OPTIMIZATION OF CONTROLLED GERMINATION TIME AND TEMPERATURE FOR PAJURO SEEDS (Erythrina edulis) TO INCREASE BIOACTIVE COMPOUND CONTENT AND ANTIOXIDANT POTENTIAL

Germination is a bioprocessing technique that improves the nutritional, biological, and functional properties of seeds by promoting the synthesis of readily assimilable antioxidant bioactive compounds. Pajuro (Erythrina edulis) is a protein-rich Andean legume with potential for the development of functional foods. This study aimed to optimize the germination time (X₁: 24–96 h) and temperature (X₂: 16–32 °C) of pajuro seeds using a 2² rotatable central composite design and response surface methodology. The objectives were to maximize the contents of gamma-aminobutyric acid (GABA), total soluble phenolic compounds (TSPC), and flavonoids, as well as antioxidant potential (ORAC), while minimizing proanthocyanidin and phytic acid contents in the flours (p < 0.10; R² > 0.80). The desirability function identified 96 h at 31.45 °C as the optimal germination conditions, with an overall desirability of 85.86%. Among the treatments evaluated, germination increased GABA from 123.36 to 297.82 mg/100 g (141%), TSPC from 625.79 to 1209.01 mg GAE/100 g (93%), flavonoids from 61.72 to 81.62 mg QE/100 g (32%), and ORAC antioxidant potential from 460.91 to 521.30 µmol TE/100 g (13%), compared with the ungerminated control. Phytic acid content decreased from 40.58 to 6.47 mg EFS/100 g (84%). Proanthocyanidin content also decreased, from 202.92 to 29.67 mg CE/100 g (85%), potentially owing to their hydrolysis and the formation of soluble phenolic compounds. Analysis of variance showed that temperature had a greater influence on GABA and flavonoid contents, potentially through temperature-dependent activation of glutamate decarboxylase. Germination time was more influential for TSPC, antioxidant potential, and phytic acid reduction, consistent with cumulative phenolic biosynthesis and phytase activation. These findings show that controlled germination can produce whole pajuro flour with greater functional potential and lower levels of antinutritional factors, offering a viable option for developing healthier foods and adding value to Peruvian agrobiodiversity.

Funding: This work was funded by CONCYTEC through the PROCIENCIA program, within the framework of the Financial Scheme E041-2025-02 titled “Proyectos de Investigación Aplicada” (Grant PE501096410-2025). Thanks to CNPq for the research scholarship provided to M.S. (312759/2025-8).