1993 Fiscal Year Final Research Report Summary
Fine structure of polysaccharides obtained from dietary fibers.
| Project/Area Number |
03680054
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
家政学
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| Research Institution | Hirosaki University |
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Principal Investigator |
KATO Yoji Hirosaki University, Faculty of Education, Department of Home Economics, Associate Professor, 教育学部, 助教授 (20194863)
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| Project Period (FY) |
1991 – 1993
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| Keywords | Dietary fiber / Xyloglucan / Inulin / Edible burdock / Polysacchride / Diffusion speed / Leaf vegetables / Root vegetables |
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| Research Abstract |
From the viewpoint of the physiological function of dietary fiber, it is important to elucidate the structure and properties of cell wall polysaccharides. In this research project, we obtained the following results.
(1) Carbohydrates in leaf vegetables (cabbage, chainease cabagge, spinach, chingentsuai and lettuce) and root vegetables (turnip, japanese radish, edible burdock, carrot and east indian lotus) were compared in triturated, freeze-dried samples. Fractionation of the carbohydrates, and the sugar composition an sugar-linkage composition analyzes of the fractions suggested that their basic constituent polysaccharides were almost the same. The cell walls consisted of rhamnogalacturonan with side chains, (1->5)-linked arabinan, (1->4)-linked galactan, arabinogalactan, xyloglucan and cellulose.
(2) A xyloglucan was isolated from 24% KHO extract of gobo (edible burdock). A methylation analysis and enzymic degradation studies on the polysaccharide showed that gobo-xyloglucan was built
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up predominantly of repeating-oligosaccharide units of hepta-(Glc : Xyl=4 : 3), nona-(Glc : Xyl : Gal : Fuc=4 : 3 : 1 : 1) and deca-(Glc : Xyl : Gal : Fuc=4 : 3 : 2 : 1)saccharides in an approximate molar ratio of 14 : 12 : 5, which are the typical structural units of dicot xyloglucans.
(3) The chemical structures of xyloglucans obtained from cabbage, chainease cabagge, spinach, chingentsuai and lettuce were compared. Their basic structures were almost the same.
(4) Inulin in edible burdock was hydrolyzed in vivo by enzyme(s) to yield lower molecular weight carbohydrates during storage or heating.
(5) The glucose diffusion speed decreased in vitro as the concentration of the water insoluble dietary fiber increased. This was considered to be due to the permiability of the water-insoluble dietary fiber to lower-molecular weight carbohydrates.
(6) A glucuronoxylan was isolated from jojoba hull. Methylation analysis and enzymic degradation studies of the polysaccharide showed that jojoba hull xylan has a linear chain of (1->4)-D-xylosyl residues in the backbone, about 13% of which are branched at 0-2 position, with 4-0-methyl-alpha-D-glucopyranosyluronic acid residues.
(P.T.O.) Less
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