NIPPON SHOKUHIN KOGYO GAKKAISHI

Studies on the tannins of Fruits and Vegetables

Part XI. Adsorption of tannins with chitin

TOSHIO NAKABAYASHI, TERUO MAKITA

1972 Volume 19 Issue 3 Pages 111-116
Published: March 15, 1972
Released on J-STAGE: March 08, 2010

DOIhttps://doi.org/10.3136/nskkk1962.19.111

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The absorbability of tannin with chitin which is known as an insoluble agent, was studied. The tannin removing ability of chitin was little affected by pH in the range of pH 3-7, however its ability was reduced with the temperature increase. It was also reduced with the presence of sucrose and ethanol, however it was increased with the presence of sodium chloride.
When chitin was coated on celite, its absorption efficiency was greatly improved. Since chitin poorly absorbed low molecular polyphenolics, such as catechin and chlorgenic acid, but well absorbed ordinary tannin, the majority of tannin existed in fruits extracts were removed with chitin treatment and only the low molecular polyphenolics were left in the extracts as a residue. It is, therefore, supposed that chitin will be utilized as an astringency removing agent of fruit or vegetable juices.
Chitosan, the deacetylated product from chitin, showed stronger activity than chitin, however it is not recommended to use chitosan for practical purpose, since it was dissolved in an acidic solution pH less than 4 and did not precipitate tannin.

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Studies on the Dried Agar Jelly

Part I. Effects of the cooling temperature on the physical properties of agar jelly

KINICHI ISHIDA, ICHIZO SHIGA

1972 Volume 19 Issue 3 Pages 117-121
Published: March 15, 1972
Released on J-STAGE: January 20, 2010

DOIhttps://doi.org/10.3136/nskkk1962.19.117

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Changes of the gel strength of agar jelly cooled at different temperatures were measured by an Autograph.
On gelation at 10°C, 20°C and 30°C, the gel strength of agar jelly was increased corresponding to rise of its cooling temperature and the more the cooling temperature was lowered the more the gel was settled rapidly to final rigidity.
When the cooling temperature was changed from 30°C to 20°C or 10°C on cooling process, the ge1 strength of agar jelly was higher than that cooled at 20°C or 30°C throughout, but when cooled at 10°C on first stage, the gel strength was lower and its values was unchanged even if cooling temperature was increased to 20°C thereafter.
When cooled at 40°C, the gel strength was decreased as the retention time proceed.

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Studies on the Dried Agar Jelly

Part II. Examination of shortening of cooling time

KINICHI ISHIDA, ICHIZO SHIGA

1972 Volume 19 Issue 3 Pages 122-126
Published: March 15, 1972
Released on J-STAGE: January 20, 2010

DOIhttps://doi.org/10.3136/nskkk1962.19.122

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To examine the possibility to shorten the cooling time on the dried agar jelly manufacturing, changes of the physical properties such as gel strength (g/cmcm²), gel strain/gel strength (Y/G, cm⁸/g), Young modulus (dyne/cmcm²) and viscosity (poise) of agar jelly on cooling stage were measured.
On water cooling, changes of the gel strength and Y/G values of agar jelly were little after cooled for seven hours.
Cooling rate of agar jelly on water cooling and air cooling was measured. The time required until jelly cooled to 20°C by air was three times that of water, and the gel strength by air cooling was higher than that of water.
From those experimental results, it was considered that the cooling time of agar jelly on the present experimental condition can be shortened to seven hours.

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