Effects of Oxygen Absorber and Temperature on ω3 Polyunsaturated Fatty Acids of Sardine Oil during Storage

To prevent loss of w3 polyunsaturated fatty acids over long-term preservation, the effects of temperature and oxygen absorber on the fatty acids of sardine oil stored in air-tight film were studied. The fatty acids of sardine oil and lipids in the diet of experimental animals rapidly decreased over 1 month at 22°C. The amounts in the diet decreased slowly at 2°C; however, no alterations in the oil samples were observed for 6 months. Also, the amounts did not change at -30°C. Significant changes in samples treated with oxygen absorber were not observed under all temperatures during 6 months storage (P > 0.05). These results indicate that treatment with an oxygen absorber and/or freezing can prevent ω3 polyunsaturated fatty acids of fish oil from decreasing during storage.     

Bi-Cu film deposition in aqueous solutions

The relatively uniform bismuth-copper film was electrodeposited between −15 and −20 mV in the sulfate electrolyte containing 4 mmol/L bismuth ion and 2 mmol/L copper ion. Only copper was electrodeposited at −5 mV. The dendritic bismuth-copper film was electrodeposited under −20 mV. The cathodic current became constant between −20 and −400 mV. Therefore, bismuth-copper electrodeposition changes from charge transfer controlling to diffusion controlling at −20 mV. On the other hand, the uniform bismuth-copper film was electrodeposited between −5 and −35 mV in the methanesulfonate electrolyte containing 4 mmol/L bismuth ion and 2 mmol/L copper ion. The dendritic bismuth-copper film was electrodeposited under −35 mV. The potential region for good electrodepositon in methanesulfonate electrolyte is wider than that in sulfate electrolyte. Therefore, it is easy to control electrodeposition conditions by using methanesulfonate electrolyte.     

A New Aroma-Bearing Substance from Shiitake, an Edible Mushroom

SUMMARY— Investigations on the physico-chemical properties and a sensory evaluation as a component of Shiitake flavor were carried out with lenthionine, a substance which was isolated from dried Shiitake mushroom. Lenthionine is practically insoluble in water but soluble in non-polar solvents. Its stability in an aqueous solution changes greatly with the pH of the solution.
Lenthionine was identified as a significant component in the aroma of Shiitake mushroom and its detectable threshold level is at a concentration between 0.27 and 0.53 porn in water. This new aroma-bearing substance will be used as a flavor additive in various foods.     

Parameter identification of distributed parameter systems in the presence of measurement noise

A new approach to recursive parameter identification of second-order distributed parameter systems in the presence of measurement noise under unknown initial and boundary conditions is proposed. A two-dimensional low-pass filter is introduced to pre-filter the observed data corrupted by measurement noise. The low-pass filter is designed in the continuous time-space domain and discretized by bilinear transformation. Thus a discrete estimation model of the system under study is easily constructed with filtered input-output data for recursive identification algorithms. The recursive least squares method is still efficient in the presence of low measurement noise if the filter parameters are designed so that the noise effects are reduced sufficiently. Using filtered input data as instrumental variables, a recursive instrumental variable method is also presented to obtain consistent estimates when the digital low-pass filters are not designed successfully or when the output data is corrupted by high measurement noise. Illustrative examples are given to demonstrate the applicability of the proposed methods.     

Reversible Molecular Rearrangement of Slightly Acid-treated Starches

The reersible association and dissociation of starch chain populations obtained from acid-treated starches (ATSs) was investigated. Potato starch, both nonglutinous and glutinous rice starches and sago starch were suspended in 15% sulfuric acid until 1% hydroysis occured. These ATSs had relative molecular weight ranges of 25,00–29,000 daltons. In water, about half the molecules were reconstituted into large aggregates of a few million daltons. This change in molecular size depended on presence of potassium chloride. It was not observed in debranched samples. The aggregates showed a clear endothermic peak on a DSC curve. Thus, the reversibly rearranging starch chain populations were not linear, but were branched and had some type of ordered structure.     

快速加热和冷却法制备的极细多芯Nb3Al线材的超导特性

介绍了一种快速加热快速冷却制备接近化学计量的Ｎｂ３Ａｌ极细多芯线材的方法。用四控地测定试样的临界温度为１７Ｋ,用Ｓｐｌｉｔ ｐａｉｒ型磁体测试了试样随温度和磁场变化的临界电流。归一化后的单位体积钉轧力与所加磁场符合Ｋｒａｍｅｒ方程,晶界为可能的磁力线钉扎源。由临界电流得到的上临界磁场与温度呈线性关系,外摊得到临界温度的计算值与实测值基本一致。通过临界电流与温度和磁场的关系得到了Ｉｃ－Ｔ－Ｂ三维临界     

酶在洗涤剂中的应用现状及展望

论述了洗涤剂用酶的发展史和常用4种酶(特别是纤维素酶)的特性、去污机理、功能和应用现状。指出了近年来洗涤剂用酶的动向：开发具有耐氧化性、低温下活性高、对洗涤剂和洗涤环境适应性好的变异蛋白酶已商品化;一些反应性更好,对油污吸附性更强的改良脂肪酶已出现;一类在高碱性、低温介质中能充分保持活性的淀粉酶正在积极开发中;一类纤维素复合体可以分解棉纤维表面的毛球正在开发中;一种对纤维损伤较小的护色的酶制剂进入实用阶段;一种可有效防止再污染,能与棉质衣料作用产生其他不同效果的独特酶制剂正在引起同行注意。今后,随着洗涤剂种类和用途的变化,用多种不同的酶制剂复配的复合型加酶洗涤剂品种将源源不断地上市,洗涤剂中酶制剂的用量不断增加、化学物质总量尽量降低将成为加酶洗涤剂发展的趋势。