The effect of replacing part of the wheat flour with a resistant starch rich ingredient (RSRI) - a source of functional fibre with potential health benefits - was studied in short dough biscuits. A control with no replacement and 3 formulations in which 20, 40 and 60g of flour per 100 g were replaced by an RSRI (samples 20RSRI, 40RSRI and 60RSRI) were prepared. From a technological point of view, the RSRI level influenced the consistency of the raw dough and the ease of sheeting and cutting. Regarding the eating quality of the final product, addition of the RSRI increased the breaking strength and crumbliness and reduced the resistance to penetration. In the RSRI biscuits, both the surface and the crumb were paler. The sensory acceptance of the 20RSRI biscuits did not differ significantly from that of the control. 40RSRI reduced the acceptability of the colour, appearance and texture without altering the taste, sweetness and overall acceptance. Neither of these two levels significantly reduced the consumption intention. However, 60% flour replacement produced biscuits with lower sensory acceptability and a significant reduction in consumption intention. In general, the results could be interpreted in terms of the protein-diluting effect of the added ingredient and changes in the water content and water-retention capacity of flour mixtures containing RSRI. The present results proved that resistant starch rich ingredients (RSRI) have good potential for developing fibre-rich biscuits without changing their general features.

The authors are grateful to the Spanish Ministry of Science and Innovation for financial support (AGL2009-12785-C02-01), to National Starch for kindly supplying the RSRI sample and to Mary Georgina Hardinge for assistance with the English-language manuscript.