title: Effect of carrot (Daucus carota) microstructure on carotene bioaccessibility in the upper gastrointestinal tract. 2. In vivo digestions.
abstract: Nutrient bioaccessibility and subsequent absorption will be directly influenced by changes in food structure during gastrointestinal processing. The accompanying paper (Tydeman et al. J. Agric. Food Chem. 2010, 58, doi: 10.1021/jf101034a) reported results on the effect of carrot processing on the release of carotene into lipid phases during in vitro gastric and small intestinal digestions. This paper describes results from in vivo digestion of two of the types of processed carrot used previously, raw grated carrot and cooked carrot mashed to a puree. Ileostomy effluents from human volunteers fed meals containing the carrot material were used to study tissue microstructure and carotene release. Raw carrot shreds and intact cells that had survived the pureeing process were identifiable in ileal effluent. The gross tissue structure in the shreds had not changed following digestion. Carotene-containing particles remained encapsulated in intact cells, but were absent from ruptured cells. Microscopy revealed marked changes to the cell walls including swelling and pectin solubilization, which increased in severity with increasing residence time in the upper gut. These observations were entirely consistent with the in vitro observations. It was concluded that a single intact cell wall is sufficient to reduce carotene bioaccessibility from a cell by acting as a physical barrier, which is not broken down during upper gut digestion.
authors.affiliation: Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, United Kingdom.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Tydeman
authors.forename: Mary L
authors.initials: ML
authors.lastname: Parker
authors.forename: Richard M
authors.initials: RM
authors.lastname: Faulks
authors.forename: Kathryn L
authors.initials: KL
authors.lastname: Cross
authors.forename: Annette
authors.initials: A
authors.lastname: Fillery-Travis
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Gidley
authors.forename: Gillian T
authors.initials: GT
authors.lastname: Rich
authors.forename: Keith W
authors.initials: KW
authors.lastname: Waldron
mesh_terms: D000328:Adult; D000368:Aged; D001682:Biological Availability; D002338:Carotenoids / Q000493:pharmacokinetics*; D018552:Daucus carota / Q000737:chemistry; D041981:Gastrointestinal Tract / Q000378:metabolism*; D006801:Humans; D008875:Middle Aged
chemical_list: D002338:Carotenoids