Proteomic Analysis of the Major Alkali-Soluble Inca Peanut (Plukenetia volubilis) Proteins

Sacha Inchi (<i>Plukenetia volubilis</i>) oil press-cake (SIPC) represents a new source of proteins of high biological value, with promissory food applications. However, knowledge of these proteins remains limited. In this study, a Sacha Inchi protein concentrate (SPC) was extracted from the SIPC, and proteomic analysis was performed to identify the major alkaline-soluble proteins. The electrophoretic profile highlighted the efficacy of alkaline pH and moderate temperature to extract the major proteins, from which a group of proteins, not previously reported, were registered. LC-MS/MS analyses produced abundant high-quality fragmentation spectra. Utilizing the Euphorbiaceae database (DB), 226 proteins were identified, with numerous well-assigned spectra remaining unidentified. PEAKS Studio v11.5 software generated 1819 high-quality de novo peptides. Data are available via ProteomeXchange with identifier PXD052665. Gene ontology (GO) classification allowed the identification of sequenced proteins associated with biological processes, molecular functions, and cellular components in the seed. Consequently, the principal alkali-soluble proteins from SPC were characterized through derived functional analysis, covering 24 seed-storage-, 27 defense-, and 12 carbohydrate- and lipid-metabolism-related proteins, crucial for human nutrition due to their sulfur-containing amino acids, antioxidant properties, and oil yields, respectively. This research makes a significant contribution to the current understanding of the Sacha Inchi proteome and offers valuable insights for its potential applications in the food industry.