Functional Properties of a Peptide of 23 Residues Purified from the Peptic Hydrolyzate of asl-CASEIN: Changes in the Emulsifying Activity During Purification of the Peptide

The pH 4.6-soluble fraction of the peptic hydrolyzate of as 1-casein contained the 23 N-terminal residues, αsl-CN(fl-23), as a major pep-tide. Reversed-phase HPLC indicated that small amounts of other peptides such as αsl-CN(f154-199) were also contained in this fraction. By removing of these peptides, the emulsifying activity (EA) of the αsl-CN(fl-23) fraction was markedly decreased. However, when the removed peptide fraction was added to the purified αsl-CN(fl-23), the EA was increased. Some synergistic effect in the emulsification seemed to exist between αsl-CN(fl-23) and the other peptides. Although the purified αsl-CN(fl-23) had low EA values at neutral pH levels, it showed high emulsifying and surface activities in the acidic pH region.     

A New Protein Band Appearing in the Electrophoretic Pattern of Egg White Heated at Below 60°C

When egg white was heated to between 50° and 60°C, a new protein band appeared in its polyacrylamide gel electrophoretic pattern. The formation of the protein band in stored egg white was almost the same as that of fresh egg white. This protein band was shown to be induced by the interaction between macroglobulin and lysozyme during the egg white heating. The optimum temperature for its formation was between 54°C and 57°C. This band formation may be used as an indicator for heat treatment of egg white.     

A Conceptual Design Study for the Error Field Correction Coil Power Supply in JT-60SA

This paper describes a conceptual design study for the circuit configuration of the Error Field Correction Coil (EFCC) power supply (PS) to maximize the expected performance with reasonable cost in JT-60SA.The EFCC consists of eighteen sector coils installed inside the vacuum vessel,six in the toroidal direction and three in the poloidal direction,each one rated for 30kA-turn.As a result,star point connection is proposed for each group of six EFCC coils installed cyclically in the toroidal direction for decoupling with poloidal field coils.In addition,a six phase inverter which is capable of controlling each phase current was chosen as PS topology to ensure higher flexibility of operation with reasonable cost.     

Properties of Space Charge Distributions and Conduction Current in XLPE and LDPE under DC High Electric Field

Space charge behavior and conduction current in polyethylene under dc stress were investigated. One of the reasons for the different breakdown property in cross‐linked polyethylene (XLPE) from that in low‐density polyethylene (LDPE) may be based on the existence of cross‐linking by‐products in XLPE. Furthermore, a thermal history in cross‐linking process for XLPE may also cause of the difference. It is generally accepted that the existence of the cross‐linking by‐products increase the conduction current in XLPE under dc stress. It is also said that an anneal treatment in air atmosphere may affect to the electrical properties under dc stress. Therefore, we investigated the effect of the cross‐linking by‐products and the anneal treatment on space charge behavior and conduction current in polyethylene under dc stress. In our research, it is thought that the increasing dissipation power in XLPE is the cause of the breakdown in it under dc stress. Therefore, to calculate the dissipation power in the bulk of test sample, we measured the space charge distribution and the external circuit current simultaneously. Based on the results, we discussed the reason of the difference of the space charge properties in XLPE and LDPE focusing on the cross‐linking by‐products and the oxidation of the test samples.     

Identification of Low Molecular Weight Peptides in Gouda-type Cheese and Evidence for the Formation of These Peptides from 23 N-terminal Residues of αsl-casein by Proteinases of Streptococcus cremoris H61

Water-soluble extracts from Gouda-type cheese in a 0.05M sodium citrate buffer at pH 4.0 were fractionated by high-pressure liquid chromatography (HPLC) before and after ripening for 1, 2, and 3 months. Three major peptides were isolated from each sample of extract, but size of the peaks increased with ripening period. The amino acid compositions of these peptides were similar to fragments of αsl-casein, i.e., αsl-CN(fl-9), αsl-CN(fl-13) and αsl-CN(fl-14). αsl-CN(fl-23) was hydrolyzed by cellular proteases of Streptococcus cremoris H61; seven main peptides including αsl-CN(fl-9), αsl-CN(fl-13) and αsl-CN(fl-14) were isolated and characterized by HPLC. This suggests that hydrolysis of αsl-CN(fl-23) by lactic acid bacterial proteinase is one of the main pathways of αsl-casein degradation during Gouda-type cheese ripening.     

Allergic Skin Reactivity and Chemical Properties of Allergens in Two Grades of Lactose

Skin tests of the nondialyzable fraction of lactose were performed on patients with a clinical diagnosis of cow's milk allergy. The yields of brownish-colored residue, allergens (ALG), were 0.006% from reagent grade lactose (ALG 1) and 0.011% from lactose used in a commercial infant food formula (ALG 2). The ALG was separated into four fractions by chromatography on Sephadex G-75. The highest incidences of positive skin reaction among the four ALG 1 and ALG 2 fractions were 8/9 and 8/12 respectively. The ALG fractions were identified as a sugar protein complex and the protein moiety of ALG contained high amounts of glutamic acid (or glutamine), threonin, asparagic acid (or asparagine) and proline.     

Heat-Induced Gelation of Hen's Egg Yolk Low Density Lipoprotein (LDL) Dispersion

The heat-induced gelation of hen's egg yolk low density lipoprotein (LDL) dispersion (3.5%) was studied in comparison with ovalbumin (OV) and bovine serum albumin (BSA). Stable gels of both OV and BSA were formed only at the narrow pH regions, but LDL gels obtained at every pH between 4 and 9 were stable. The presence of large amounts of salts decreased the rigidity of both OV and BSA gels, especially on the acid side of the isoelectric point of the proteins, but did not affect that of LDL gels at every pH tested. The results indicated that the heat-induced LDL gels were more stable than those of OV and BSA under various environmental conditions.