Cereal Arabinoxylans-Their Enzymatic Degradation and Relevance for Breadmaking and Human Health

As the most abundant nonstarch polysaccharides in cereals, arabinoxylans (AXs) contribute significantly to the global intake of dietary fiber. They play a crucial role in the breadmaking process with respect to dough rheology and texture, bread volume, and nutritional quality, especially when starting from wheat or rye flour. During (sour)dough preparation, AX-degrading enzymes from either endogenous or microbial origin are activated, causing changes in the AX composition and structure that, in turn, affect the viscosity and gas retention capacity of the bread dough. These effects lead to beneficial changes in dough handling, which may improve bread volume and crumb texture. The production of sourdough-based breads represents an interesting case. The sourdough microbiota, consisting primarily of lactic acid bacteria and yeasts, may substantially contribute to AX alteration by either producing AX-degrading enzymes or contributing to the acid-mediated activation of endogenous ones as a result of dough acidification upon fermentation of the flour-water matrix. To monitor the quantity, composition, and structure of AXs during (sourdough) bread production, various methods and analytical techniques have been developed. A better understanding of the fate of AXs during sourdough production and of the specific AX-affecting capabilities of the microorganisms that inhabit the sourdough ecosystem may allow for better control and steering of the breadmaking process, resulting in more standardized bakery products of improved quality.