Incorporation of high fibre ingredients into gluten-free bread

Gluten-free (GF) breads tend to be purely starch-based and in general are nutritionally poor; hence their enrichment with dietary fibres is imperative. The objective of this study was to examine the effects of the addition of high fibre ingredients to a GF bread formulation, based on rice flour, potato starch, skimmed milk powder and hydrocolloids. Five different fibres, apple fibre (AP), oat bran (OTF), oat bran containing 10% beta-glucan (BG10), oat bran containing 15% beta-glucan (BG15) and oat fibre (OTG) were examined at 5 and 10 % (flour basis) addition levels. The consistency of the GF batters was standardized using fundamental rheological tests (single frequency). Standard baking tests such as bake loss (%), specific volume (ml/g), crust colour (L*), crumb moisture (%) and image analysis were measured. The staling properties of the breads were determined using texture profile analysis over a 5-day period. Results showed, for all the GF batters, a significant increase in the level of water with increasing fibre (P < 0.05). With regards to the baking characteristics, significant differences were found between the control GF (no fibres) and the fibre containing GF bread (P < 0.05). Furthermore, significantly higher bake loss and crumb moisture values were found for each fibre (P < 0.05). Correlations were detected between crumb moisture and cohesiveness after 5 days of storage (R = 0.83, P < 0.05). The specific volume was significantly improved for BG10, BG15 and OTF at 5% and 10%. In comparison, the AP (5%) and AP (10%) exhibited significantly lower specific volumes (P < 0.05). Significantly lower crumb hardness values, with the exception of AP (5%) were found for the fibre containing GF breads over 5 days in comparison to the control (P < 0.05). The most promising results were found for the OTF (10%), OTF (5%) and BG10 (10%) GF breads. Overall, it can be concluded that the addition of fibres enhanced the quality of the GF breads by decreasing their crumb staling.