Lupin flour as a wheat substitute in conventional and sourdough breadmaking: impact on bread physicochemical properties and volatile profile

Abstract Enhancing the nutritional profile of baked goods while addressing sustainability challenges means finding different sources of functional, sensory and nutritional ingredients. The aim of this study was to evaluate native lupin flour versus spontaneously fermented lupin flour as ingredient for wheat breadmaking. For that purpose, wheat flour was supplemented with 15–30 g/100 g lupin flour (LF15, LF30) or freeze-dried lupin sourdough (LS15, LS30) and dough and breads were assessed in comparison with wheat bread (control). Both lupin flour and lupin sourdough decreased dough stability, delayed the fermentation and lowered the pH. The incorporation of lupin flour increased the hardness of the crumb, except for when adding sourdough (15 g/100 g) that increased the bread expansion and enriched the volatile profile of bread. The analysis of the volatile compounds confirmed that lupin flour conferred fatty, green odor due to octanal, and when in the form of sourdough brought sour, and almond notes from acetic acid and benzaldehyde, respectively. Overall, lupin addition is a strategy to produce bread aligned with current trends towards sustainable and plant-based diets, particularly in the form of spontaneous type IV whole lupin sourdough up to 15 g/100 g wheat replacement.