Binding of Taurocholate by Pectin in the Presence of Calcium Ions

Binding of taurocholate by pectin was examined in vitro, using low-methoxyl pectin and calcium lactate. Water in calcium pectate gel was partially separated from the gel by filtration through a glass-filter. Taurocholate bound by pectin was calculated after measurement of taurocholate in the filtrate by the UV absorption method. The amount of taurocholate bound by pectin increased linearly with increase in pectin concentration but independent of time. One gram pectin bound a maximum of 6.0 μmole of taurocholate.     

Decomposition of Two Aluminum Sulfates and Characterization of the Resultant Aluminas

Two special types of anhydrous aluminum sulfate with extreme grain shapes were prepared; one, obtained by precipitation from concentrated sulfuric acid solution, is rhombohedral near cubic single-crystal grains and the other, from acetic acid solution, consists of very thin flaky particles. The morphology of sulfate and calcined alumina, the sulfate decomposition, the η-α alumina transformation, and the crystallite growth of α alumina were studied and compared with those processes for reagent-grade sulfate. The morphology of anhydrous sulfate was shown to greatly affect the heat-treatment characteristics of alumina and the sulfate decomposition behavior.     

Formation of N-Substituted Pyrrole-2-Aldehydes in the Browning Reaction Between D-Xylose and Amino Compounds

SUMMARY– The formation of N -substituted pyrrole-2-aldehydes in the browning reaction between D-xylose and selected amino acids was investigated.
In order to facilitate the separation of the reaction products, the carbonyl compounds formed in the browning solution were converted into 2,4-dinitrophenylhydrazones (2,4-DNPs) and then esterified with diazomethane. Isolation of the esterified 2,4-DNP was accomplished by column chromatography with alumina. Chemical structures of the isolated 2,4-DNPs were confirmed by elementary analyses, ultraviolet and visible absorption spectra, and nuclear magnetic resonance spectra.
The following N -substituted pyrrole-2-aldehydes were isolated as methyl ester of 2,4-DNP, respectively: (2-formylpyrrol-I-ybacetic acid from the reaction mixture of D-xylose and glycine, 3-(2-formylpyrrol-1-y1)propionic acid from β-alanine, and 2-(2-formylpyrrol-1-y1)-4-methyl-valeric acid from L-leucine.
The extent of pyrrolealdehyde formation from D-xylose and selected alkylamine or amino acid was in the following order which corresponded to the extent of melanoidin formation: n-butylamine > methylamine, β-alanine > glycine > DL-alanine. N-substituted pyrrole-2-aldehyde was rather stable and was not considered to be an important intermediate of melanoidins. However, some correlationships between the formation of pyrrolealdehyde and that of melanoidins were demonstrated and discussed.     

A successive projection method for binary pattern recognition with multilayer feedforward neural networks

Error back-propagation (BP) is one of the most popular ideas used in learning algorithms for multilayer neural networks. In BP algorithms, there are two types of learning schemes, online learning and batch learning. The online BP has been applied to various problems in practice, because of its simplicity of implementation. However, efficient implementation of the online BP usually requires an ad hoc rule for determining the learning rate of the algorithm. In this paper, we propose a new learning algorithm called SPM, which is derived from the successive projection method for solving a system of nonlinear inequalities. Although SPM can be regarded as a modification of online BP, the former algorithm determines the learning rate (step-size) adoptively based on the output for each input pattern. SPM may also be considered a modification of the globally guided back-propagation (GGBP) proposed by Tang and Koehler. Although no theoretical proof of the convergence for SPM is given, some simulation results on pattern classification problems indicate that SPM is more effective and robust than the standard online BP and GGBP     

APPLYING PROTEOLYTIC ENZYMES ON SOYBEAN. 6. Deodorization Effect of Aspergillopeptidase A and Debittering Effect of Aspergillus Acid Carboxypeptidase

SUMMARY— A proteolyzate obtained by treating an isolated soybean protein preparation with Molsin, a crude preparation of aspergillopeptidase A (APase A), was less bitter and contained larger amounts of free amino acids, especially hydrophobic amino acids. A proteolyzate obtained by treating this protein preparation with crystallized APase A was much more bitter and contained smailer amounts of free amino acids, mainly consisting of hydrophilic amino acids. The latter was richer in peptides than the former, bearing hydrophobic amino acid residues near the C-termini. Difference in N-terminal amino acid composition apparently has not been found between the 2 proteolyzates. These results indicate that Molsin per se contains a certain carboxypeptidase which decomposes the C-terminal structures and, consequently, lessens the bitterness (debittering effect). This carboxypeptidase was found to be identical with aspergillus acid carboxypeptidase (AACPase). Abase A, as well as MO/sin, was effective in removing odor ants, i.e., n-hexanal, n-hexanol and n-heptanol, from the isolated soybean protein preparation Ideodorization effect). AACPase seemed to have no deodorization effect. A method was suggested to prepare a deodorized and debittered proteolyzate by a combination use of APase A and AACPase.     

Physical Properties of Soy Bean and Broad Bean 11S Globulin Gels Formed by Transglutaminase Reaction

Physical properties of transglutaminase-induced glycinin and legumin gels were compared with thermally induced gels. Results of deformation tests showed that transglutaminase-induced gels were more rigid and elastic than thermally induced gels. From creep compliance tests, all elastic moduli and viscosities except Newtonian viscosity were higher for transglutaminase-induced gels. Electron micrographs revealed that network structures of transglutaminase-induced gels were composed of larger unit particles forming more developed strands and clusters. More rigid and elastic gels were formed from glycinin as compared to legumin by both gelling methods.     

Crosslinking Between Different Food Proteins by Transglutaminase

Guinea pig liver transglutaminase has been found to catalyze the formation of inter- and intramolecular ε-(γ-glutamyl)lysyl crosslinks in proteins. In this paper we study the formation of polymers between different proteins by reacting them with transglutaminase. Analysis of reaction products between acetylated α_s1 -casein and several proteins (α_s1 -, k-casein, β-lactoglobulin, soybean 11S and 7S globulin) by sodium dodecyl sulfate polyacrylamide gel electrophoresis and high-performance liquid chromatography indicated that the different proteins were polymerized through the formation of intermolecular crosslinks. This reaction may represent a procedure to improve the properties of food proteins.     

Textural Degradation of Cooked Fish Meat Gel (Kamaboko) by the Addition of an Edible Mushroom, Judas' Ear (Auricularia auriculajudae (Fr.) Quel)

Commercial makers of kamaboko, a traditional Japanese preparation of gelled cooked fish meat, have observed that when slivers of the edible Judas' ear mushroom (Auricularia auricula-judue (Fr.) Quel) are incorporated into the gel without being cooked first, the gel tends to have an unsatisfactory texture. Experiments with casein as substrate have already shown that this mushroom has a proteinase. We showed that the proteinase acted on fish myofibrillar proteins, including myosin, actin, and tropomyosin. In kamaboko containing Judas' ear mushroom uncooked, fish proteins were hydrolyzed and gel strength decreased. The results showed that the decrease in gel strength was caused by the hydrolysis of fish proteins by the proteinase.     

ε-(γ-Glutamyl)lysine Crosslink Distribution in Foods as Determined by Improved Method

Quantitative analysis of ε-(γ-glutamyl)lysine crosslink in 127 foods was achieved with a, preliminary separation by reverse phase-HPLC before o-phthalaldehyde derivatization to remove interfering peaks. ε-(γ-Glutamyl)lysine was detected in 96 foods and its contents ranged from 0.2 to 135 μmol/lOOg protein. High levels were found in fish paste products, processed fish, shellfish, meats and soybeans, and raw poultry organs. For fish and meats, the level of ε-(γ-glutamyl)lysine in processed foods and fish paste was relatively higher than that in raw materials. The improved procedure could be applied for screening materials with transglutaminase activities.     

EFFECTS OF DIETARY PLANT CEREBROSIDE ON GENE EXPRESSION IN THE LARGE INTESTINE OF 1,2-DIMETHYLHYDRAZINE (DMH)-TREATED MICE DETERMINED BY DNA MICROARRAY ANALYSIS

The effects of dietary plant cerebroside on colon gene expression by DNA microarray analysis in 1,2-dimethylhydrazine (DMH)-treated mice were investigated. After 9 weeks of feeding with DMH, decreases and increases in the levels of expression of 110 and 145 genes were detected, respectively. Especially, the expression of Soggy-1, which suppresses the Wnt signaling pathway, was increased, while that of Ras-associated protein, which induces the mitogen-activated protein (MAP)-kinase pathway and is responsible for the development of aberrant crypt foci (ACF), was decreased. The results of the present study indicated that dietary cerebroside in DMH-treated mice regulates the Wnt signaling and MAP-kinase pathways, and prevents the development of ACF in the large intestine.

PRACTICAL APPLICATIONS

Dietary plant cerebroside increased expression of Soggy-1 mRNA, which suppresses the Wnt signaling pathway, and decreased expression ofRas-associated protein, which induces the MAP-kinase pathway in 1,2-dimethylhydrazine (DMH)-treated mice. The results of the present study indicated that dietary cerebroside in DMH-treated mice regulates the Wnt signaling and MAP-kinase pathways, and prevents the development of aberrant crypt foci in the large intestine, thus being of potential use for nutraceutical applications.