Reduced-fat biscuits : interplay among structure, nutritional properties and sensory acceptability

This work aimed at investigating relationships among structure, nutritional properties, and sensory acceptability of reduced-fat biscuits in comparison with a full-fat biscuit (STD). Four reduced-fat formulations were tested: OPT (46.3% fat reduction), an optimized formulation containing polydextrose and resistant starch; RAW and EXTR, obtained by substituting resistant starch with raw and extruded bean powders, respectively; WOW, in which a double emulsion was used instead of shortening. Fracture strength resulted comparable in STD and OPT, but increased for the other samples due to the structuring role of bean protein or the very low amount of fat. Scanning Electron Microscopy images revealed a well-developed protein structure in all samples, except for WOW that presented a more continuous and closed network. EXTR showed the lowest level of rapidly digestible starch and lipid digestibility. RAW showed the highest protein digestibility, significantly different from STD (12.1 ± 2.7 vs 3.7 ± 1.6 g/100 g proteins). Thanks to the holistic approach used, the influence of fat content on dough and biscuit structure as well as on colour was assessed, demonstrating also an effect on nutritional properties and consumers’ acceptance.