Replacing wheat flour with debittered and fermented lupin in bread affects its physical and nutritional features. Lupin weakens the dough but improves protein, fat, and fiber content in the bread. Higher lupin substitution reduces bread volume and changes its texture, but fermented lupin lessens these effects. However, breads with fermented lupin may have a slightly acidic taste. Overall, using debittered and fermented lupin can enhance wheat bread's nutritional value, although breads with fermented lupin have better technological properties.