How different fractions of soluble ß-glucans from oats affect staling of high oat flour containing breads

Abstract: Introduction. Bread is one of the most consumed foods in the world today. It is also the cause for major food waste streams. Most breads have turned into high glycaemic index products with low nutritional value. This master’s thesis investigated whether the soluble oat fiber ß-glucan (BG) would have positive effects on the abovementioned. There are health claims associated with different doses of BG for positive effects on blood glucose control and ways of preventing cardiovascular disease, but these were not investigated. The idea was that by including extra BG in already high oat flour containing wheat breads, would retard the staling aspects of bread in terms of moisture content, specific volume, springiness, firmness and starch retrogradation. Methods. Breads with a 50-50 blend of oat and wheat flour were baked including two different BG powders with BG concentrations of 32 % (BG32) or 75 % (BG75). The BG was added either as a powder or pre-solubilized in the water prior to mixing with the rest of the ingredients. BG concentrations of 1, 3 and 5 % based on total flour, with corrected water addition for comparable dough stiffness, were analysed. The breads were stored in room temperature for 0, 1 and 3 days before being analysed. All qualities were performed with 6 replicates except for specific volume which was only performed in duplicate. Results and discussion. Multivariate analysis showed positive correlations between the binary addition type of BG and the quality aspects of specific volume and springiness. There was also a positive correlation between a higher moisture content and higher concentration of BG. The latter was however negatively correlated with specific volume and springiness. The amount of storage days were negatively correlated with peak force, meaning that the longer the storage, the softer the breads were compared to their reference bread. The best overall effect was seen for the intermediate BG32 concentration (1.2 % of total weight) added as a powder.