Moringa oleifera L. leaf powder as ingredient in gluten-free biscuits: nutritional and physicochemical characteristics

Dried powder from Moringa oleifera L. leaves (MOLP) could be considered a promising naturally gluten-free (GF) ingredient to be added in the formulation of GF food products aiming to improve the overall nutritional characteristics. In this work, GF biscuits were formulated by replacing a commercial GF flour mix with 0, 5, 10, and 15 g/100 g of MOLP. Chemical composition, physical and textural characteristics, starch pasting properties, and the in vitro starch digestibility were considered. Adding MOLP increased the amount of protein and total dietary fibre. Even at the lowest MOLP-substitution level, the biscuits had a total dietary fibre content > 6 g/100 g dry matter. Differences in the chemical composition might account for differences in starch properties in terms of pasting behaviour and in vitro digestibility. Using MOLP decreased the in vitro starch hydrolysis index of biscuits, the lowest value (69.3) obtained at the greatest MOLP inclusion level. In addition, an increase in the resistant starch content was reported, passing from 1.1 to 2.7 g/100 g dry matter for GF biscuits containing 0 to 15 g/100 g of MOLP. Colour, spread ratio, and hardness were affected by MOLP inclusion. Biscuits containing 15 g/100 g of MOLP were characterized by the highest hardness value (41.9 N). Substitution level of 10 g/100 g should be considered the threshold level for obtaining a product with similar spread ratio than the control.