Effect of Soaking Temperature on the Changes in Composition of Bioactive Compounds in Sprouted Quinoa Seeds (Chenopodium quinoa Willd.): Online First: 11/11/2026

Germination is a simple bioprocess that can improve the functional value of quinoa, but the effect of pre-germination soaking temperature on the variation in bioactive compounds remains unclear. This study evaluated the effects of soaking temperature (25, 30, and 35 °C for 4 h) followed by 24 h dark germination on germination percentage, γ-aminobutyric acid (GABA), total saponin content, and DPPH radical-scavenging activity of Cahuil quinoa (Chenopodium quinoa Willd.) seeds. Experiments were conducted in three independent replicates. Soaking at 30 °C produced the highest germination percentage (33.53 ± 1.40%), significantly exceeding those obtained at 25 °C (30.30 ± 2.00%) and 35 °C (30.90 ± 1.70%) (p < 0.05). In contrast, GABA increased markedly with soaking temperature and reached 2.44 ± 0.11 mg/g at 35 °C, compared with 0.93 ± 0.04 and 1.06 ± 0.05 mg/g at 25 and 30 °C, respectively. Total saponin content was not significantly affected by soaking temperature and ranged from 29.73 ± 3.05 to 31.78 ± 4.33 mg/g. DPPH radical-scavenging activity was highest after soaking at 35 °C (9.76 ± 0.37 μmol TE/g DM), followed by 25 °C (8.61 ± 0.14 μmol TE/g DM), and was lowest at 30 °C (6.31 ± 0.03 μmol TE/g DM). These results indicate that, among the tested temperatures, 35 °C is the most suitable soaking temperature for promoting GABA accumulation and antioxidant activity in quinoa seeds.