The effectiveness of electrolyzed cathode water (ECW) prepared by the electrolysis of NaCl (100 mg/L) aqueous solution was examined in inhibiting the oxidation of some reductants which are widely used in food and biochemical researches. When L-ascorbic acid dissolved in the ECW or sodium hydroxide aqueous solution was incubated for 30 min, the remaining ratio of L-ascorbic acid dissolved in ECW was 1.21-1.24 times higher than that dissolved in sodium hydroxide aqueous solution. The oxidation-reduction potential of ECW decreased with hydrogen gas generation after electrolysis, namely the reducing potency of ECW became higher. Thus the oxidation of L-ascorbic acid was considered to be depressed by such a high reducing potency. The decreased level of dissolved oxygen in ECW by the hydrogen gas generation related to its antioxidative activity. The oxidation of dithiothreitol, 2-mercaptoethanol and α-tocopherol were also depressed in the ECW. It was confirmed that the reducing potency and low dissolved oxygen concentration were responsible for the antioxidative activities of ECW toward dithiothreitol and 2-mercaptoethanol. However, unlike the cases of these hydrophilic reductants, the depressing effect of ECW on the oxidation toward α-tocopherol, a lipophilic reluctant, could not be explained only by the reducing potency and low dissolved oxygen, probably because it existed as an emulsion in the presence of the surfactant, sodium dodecyl sulfate.
The apparent distribution coefficients Kapp of glucose, galactose, mannose and fructose onto the resins with different divinylbenzene contents in Li+, Na+, K+, Ca2+ and Sr2+ forms were determined in a dilute system by the moment analysis of the elution profile. The binding constant B of a solute to a counter-ion, which was free from the effect of swelling pressure of the resin, was estimated from the Kapp values based on our previous model where glucose was assumed to form no complex with any counter-ion. The B value for each solute, except for glucose, could be correlated with the dynamic hydration number of the counter-ion.
The mixing (axial dispersion) performance in expanded bed chromatography (EBC) was examined by the pulse response (residence time distribution) curve measurements. The HETP (height equivalent to a theoretical plate or plate height) values were calculated from the peak variance and the peak retention time. The HETP values for EBC did not change appreciably with the expansion degree (1.5-3.5), the column diameter (1.6 and 2.6cm), or the settled bed height (ca. 4-10cm), and ranged between 0.8 and 1.6cm. The breakthrough curves of lysozyme for very small EBC (1.6cm diameter and 3cm settled bed height) are similar to those for fixed bed chromatography (FBC) . This indicates that the adsorption performance of EBC is similar to that of FBC and the scale down of EBC is possible. As a food separation model sysytem lysozyme recovery from egg white by EBC was carried out. The recovery ratio and the purification factor obtained were similar to those with FBC although significant pressure drop increases were observed for FBC. Similarly, crude β-galactosidase was successfully purified by EBC. Several important factors affecting the separation performance of EBC for food separations were discussed.
Multilayer film elements used in hospitals for clinical diagnosis contain all chemicals that are necessary for colorimetric reaction sequence including enzymes. Because of the nature of protein, most enzymes show less stabilities than other organic or inorganic compounds. Therefore, it is very important to prevent the loss of enzyme activity in multiplayer film elements. So for, some sugars are known to stabilize enzymes and recently one of disaccharides called trehalose has been the topic in many fields such as cosmetics and food industries. Here we demonstrate that sugars like trehalose, maltose and sucrose stabilize enzymes also in multiplayer film elements. Multilayer film elements consist of transparent support, reaction layer that is made of gelatin, and blood spreading layer. Enzymes are usually immobilized in reaction layer or spreading layer. In this paper, we report the stabilization of enzymes immobilized on the surface of fiber as spreading layer by using some sugars. Those three disaccharides clearly protect enzymes from the loss of their activities during the manufacturing process and the storage of multiplayer film elements. And we also refer about the possibility of Km value as the index of the stability of enzymes in aqueous solution including many kinds of chemicals.
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