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Volume 21, Issue 12
Displaying 1-6 of 6 articles from this issue
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Part IV. Pungency of piperineYASUO YAMAMOTO1974 Volume 21 Issue 12 Pages 579-584
Published: December 15, 1974
Released on J-STAGE: June 23, 2010
JOURNAL FREE ACCESSPungency of black pepper is due to piperine and its cis-isomers give almost no heat. Threshold level of pungency of piperine is 5 to 10ppm which is almost the same level of its solubility in water (6.2μg/ml).
Crystalline piperine which is easily crystallized shows almost no pungency, while piperine, which is dissolved or dispersed minutely in water so much as to give enough stimulus to the nervous cells on tongue, has strong heat. For example its alcoholic solution gives very strong heat immediately after poured into water and loses its pungency after crystallization.
By model experiments (such as piperine in solution, in starch paste, in the presence of edible oils, adsorbed on filter paper and so on) it was observed how different states of piperine showed different degrees of pungency.
It was assumed that loss of pungency of ground pepper during storage is due to the gradual crystallization of piperine which had been dissolved in essential oils or oily by-alkaloids in pepper, although it has been attributed to gradual isomerization of chavicine into piperine by NEWMAN or piperine into isochavicine by CLEYN.View full abstractDownload PDF (321K) -
KEI YAMANAKA1974 Volume 21 Issue 12 Pages 585-591
Published: December 15, 1974
Released on J-STAGE: January 20, 2010
JOURNAL FREE ACCESSChanges of color intensity during the refining steps of raw sugars were analyzed by a Nihon Denshoku digital color machine, model ND-101D using the white standard plate (X 83.7%, Y 82.1%, Z 94.8%). Whiteness was increased gradually by each refining step, and final sample showed 0.34 and 0.35 as x and y values, respectively, and 77-80% as whiteness.
Particle distributions were also analyzed by sieving method. While the larger particles (2.0-4.0 and over 4.0mm in diameter) were rapidly decreased with polishing mascuite with hand, the smallest particles (less than 0.25mm in diameter) were gradually increased. Under microscopic observation on each fractionated particle, there was no single crystal larger than 0.4mm even in raw mascuite. The bigger particles were clusters of small crystals to which decomposed with polishing. This is one of the characteristics of the traditional refining process. Final products were composed of mainly particles of less than 0.25mm and 0.25-0.50mm in diameter 41-65% and 21-33%, respectively.View full abstractDownload PDF (2078K) -
Part III. Radiosterilization of protease preparationsKOJI KAWASHIMA, YOSHIKAZU TANAKA, KEIJI UMEDA1974 Volume 21 Issue 12 Pages 592-596
Published: December 15, 1974
Released on J-STAGE: January 20, 2010
JOURNAL FREE ACCESSEnzyme preparation are frequently contaminated with various microorganisms. However, their sterilization is rather difficult to be performed due to the easy heat inactivation of enzymes. Radiation sterilization is a cold sterilization procedure and in this paper some protease preparations are irradiated with Co-60 gamma ray for the elimination of microorganisms.
1. Nine commercial protease preparations were irradiated in a ice water bath with a sterilization dose of 0.75-1 Mrad. Out of these, seven proteases retained activity of more than 95%, whereas the other two retained activity of about 95 and 80%. Thus it is considered that radiosterilization is possible in the case of protease preparations.
2. The moisture contents of proteases had no effects on the radiosensitivity of enzymes. 3. Some proteases showed an increase activity range of 4-60% during radiosterilization at a dose of 250 Krad.
4. No differences in the heat stability were observed between irradiated and non-irradiated protease preparations.
5. On storage for 2 months at 5°C irradiated proteases recovered their activities to a considerable extent.View full abstractDownload PDF (242K) -
Part I. Changes of brown rice and milled rice during storageNAOTO SHIBUYA, TETSUYA IWASAKI, HAJIME YANASE, SHINJIRO CHIKUBU1974 Volume 21 Issue 12 Pages 597-603
Published: December 15, 1974
Released on J-STAGE: January 20, 2010
JOURNAL FREE ACCESSQuality changes of brown rice and milled rice were comparatively studied by determining several properties indicating rice quality.
Fat acidity of milled rice increased more rapidly than brown rice. Changes in the acidity of the water extract showed the similar trend. Gas chromatographic analysis of the head space vapor of the cooked rice revealed that the content of the main stale flavor component of milled rice, n-caproaldehide, was almost doubled as compared with brown rice.
On the contrary, changes in rheological properties of cooked rice or its paste during storage measured by a texturometer or an amylograph were almost the same in brown rice and milled rice. No significant relationship was observed between free fatty acid content and rheological properties of rice grain or rice flour. It was suggested from these results as to the following items:
(1) Changes in flavor and taste of milled rice during storage were greater than those of brown rice.
(2) Free fatty acid content could hardly account for the changes in rheological properties of cooked rice and its paste during storage.View full abstractDownload PDF (361K) -
SACHIO HAYAKAWA, TATSUO HIRABAYASHI, HISAO WATANABE1974 Volume 21 Issue 12 Pages 604-607
Published: December 15, 1974
Released on J-STAGE: March 08, 2010
JOURNAL FREE ACCESSMethylesters of organic acids prepared from Royal-jelly and its processed products were analyzed by gaschromatography (FID). Six peaks were detected in the chromatogram. Since peak F was found to show the same retention time as that of nona-decanoate the amount of peak Fsubstance was estimated as nona-decanoate. A method of estimation of Royal-jelly content in its processed products based on the analysis of peak F-substance was discussed.View full abstractDownload PDF (165K) -
1974 Volume 21 Issue 12 Pages 608-614
Published: December 15, 1974
Released on J-STAGE: April 21, 2009
JOURNAL FREE ACCESSDownload PDF (560K)
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