Evaluation of baking procedures for incorporation of barley roller milling fractions containing high levels of dietary fibre into bread

Abstract

BACKGROUND: Roller milling of hull-less barley generates fibre-rich fractions (FRF) enriched in non-starch polysaccharides from the endosperm cell walls (β-glucans and arabinoxylans). This investigation was initiated to compare the suitability of different baking processes and to determine the optimal conditions for incorporation of barley FRF into pan bread. RESULTS: Addition of FRF from waxy and high-amylose starch hull-less barley genotypes was evaluated in pan bread prepared from Canada Western Red Spring (CWRS) and Canada Western Extra Strong (CWES) wheat flour. Three bread processes were used: Canadian short process (CSP), remix-to-peak, and sponge-and-dough. Addition of 20% FRF (equivalent to enrichment with 4.0 g of arabinoxylans and β-glucans per 100 g of flour) disrupted dough properties and depressed loaf volume. CSP was not suitable for making FRF-enriched bread because dough could not be properly developed. FRF-enriched remix-to-peak bread was better, especially for the stronger CWES flour. The better bread quality compared to CSP was probably due to redistribution of water from non-starch polysaccharides to gluten during fermentation prior to remixing and final proof. The sponge-and-dough process produced the best FRF-enriched bread because of the positive effect of sponge fermentation on gluten development and hydration. FRF was added at the dough stage to fully developed dough. CONCLUSION: The method of bread production strongly influences bread quality. Pre-hydration of FRF improved bread quality. CWRS and CWES flour produced comparable FRF-enriched sponge-and-dough bread. Addition of xylanase to the sponge-and-dough formula improved the loaf volume, appearance, crumb structure and firmness of FRF-enriched bread. © 2007 Society of Chemical Industry.