC) method was developed for the detection and quantitation of nordihydroguaiaretic acid (NDGA). Very low concentrations of NDGA in various extracts are detectable, thus making the method more sensitive than other previously reported analytical techniques. NDGA was extracted from leaves of Larrea divaricata as well as from rodent food containing NDGA. Since rats are fed NDGA in studies that examine the development of renal cystic disease, we modified extraction procedures to permit isolation of NDGA from tissue and serum samples.     

Effect of autoclaving temperature on calcium silicate-based building products containing clay-brick waste

The utilisation of fired clay-brick waste is of interest in the manufacture of building products due to both socio-economic and technological reasons. Autoclaving is an established process for manufacturing calcium silicate-based building products that affords rapid strength development. Clay-brick waste represents a source of alternative silica, which is more reactive than conventionally used silica and also contains alumina. This paper presents data on the effect of lowering the autoclaving temperature from commonly practised 180 to 170°C on OPC-quartz blends containing clay-brick fines as direct replacement of quartz at 4.3, 8.6 and 12.9 mass percentages. The hydration products of autoclaved OPC-quartz blends with clay-brick fines were characterised using simultaneous DTA-TG in combination with other methods.     

Use of DTA-TG in the evaluation of autoclaved cement-based systems: Part I. Cement-brick waste blends

Fired-clay products such as bricks, tiles and pavers, are made in large volumes for use in a variety of construction applications throughout the world. A significant proportion of them ends up being a waste product either during their production process or the demolition of buildings. High pressure steam curing or autoclaving has proven extremely versatile for the manufacture of cement-based building products incorporating waste materials such as fly-ash and blast furnace slag. The nature of hydration products in an autoclaved cement based system incorporating different amounts of finely ground brick waste was investigated by means of thermal analysis and XRD, and is the subject of this paper.This revised version was published online in November 2005 with corrections to the Cover Date.     

Thermal characterisation of autoclaved cement made with alumina-silica rich industrialwaste

The hydration products of hydrothermally cured OPC-quartz blends incorporating clay-brick waste were characterised using simultaneous DTA-TG, XRD and SEM. The exotherm above 800°C on the DTA curve, due to the formation of β-wollastonite (β-CS) was related to the compressive strength. The area and/or height of the exotherm increased with compressive strength and was due primarily to the presence of calcium silicate hydrate phases including 1.1 nm tobermorite. Supporting evidence is provided by XRD and SEM.