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.     

Coordination polymers as precursors of simple and complex oxides

Coordination polymers (CPs) are assembled from metal ions and organic linker molecules. Here, we demonstrate that CPs can be used as precursors for simple and complex oxide synthesis. First, we investigated the conditions for linker solutions in which CP was obtained as precipitate only by mixing and stirring the solutions for each of the 28 metal–ion aqueous solutions. Evaluation of the crystalline phase of the samples obtained by firing the precipitates revealed that CPs could be used as precursors of simple oxides for 21 metal ions. Next, we conducted experiments to prepare precursors of 10 complex oxides with an A_nB_nO_m composition containing equimolar amounts of metal ions. Seven complex oxides were successfully synthesized. Three of them were complex oxides that could not be synthesized by the spray coprecipitation method. The present method has a comparable precursor preparation capability to the spray coprecipitation method. Because of the much shorter time for the precursor synthesis, the present method should be useful for parallel and automated experiments.