Use this URL to cite or link to this record in EThOS:
Title: Plant cell walls as barriers to lipid bioaccesibility in model lipid-rich plant food (almond)
Author: Grundy, Myriam Marie-Louise
ISNI:       0000 0004 5368 2682
Awarding Body: King's College London
Current Institution: King's College London (University of London)
Date of Award: 2014
Availability of Full Text:
Access from EThOS:
Access from Institution:
It is generally assumed that most of the nutrients contained in a food are released (bioaccessible) during digestion and potentially available for absorption. However, the structure of plant food such as almonds, in particular the cell walls (‘dietary fibre’), may encapsulate intracellular nutrients, thereby limiting their bioaccessibility. The main aim of the studies described in this thesis was to investigate the role played by almond cell walls in the regulation of lipid bioaccessibility and digestion kinetics using a combination of in vivo, in vitro and in silico methods. The particle size distributions of masticated whole raw and roasted almonds collected from 15 volunteers were used to predict lipid bioaccessibility from a mathematical model. Predicted values were compared with experimental measurements of lipid release in the same almond samples. Samples of masticated almonds were then loaded into a dynamic gastric model followed by a static duodenal model to determine lipid loss in these compartments. The rate and extent of lipolysis were measured by pH-stat titration and gas liquid chromatography of released fatty acids on almond materials with different degrees of bioaccessibility under simulated duodenal digestion conditions. The effect of processing on lipid losses and almond microstructure was also determined in ileostomy subjects who consumed two almond meals varying in lipid bioaccessibility. Finally, the potential penetration of lipase(s) through the cell wall matrix was investigated using notably confocal microscopy. The findings of this project indicated that following mastication and gastrointestinal digestion of whole almonds, only a small proportion of lipid was released from ruptured cells. Depending on the almond structure and degree of processing, the amount of lipid released from the food matrix and fatty acids produced from lipolysis varied substantially. This work has provided further evidence that cell walls act as a physical barrier that limits nutrient digestion.
Supervisor: Ellis, Peter Rory ; Berry, Sarah Elizabeth Emma Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available