Food macro-molecules in planta are enclosed within cells encapsulated by cellulosic and pectic cell walls. The intactness of these “natural capsules” modulates the metabolic responses, digestion and fermentation in the GI tract. The structure of the capsule, however, depends on physical and thermal processing. Using this lowest structural level, “intact plant cell”, we demonstrated how the alteration of cellular structure could affect the in-vitro digestion of starch and protein, change in the rate of fermentation, production of metabolites (e.g. short-chain fatty acids) and alteration in gut-microbial population. Intact pulse cells were isolated and subjected to physical force (shearing) to completely destroy the barrier and thermal processing at varying temperatures for a controlled increase in the cell wall porosity. The physically altered cells were subjected to standard in-vitro digestion and faecal fermentation using human faeces as the inoculum. The rate of digestion of starch, protein, rate of fermentation, generation of metabolites (short-chain fatty acids) and shift in the microbial population (phylum, genus and species) were investigated The cell wall provided a strong barrier for enzyme diffusion during in-vitro digestion. Thus the rate and extent of starch and protein digestion were significantly higher for broken cells compared to intact cells. The effect, however, was more pronounced for starch compared to proteins, suggesting the slow protease action on less denatured proteins. With the increase in cell porosity using the thermal process, the rate of fermentation, production of SCFA and microbial diversity increased. Most noticeably, a significant rise in Bifidobacterium was observed with an increase in porosity of pulse cells, consistent with increased SCFA production. The result shows that the cell wall provides a barrier for intestinal digestion and colonic fermentation, and increased porosity induces catalysis of macro-nutrients due to more accessible substrate. Thus, desired glycaemic response and colonic fermentation profiles can be achieved with the controlled processing of whole foods for enhanced metabolic and gut health

In planta encapsulation of macro-nutrients for enhanced nutritional functionality

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.