Assessment of the rheological profile of fibre-enriched bread doughs by response surface methodology

The research aims at optimising mixtures of fibres from different sources and degree of processing meeting acceptable dough visco-elastic standards to design low-calorie wheat bread formulations. Effects of soluble-inuline (FN)-, partially soluble-sugar beet (FX), pea cell wall (SW)-and insoluble-pea hull (EX)-dietary fibres on wheat dough mechanical, extensional and surface-related functional profile have been investigated by response surface methodology, and the parameters derived from the functional profile correlated. Flour replacement at different levels (from 6 up to 34%) by fibres significantly change dough machinability and extensional behaviour of the resulting hydrated flour-fibre blends. SW had no relevant significance on dough viscoelasticity when added singly. FX, a fibre with good hydration properties and small particle size, provided the most beneficial effects on dough textural profile, when added singly, especially for the prominent and suitable decrease in gumminess and no significant adverse effects on main mechanical, surface and extensional properties. Caution should be paid to both the pair FX-SX and single EX because of the adverse shortening and hardening effects they respectively induced. Addition of EX to FX-flour blends is not recommended because of the deleterious effect on dough mechanical properties and extensional behaviour, particularly in reducing springiness and cohesiveness. The association of EX and SW, both from pea is strongly encouraged to minimize adhesiveness and stickiness. (c) 2005 Elsevier Ltd. All rights reserved.