Denaturation of Bovine Serum Albumin (BSA) and Ovalbumin by High Pressure, Heat and Chemicals

Both native and denatured protein samples were examined by determining fluorescence and specific rotation, and by polyacrylamide gel electrophoresis (PAGE) and differential scanning calorimetry (DSC). Denaturation of ovalbumin by pressure was much less than by heat or by the chemical denaturants. Ovalbumin was denatured under high pressure, as confirmed by the decrease in its a-helical content to 72% and DSC endothermic enthalpy to 61%, but it showed no change in the PAGE pattern. With bovine serum albumin decrease in fluorescence was observed after denaturation by chemicals, but it did not change under high pressure.     

Functional Improvement of Alginic Acid by Conjugating with β-Lactoglobulin

Two bovine β-lactoglobulin-alginic acid (β-LG-ALG) conjugates were prepared to improve the function of ALG by using water-soluble carbodiimide and the Maillard reaction. Fluorescence studies suggested that the conformation around Trp had been changed in each conjugate and that the surface of each conjugate was covered with polysaccharide chain. Structural analyses with monoclonal antibodies indicated that the conformation around 15Val-29IIe (β -sheet) in each conjugate had changed, while the native structure was maintained around 125Thr-135Lys (α-helix). After conjugating with β -LG, ALG showed retinol-binding and high emulsifying ability. The aggregating property of ALG in acid and in the presence of Ca²⁺ was improved in each conjugate.     

氧化物弥散强化铁素体钢的电子辐照行为

本文利用超高压电子显微镜进行电子辐照实验,分析了我国试制的氧化物弥散强化（ＯＤＳ）铁素体钢的辐照行国．在６７０－７２０Ｋ下辐照时观察到了辐照空洞的形成．辐照条件为７２０Ｋ,９ｄｐａ时的辐照肿胀率小于０．１％．同时在电子衍射图样中发现了明显的衍射环,分析表明这些衍射环的出现是由于电子辐照促进了Ｙ２Ｏ３微细相形成的缘故．     

Hf对铁素体钢中辐照引起的晶间偏析的影响

1％Hf（质量分数）被注入E911钢中．利用250keV的Ni离子在300℃辐照含Hf和不含Hf的E911钢,以研究Hf的添加对铁素体／马氏体钢中由辐照引起的偏析的影响．结果表明,Hf的添加抑制了晶界上P原子的富集和Cr原子的贫化．讨论和评估了Hf对自由迁移的缺陷数量的影响,结合一个辐照引起的非平衡偏析（RIS）模型以预测Hf对P3Cr等元素的晶界偏析行为的作用．对预测结果和实验数据作了比较．     

Influence of pulsed electric field on enzymes,bacteria and volatile flavor compounds of unpasteurized sake

A pulsed electric field(PEF) was applied to unpasteurized sake at constant temperatures, at which α-amylase was not inactivated. We adjusted the input energy to be identical for the temperatures by changing the number of PEF application, because the current significantly increased with the temperature, even the amplitude of the applied voltage was identical. As a result, the α-amylase was seemed to be inactivated by PEF application, not due to thermal effect.The glucoamylase was significantly inactivated by PEF. Moreover, the acid carboxypeptidase was inactivated by PEF at 4 °C but significantly activated at 25 °C. These results show that the sensitivity of enzyme to PEF application differs depending on the types of enzyme and treatment temperature. On the other hand, the colony number of bacteria was remarkably decreased, but the amount of the volatile flavor compounds was not decreased by PEF application.     

Extracellular Polysaccharide from Encapsulated Streptococcus sajivarius subsp. thermophilus OR 901 Isolated from Commercial Yogurt

Strains of S. thermophilus grown on partially deproteinized whey produced an exocellular polysaccharide which contained L-rhamnose and D-galactose in the ratio 1:1.47. Methylation analysis showed the existence of 3 and 6-substituted D-galactose, 2-substituted L-rhamnose and nonreducing terminal D-galactose. A polysaccharide was also obtained from the cell surface after sonication. Molecular weights of both polysaccharides were estimated by gel filtration on HPLC at about 9,000,000 and 1,100,000, respectively. These polysaccharides were different from the previously reported products by S. thermophilus strains and their presence may contribute to the ropy property of yogurt.