Читать книгу Whole Grains and Health - Группа авторов - Страница 26

Sourdough fermentation provides improved flavour and structure to rye and wheat bread. In the case of rye, the swelling of flour constituents is favoured and the enzyme activity is limited under acid conditions, which prevents early staling (Narvhus and Sørhaug 2012). The interest in the significant potential of sourdough fermentation to improve the nutritional properties of rye, oat and wheat products is increasing nowadays (Komlenić et al. 2012). The whole grain or fractions of cereal grain can be modified by sourdough fermentation to improve nutritional value or promote healthfulness of cereal foods (Chavan and Chavan 2011). Sourdough fermentation has been associated to positive effects in whole grain bread such as improved of palatability, mineral bioavailability and levels of bioactive compounds, and reduction of starch digestibility (Poutanen et al. 2009). The ability of sourdough processing to reduce starch digestibility is assumed to be mainly due to formation of organic acids, especially lactic acid, during fermentation (Liljeberg et al. 1995).

Specific modifications in baked product texture can be achieved by development of new sourdough cultures, and by optimizing acidity and interactions with grain components. As reported by Katina et al. (2005), the changes in dough structure over time can not only be detected by small deformation viscoelastic measurements, but also by confocal laser‐scanning microscopy. The protein fraction of the gluten‐free sourdough is degraded over time, although this process is more obvious in wheat sourdough (Clarke et al. 2004). However, the addition of sourdough to gluten‐free batters does lead to an improvement of the gluten‐free‐bread (Katina et al. 2005).