A mixture of chicken meat and isolated soybean protein was heated after curing with salt and then the heat coagulation of protein was investigated by means of SDS polyacrylamide gel electrophoresis. (1) When the mixture was heated at 70°C, a large portion of the meat protein was coagulated and could not be detected on the electrophoretic patterns of the low concentration salt-soluble fraction. Heat coagulation of the soybean protein, however, was not so thorough as that of the meat protein and the subunits of 7S and 11S components could be detected on the electrophoretic patterns of this fraction. When the heat-temperature was raised up to 100°C, the subunits of the 7S component markedly decreased, while those of the 11S component only slightly decreased in this fraction. The heat stability of the soybean protein was improved by the salting process. Though the salt extractable proteins of the mixture also remarkably decreased by heating, the bands of tropomyosin, faster-moving meat proteins and some of the soybean protein were faintly appeared on the electrophoretic patterns of the salt-soluble fraction. The tropmyosin and faster-moving meat proteins slightly increased by the salting. (2) By means of SDS polyacrylamide gel electrophoresis of low concentration salt soluble fractions, the detection of the soybean protein contained in the mixtures of chicken meat and isolated soybean protein has also been examined. This investigation showed that this method was efficient in the qualitative determination of the soybean protein in mixtures of meat and isolated soybean protein.

View full abstract

Banana (Musa sapientum L.) fruit ripened at 20°C and 30°C produced a large quantity of volatile compounds including isoamyl acetate, however, the production was extremely suppressed in the fruit ripened at 35°C. The contents of L-leucine, α-ketoglutarate, isoamyl alcohol, acetic acid, ATP and CoA which were considered as the metabolites or co-factors of assumed isoamyl acetate biosynthetic pathway in the fruit, were determined during ripening at 20°C, 30°C and 35°C. ATP content in the fruit decreased during ripening at all temperatures, but the other compounds increased at 20°C and 30°C. At 35°C, however, these compounds decreased except α-ketoglutarate and acetic acid. The activities of the enzymes which were thought to catalize isoamyl acetate biosynthesis, that is, leucine transaminase, α-ketoisocaproate decarboxylase, alcohol dehydrogenase, acetyl CoA synthetase and acyl CoA-alcohol transacylase increased during ripening at 20°C and 30°C, but the activation was prevented at 35°C. Among the enzymes mentioned above, α-ketoisocaproate decarboxylase and acyl CoA-alcohol transacylase were not detected in mature-green stage, suggesting that the appearance of these two enzymes would play most important role in the development of isoamyl acetate biosynthetic pathway in ripening banana fruit. In addition, the activation of other enzymes and increases of substrate contents in the pathway are also supposed to contribute the production of isoamyl acetate. It may be concluded that the postulated pathway of isoamyl acetate biosynthesis develops in banana fruit during ripening, while it must be suppressed at 35°C in storage temperature.

View full abstract

Effective compounds in the fermented seasoning (Sakashio) for odor-masking of trimethylamine (TMA) were discussed. The fermented seasoning was fractionated into volatiles and non-volatiles. The non-volatile fraction was then divided into methylene chloride soluble and water soluble fractions. Furthermore, the water soluble fraction was fractionated into acid, nitrogen containing and neutral fractions. The odor-masking effect of the fractions mentioned above on TMA was examined by a combination of sensory evaluation and headspace analysis with GC. (1) The water soluble fraction was effective for masking TMA ordor. The acid and the nitrogen containing fractions were effective for the TMA odor-masking. (2) A strong effect for masking of TMA odor in the water soluble fraction was depended on the formation of salts that comprised of organic acids and amino acids. An ionic bond in the salt formation was so strong that the salts were easily isolated from the model mixture without any change of the compound. (3) In a model system with on amino acids solution, not only acidic amino acids but neutral and basic amino acids could make the ordor-masking effectively. A certain correlation (r=0.87, α=0.01) between the odor-masking effect and the isoelectric point (pI) of amino acid has been found. (4) The masking effect of the fermented seasoning for TMA ordor depends on hydrophilic compounds such as organic acids and amino acids, owing to a buffer action of the acids. Amino acids act weakly as a buffer but are effective in wide ranges of pH.

View full abstract

In the previous paper, the enzymatic properties of xylanase produced by koji molds cultured on steamed wheat bran was reported. In this paper, the enzymatic properties of arabinanase, galactanase, and mannanase produced by the koji molds are investigated. The results obtained were as follows: (1) The best conditions to determine the enzymatic activity of koji molds were to incubate the mixture of the enzyme and substrates including arabinan from beet pulp, arabinogalactan from soybean meal, or galactomannan from soybean hull in a buffer solution of pH 4.5 for 60 minutes at 40°C. (2) Arabinanase and galactanase were stable at pH 4.0-9.0 and pH 4.0-8.0, respectively, whereas mannanase was unstable above pH 6.5. In respect to that stability, arabinanase and galactanase were stable below 45°C, whereas mannanase was unstable above 30°C. (3) The koji molds isolated from tane-koji for Shoyu manufacture showed high-level activity of the three hemicellulases. (4) High activity of the three hemicellulases was obtained in the old colonies of deep color of brown or brown-green and of short stokes. (5) Relatively high correlations were seen between arabinase activity and galactanase (1% of risk), neutral protease (1% of risk) and alkaline protease (5% of risk).

View full abstract

Effects of sodium chloride (NaCl) and pH on the rheological properties of synthetic flour dough were investigated. Mixing properties of the dough were determined by using a mixograph and stress relaxation by a microdisplacement meter, respectively. The dough development time of the NaCl-free dough increased with an increase in pH, and the weakening rate decreased with increasing pH. The dough development of NaCl-added sample was accelerated with pH increasing from 4.1 to 5.1 and delayed slightly above pH 5.8. Maximum consistency of the doughs increased as the pH was increased and maximum weakening rates were obtained for the samples of pH 5.1 or 5.8. Minimum relaxation moduli were obtained for the dough of pH 5.8 containing 0-0.4M NaCl and for that of pH 5.1 containing 0.6-1.0M NaCl. The relaxation moduli for the different pH doughs decreased with increasing NaCl concentration up to 0.2 or 0.4M, but increased above these NaCl concentrations. The smallest stress relaxation spectrum was observed for the 0.4M NaCl samples with the all different pHs. This result suggests that the formation of gluten matrix does not develop so much for the samples of this NaCl concentration.

View full abstract

Improvement of production of bean sprouts having heavier (thick) hypocotyls was studied using application of sunlight lamp (Asl). The sprouts of soybean, mung bean, and adzuki bean were cultivated in the dark chambers at 30°C, and the Asl were applied for 60min. every day from 3 days after initiation of cultivation (48 hours after planting) at 500, 2500, 5000, and 10000 luxes. The intermittent application of Asl at 500 lux resulted in an excess of elongation and insufficient thickening of hypocotyls. At 5000 and 1000 luxes, on the other hand, Asl brought a quality deterioration due to excessive suppression of elongation, yellowing, hardening, and accelerated growth of lateral roots, while weight and vitamin C content of sprouts were much incaeased. Asl treatment at 2500 lux, on the contrary, produced excellent sprouts efficiently meeting the market demand, that is, elongation, thickening, and weight increase were accelerated, and vitamin C content was considerably increased. The period needed for cultivation was shortened by 1-2 days as compared with a conventional method. The yellowing and the growth promotion of lateral root were not a serious problem at this illumination intensity.

View full abstract

Koji mold fermentation treatment was investigatied to remove and to mask unpleasant flavor and fishy odor of the enzymatic digest of fish scraps. For koji preparation, cooked wheat bran was mixed with spore of Aspergillus soyae and was kept at 25°C for 48 hrs. To remove the unpleasant flavor of the enzymatic digest of fish scraps, the addition of the completed koji at 30% level and fermentation treatment at 40°C for ten days were required. A clear liquid with good flavor was separated from the fermentation residues by filtration through a synthetic fiber cloth under pressure of 110-111kg/cmcm². The final seasoning solution was cooked up to 80°C and mixed with p-hydroxybenzoic acid buthyl ester at 0.01% for good preservability.

View full abstract

Analytical conditions of FDA method and accuracy for determination of organo-chlorinated pesticide residues (α-BHC, β-BHC, γ-BHC, δ-BHC, pp'-DDT, op'-DDT, pp'-DDE, pp'-DDD, dieldrin, heptachlor and heptachlor epoxide) in milk were studied by gas-chromatography. The following results were obtained. The content of fat obtained by the fat extraction process in FDA method using potassium oxalate was lower than that by ROSE-GOTTLIEB or GERBER method. Therefore fat content should be determined independently by ROSE-GOTTLIEB or GERBER method before analysis of the pesticide residues by FDA method. Volume of injection of test solution to gas-chromatograph considerably influenced on accuracy of analysis. To minimize the error, prescription of the conditions of the response on gas-chromatograph should be recomended. The prescript condition was that on chromatogram more than 30mm of peak height of β-BHC should be obtained when a 1.0μl of O.05ppm standard solution was injected. According to analytical accuracy, expression of the analytical data should be on the second decimal place in ppm for BHC, DDT and heptachlor epoxide, and on the third decimal place in ppm for dieldrin and heptachlor.

View full abstract