Bread is a major staple food consumed daily in all parts of the world. A significant part of the human population cannot tolerate gluten, a storage protein found in wheat, rye and barley, and therefore, products made from alternative cereals are required. During this study, the bread-making potential of seven gluten-free flours, wheat and wholemeal wheat flour was compared. Fermentation potential of the different flours was determined, showing that dough development height of gluten-free and wholemeal wheat samples was lower than for wheat and oat flour. Apart from standard bread quality parameters such as loaf-specific volume and physical crumb texture, also water activity and shelf life have been determined. The shelf life of gluten-free breads was reduced compared to wheat bread. Aroma profiles were evaluated by a trained panel. Wheat, oat and wholemeal wheat breads were liked moderately, while the remaining samples had lower liking scores. Crumb grain characteristic s were investigated using image analysis, and microstructure was observed by scanning electron microscopy. Overall, only breads produced from oat flour were of similar quality to wheat bread, and the utilization of buckwheat, rice, maize, quinoa, sorghum and teff flours resulted in breads of inferior quality

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Gluten-free flours (buckwheat, quinoa, sorghum and teff) were fermented using obligate heterofermentative strain Weissella cibaria MG1 (Wc) and facultative heterofermentative Lactobacillus plantarum FST1.7 (Lp). Starch hydrolysis of breads with and without sourdough (controls) was analyzed in vitro using enzymatic digestion followed by dialysis (10-11 kDa). Hydrolysis indices as well as predicted glycemic indices (pGI) were calculated from reducing sugars released into the dialysate. Amounts of resistant starch (RS; % of total starch) were determined by enzymatic digestion. Upon sourdough addition, RS significantly decreased in buckwheat (Wc 1.28%, Lp 1.44%) and teff sourdough breads (Wc 0.87%, Lp 0.98%) in comparison to their controls (2.01% and 1.92%, respectively). However, no correlation was found with starch hydrolysis. Predicted GIs were reduced upon sourdough addition in wheat (ctrl 100; Wc 85; Lp 76) in comparison to control breads. This was not the case in most gluten-free breads with the exception of sorghum (ctrl 72; Lp 69) and teff sourdough breads (ctrl 74; Lp 68). In contrast, increased pGIs were found in quinoa (ctrl 95; Wc 106; Lp 103) and buckwheat sourdough breads (ctrl 80; Wc 89; Lp 86).

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