Investigating the suitability of lupin flour and lupin type iv sourdough substitution in bakery products

Lupin flour is considered an innovative source of protein, fiber and micronutrients, with distinguishable nutritional, technological and organoleptic properties. However, lupin presents anti-nutrients and has a strong odor, generally described as green, grassy and sulfurous. Fermentation could modify some of those characteristics making lupin flour more suitable for the breadmaking process. The proposal of this research was to study the nutritional, rheological and physical properties of breads, when conventional wheat flour was replaced by whole lupin flour (LF) or type IV lupin sourdough (LS) at 10% and 30%. The proximate composition was determined, to validate the nourishing value of this flour. Further data showed that lupin flour addition delivered phytates in breads, increasing the concentration of these antinutrients. However, they were reduced by sourdough fermentation. MicrodoughLAB assessment revealed that LS substitution increased the water absorption and reduced the stability of doughs in all the samples. About physical characteristics of breads, redness (a*) and yellowness (b*) increased by adding LF and LS. The 30% LS substitution led to a specific volume reduction, hardness increasing and lower value of resilience. Nevertheless, LS and LF did not affect crumb porosity. Finally, the determination of volatile compounds showed a significant influence of the addition of LF or LS in the odor profile of lupin-fortified bread. LF and LS could stand as candidates for legume-based supplementation in bakery products, granting nutritional and sensory enhancement value mostly when natural fermentation is implemented. Moreover, future studies could be fruitful for deepening understanding about rheological and functional challenges