2007 Fiscal Year Final Research Report Summary
Influence of cooking and intake method on physiology function appearance of dietary fiber
Project/Area Number |
18500608
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Research Category |
Grant-in-Aid for Scientific Research (C)
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Allocation Type | Single-year Grants |
Section | 一般 |
Research Field |
Eating habits, studies on eating habits
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Research Institution | Gifu Women's University |
Principal Investigator |
YAMANAKA Natsumi Gifu Women's University, Department of Home Economics, Professor (00257528)
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Project Period (FY) |
2006 – 2007
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Keywords | soluble dietary fiber / insoluble dietary fiber / viscosity / sweet potato / steaming / microwave-heating / fermentability / digestibility |
Research Abstract |
The amount and physical properties of the dietary fiber contained in foods has a large effect on the physiological functions of those foods when they are ingested. However, the amount and properties of dietary fiber are changed by the process of preparing and cooking food. Using sweet potatoes, which have a fairly high dietary fiber content and need to be cooked before they are eaten, this study investigated how differences in cooking method affect dietary fiber properties, as well as how those properties affect physiological functions. The amount of dietary fiber was measured in raw sweet potatoes and sweet potatoes cooked by steaming and in a microwave oven. Insoluble dietary fiber tended to increase with heating, and tended to increase more in steamed sweet potatoes, in which cooking time was long, that in microwaved sweet potatoes, in which cooking time was short. The soluble dietary fiber of sweet potatoes heated in a microwave oven tended to have higher viscosity than raw or steam
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ed sweet potatoes. It is possible that the rapid rise in temperature in microwave cooking changed the properties of soluble dietary fiber. The effect of these differences in the properties of dietary fiber on the fermentability of dietary fiber was investigated, and it was found that the highly viscous soluble dietary fiber of sweet potatoes heated in a microwave oven had low fermentability. Additionally, freeze-dried sweet potatoes that had been heated with different methods were added to feed which was then given to rats. After 10 days of this feed, we compared the effects it had on the shape and function of the gastrointestinal tract. Tissue weight was taken as an indicator of the effect on the shape of the gastrointestinal tract. The tissue weight of the intestinal cecum and proximal colon was found to have increased with the ingestion of sweet potatoes, but no effect was seen from the differences in heating method. However, the tissue weight of the distal colon increased only in rats that had eaten sweet potatoes cooked by steaming, which had a high content of insoluble dietary fiber, indicating that the effect is different depending on the cooking method. Feed efficiency and the level of fat in the blood were measured as indicators of the effects on digestive absorption function, but no effect was seen with ingestion of any of the sweet potatoes or differences in cooking method. Less
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Research Products
(6 results)