Revalorization of the Residual Cake from Moringa Seeds as an Alternative Source of Plant-Based Proteins

The residual cake obtained after extracting oil from Moringa oleifera seeds is a promising source of plant-based proteins due to its high content of proteins, dietary fibre and essential minerals. However, its food applications are limited by a strong bitter taste that affects consumer acceptance and antinutritional compounds that reduce mineral bioavailability such as phytates. This study aimed to evaluate the effect of saline and ethanol treatments of moringa cake—reported in the literature as improving its sensory properties—on its nutritional profile. Proximal composition was determined by gravimetry for moisture, muffle incineration for ash, and solvent extraction with the Randall method for lipids. Protein content was analyzed using the Dumas combustion method. Mineral elements (calcium, iron, zinc, sodium) were quantified by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and phytates by High-Performance Liquid Chromatography (HPLC). The untreated cake revealed a favourable nutritional profile, mainly due to its protein content, but also contained high phytate levels. Both treatments slightly reduced phytates (5–12%), with saline extraction proving more effective. Nevertheless, mineral loss was observed, while there was a notable increase in sodium in the saline-treated samples. Ethanol treatment, in contrast, led to a statistically marked reduction in residual lipids. Importantly, both treatments diminished the bitter taste, improving sensory acceptability. Although neither method completely eliminated phytates, the overall improvements in protein quality, mineral profile, and sensory properties highlight the potential of moringa residual cake as a valuable ingredient. Thus, it emerges as a sustainable, high-nutritional-value source of plant proteins for the development of innovative food products.