Pre-Treatment Effects on Chemico-Physical Characteristics of Argan Press Cake Used for Bread Production

Argan oil is known worldwide for its nutritional, therapeutic, and cosmetic benefits. However, the extraction process produces 40–50% of argan press cake (APC), which is rich in protein, fiber, and minerals. Despite its nutritional potential, the high saponin content of APC imparts a bitter taste and anti-nutritional properties, making it unsuitable for human consumption and often wasted. This study addresses this issue by using boiling treatments with citric acid (CA) and distilled water (DW) to reduce the saponin content while evaluating the impact on APC quality. In addition, this study explores, for the first time, the incorporation of treated argan press cake, APC-CA and APC-DW, at different levels (5%, 10%, 15%, and 20%) into whole wheat flour (WWF) for bread production to improve the nutritional profile. The results indicate that both treatments significantly reduce saponin content while maintaining nutritional quality comparable to untreated APC. This includes a 50% reduction in phytic acid levels. The absence of tryptophan fluorescence emission was observed in APC-CA, which may be related to chemical degradation or interactions with other molecules. The substitution of APC-CA and APC-DW increased the protein of composite flours in a level-dependent manner. At substitution levels up to 10%, APC-CA and APC-DW positively influenced the technological properties of the bread. This study demonstrates the potential of APC to improve the nutritional value of bread and supports zero-waste initiatives by reusing by-products.