Reference Number: 9
Year: 2009
Link: Link to original paper
Nutrition: Amino Acids | Bioactive peptides | Fibre | Minerals | Phytic acid | Resistant starch | Vitamins
Summary
Summary
Use of sourdough is of expanding interest for improvement of flavour, structure and stability of baked goods. Cereal fermentations shows significant potential in the improvement and design of the nutritional quality and health effects of foods and ingredients. In addition to improving the sensory quality of whole grain, fibre-rich or gluten-free products, sourdough can also actively retard starch digestibility leading to low glycemic responses, modulate levels and bioaccessibility of bioactive compounds, and improve mineral bioavailability. Cereal fermentation may produce non-digestible polysaccharides, or modify accessibility of the grain fibre complex to gut microbiota. It has also been suggested that degradation of gluten may render bread better suitable for celiac persons. The changes in cereal matrix potentially leading to improved nutritional quality are numerous. They include acid production, suggested to retard starch digestibility, and to adjust pH to a range which favours the action of certain endogenous enzymes, thus changing the bioavailability pattern of minerals and phytochemicals. This is especially beneficial in products rich in bran to deliver minerals and potentially protective compounds in the blood circulation. The action of enzymes during fermentation also causes hydrolysis and solubilisation of grain macromolecules, such as proteins and cell wall polysaccharides. This changes product texture, which may affect nutrient and non-nutrient absorption. New bioactive compounds, such as prebiotic oligosaccharides or other metabolites, may also be formed in cereal fermentations.
SIGNIFICANCE OF THIS STUDY
This paper demystifies the role of sourdough fermentation on the textural and nutritional quality of baked products.The first motives for use of fermentation in baking were leavening, flavour formation, and improved stability. In the recent years, more research has advanced around the areas of sourdough fermentation in enhancing nutrition and health properties. Although large scale clinical trials on the effects of sourdough baked products on health and nutrition in humans are limited, the information so far still seems valuable. Examples include, fermentation and acid production by lactic acid bacteria and yeast have been shown to bring about improved mineral bioavailability. Sourdough and yeast fermentation may also increase the levels of bioactive compounds such as certain health promoting peptides, but here more research is warranted. Sourdough baking is also consistently shown to deliver breads with slower starch digestibility and hence low glycemic responses, and has shown promise in improving texture of gluten-free bread for celiac patients. The extracellular polysaccharides produced by lactic acid bacteria could act as selective or functional substrates for gut microbiota. It can therefore be anticipated that sourdough processing could be used to design foods with specific gut-mediated health effects, such as demonstrated changes in composition or activity of intestinal microbiota.
