Reverse osmotic properties of the membranes prepared from the polycondensate of 2,5-pyridinedicarboxylic acid chloride and malonyl dihydrazide

Summary The membrane performance of the polycondensates derived from 2,5-pyridinedicarboxylic acid chloride and malonyl dihydrazide was studied in reverse osmosis. It depended on drying time, and the kind and amount of a cross-linking agent and an inorganic additive. The membrane strength generally exceeded that of a cellulose acetate membrane. The rejection difference between transition and alkali metal salts was discussed in terms of complexation and the molecular size of the additive. A potential application was suggested for the separation between the two metals through the membrane of a large rejection difference.     

北京周边地区低盐固态制曲过程中酶系活力的变化

通过对北京周边地区4个低盐固态酱油厂家制曲过程进行跟踪监控,测定分析其制曲过程中中性、酸性和碱性蛋白酶、淀粉酶、纤维素酶、谷氨酰胺酶和亮氨酸氨肽酶活力的变化.结果表明,即使是同种工艺不同厂家之间的各个酶活力存在显著性差异,同时现有工艺不能产生丰富且较高酶活的酶系.     

Kinetic aspects of dyeing processes

The dyeing of textiles was classified into two main categories: reactive and adsorptive dyeing. A mathematical model for each case was developed on the basis of a pore model concept. The validity of the proposed models was confirmed by comparison with existing experimental data on dyeing of reactive dyes in cellulose and acid dyes in nylon. It was further desired that the proposed models be checked by experimental results in high fixation regimes. The overdyeing phenomenon may be simulated by intrafiber diffusion with simultaneous multimodal adsorption.     

酸性电解水用于葡萄杀菌保鲜的试验研究

用不同指标的酸性电解水对葡萄进行处理,对处理后果实的微生物总数、霉菌总数以及腐烂率、脱粒率进行了对比研究,结果显示:经不同指标酸性电解水浸泡处理后,果实表面微生物数量均显著降低,果实的总损失率也明显降低;对比发现,强酸性电解水的防腐保鲜效果最优;葡萄果实采后用酸性电解水处理可以有效的提高其商品价值及食用安全性。     

大豆蛋白热变性程度对豆腐品质的影响

本文主要研究了豆腐加工过程中 ,生豆浆在不同加热处理条件下对豆腐强度和失水率的影响 ,得出豆浆在 95℃ ,保温 10min的加热条件下 ,豆腐的强度最大 ,失水率最低。分析了不同加热条件下 ,豆浆中蛋白的表面疏水性和巯基含量 ,得出豆浆蛋白表面疏水性的增加和巯基含量的增多 ,可以使豆腐强度增大 ,失水率降低。本文为豆腐的工业化生产提供了理论依据和有益的参数。     

Screening of α-Amylase Suitable for Evaluating the Degree of Starch Retrogradation

To estimate the degrees of starch retrogradation in the complex foods, an enzymatic method using α-amylase from Bacillus subtilis was proposed in the previous report (Tsuge, H. et al.: Starch/Stärke 42 (1990), 213–216). However, actual digestibility of the enzyme for the native starch granules was not checked at that time. A comparative study to see the digestibility of native starch granules was carried out using four different α-amylase preparations and digestion of retrograded wheat starch was tested by two α-amylase preparations. Pancreas α-amylase preparation digested some native starch granules to a great extent, while Aspergillus oryzae enzyme did not digest native starch granules virtually. In conclusion, α-amylase preparation from A. oryzae was an ideal enzyme as the tool to distinguish between raw and gelatinized starches. It was justified for the use of A. oryzae enzyme as well as B. subtilis α-amylase to evaluate the retrograded starch contents in the complex foods.