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Studies on the physical and chemical properties of dietary fibre in Daucus carota

It has recently been suggested that the occurrence of many organic diseases in the western world could be the result of a low intake of dietary fibre. Dietary fibre, is considered as the cell wall component of plants, varies both quantitatively and qualitatively between species and with the method of fibre preparation. The role of fibre in the diet may relate to its physical properties and those will depend on the chemical composition of the cell wall. The major physical properties are water holding capacity, cation exchange capacity, and organic adsorption ability and the major chemical properties are acid detergent fibre, lignin and cellulose content. It is important to identify these properties before a fibre source can be assessed clinically. In this investigation the carrot root developmental system was used as a fibre source to measure the physical properties of fibre and to determine whether these properties could differ either between varieties or within a variety. No differences were found between varieties but there were differences within each variety; these are probably of little dietary significance. When raw carrot was eaten the only effect that correlated with the physical properties of the prepared fibre was the bile salt adsorption ability. An increase in faecal bile acid excretion was found which continued in the absence of carrot. Serum cholesterol concentration decreased and the effect continued in the absence of carrot. This suggests that vegetable dietary fibre could influence body sterol metabolism. Differences between the nutritional effects of raw carrots and the properties of prepared fibre suggest fermentation by colonic bacteria could alter the properties of dietary fibre.

Identiferoai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:661282
Date January 1978
CreatorsRobertson, James
PublisherUniversity of Edinburgh
Source SetsEthos UK
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation
Sourcehttp://hdl.handle.net/1842/14306

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