Reuse of almond by-products: Scale-up production of functional almond skin added semolina sourdough breads

The present work reports the application of powdered almond skin (PAS) for industrial bread production. Three trials were conducted involving seven bread shapes, including control production (CTR), and two experimental productions with PAS addition [5–10 % (w/w), 5-PAS and 10-PAS, respectively]. Sourdough inoculum determined the acidification of all doughs and the levels of lactic acid bacteria increased. Spore-forming aerobic bacteria, members of the Enterobacteriaceae family, and total coliforms were not detected until the end of the fermentation process. PAS addition determined a lower weight loss, an increase of firmness, a diminution of specific volume, and a different sensory profile of the breads. Mafalda was the most appreciated bread shape and was subjected to photothermal aging. 10-PAS sample, after nine-day stress, still showed a significant total phenolic compound TPC content (111.0 mg GAE/g extract). The radical scavenging potential increased with PAS with a final IC50 of 103.3 μg/mL in 10-PAS breads. Experimental breads exhibited a notable enhancement in protection against lipid peroxidation. Mold-free shelf life assessment showed a 10-day shelf life for CTR breads, while a 12-day shelf life in presence of PAS. Collectively, the data suggest that PAS holds significant promise as a functional additive for industrial production of bread.