Positive health effects of dietary fibre have been established; however, the underpinning mechanisms are not well understood. Plant cell walls are the predominant source of fibre in the diet. They encapsulate intracellular starch and delay digestive enzyme ingress, but food processing can disrupt their structure. Here, we compare the digestion kinetics of chickpea (cotyledon) and durum wheat (endosperm), which have contrasting cell wall structures (type I and II, respectively), to investigate a cell wall barrier mechanism that may underpin the health effects of dietary fibre. Using in vitro models, including the dynamic gastric model, to simulate human digestion, together with microscopy, we show that starch bioaccessibility is limited from intact plant cells and that processing treatments can have different effects on cell integrity and digestion kinetics when applied to tissues with contrasting cell wall properties. This new understanding of dietary fibre structure is important for effective fibre supplementation to benefit human health.
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Source data are provided with this paper. The other datasets generated and/or analysed during the current study are available from the corresponding author upon reasonable request.
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We thank Premier Analytical Services (The Lord Rank Centre, High Wycombe, UK) for proximate analysis data on the wheat and chickpea samples, G. Campbell and S. Galindez-Najera (at the University of Manchester) for technical expertise, assistance and the use of facilities for preparation of the milled materials, G. Vizcay-Barrena from the Centre for Ultrastructural Imaging at King’s College for sectioning microscopy samples, and the Model Gut team at the Institute of Food Research (now Quadram Institute Bioscience) for use of the DGM and SDM. This project was funded by the Biotechnology and Biological Sciences Research Council (BBSRC) (DRINC; BB/H004866/1) and C.H.E. was in receipt of a BBSRC CASE studentship award with Premier Foods (UK) as an industrial partner. C.H.E. gratefully acknowledges support from the BBSRC Institute Strategic Programme Food Innovation and Health (BB/R012512/1) and its constituent project (BBS/E/F/000PR10345).
The authors declare no competing interests.
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Edwards, C.H., Ryden, P., Mandalari, G. et al. Structure–function studies of chickpea and durum wheat uncover mechanisms by which cell wall properties influence starch bioaccessibility. Nat Food 2, 118–126 (2021). https://doi.org/10.1038/s43016-021-00230-y