The end products of dietary fibre fermentation by the gut microbiota are short-chain fatty acids (SCFA), mainly acetate, propionate, and butyrate and they are important for various physiological pathways that take place within our bodies. Short-chain fatty acids also help in the regulation of intestinal tight junctions which are the initial instruments of defence for our immune system. The epithelial layer (outer layers of intestinal cells) are connected by structures called tight junctions which firmly adhere adjacent epithelial cells to one another forming a seal that prevents macronutrients such as proteins and other ions to escape from within the intestinal lumen into our bloodstream without a screening process. Normally, when things are all functioning correctly in our digestive process, the fully sealed tight junctions ensure precise control over which macronutrients are passed through the epithelial cells from our intestines into our bloodstream (I tend to think of them as being like bouncers at a night club door). Short-chain fatty acids also form important flavour compounds in the sourdough process of bread-making. Two main short-chain fatty acids that contribute significantly to the flavour of bread crumb are 2-methyl-propanoic acid, 3-methyl- butanoic acid.
One of the recipes you can bake where you can literally taste SCFA is in our Sourdough Shortcrust Pastry Recipe