Effect of Germination on Phenolic Compounds in Cañihua and Yellow Maize

Abstract

Germination induces biochemical changes in grains that can modify their phenolic composition through the release, transformation, and biosynthesis of phenolic compounds (Xu et al., 2020). Cañihua (Chenopodium pallidicaule Aellen) is an Andean pseudocereal recognized as a source of phenolic compounds and flavonoids (Peñarrieta et al., 2008). This study aimed to evaluate changes in total phenolic, total flavonoid, and proanthocyanidin contents associated with germination in cañihua and yellow maize (Zea mays L.). Cañihua was germinated at 20 °C for 72 h, whereas yellow maize was germinated at 25 °C for 72 h. Ungerminated and germinated samples were analyzed using spectrophotometric methods. Total phenolics were expressed as mg gallic acid equivalents per gram (mg GAE/g), while total flavonoids and proanthocyanidins were expressed as mg catechin equivalents per gram (mg CE/g). Each determination was performed using three technical readings from the same extract, and results are descriptively presented as mean ± standard deviation. In cañihua, total phenolics increased from 3.35 ± 0.30 to 6.80 ± 0.55 mg GAE/g, total flavonoids from 3.38 ± 0.21 to 4.79 ± 0.36 mg CE/g, and proanthocyanidins from 0.86 ± 0.03 to 1.58 ± 0.01 mg CE/g, representing increases of approximately 103%, 42%, and 85%, respectively. In yellow maize, total phenolics increased from 1.47 ± 0.05 to 2.43 ± 0.11 mg GAE/g, total flavonoids from 1.74 ± 0.09 to 3.26 ± 0.09 mg CE/g, and proanthocyanidins from 1.37 ± 0.06 to 1.56 ± 0.05 mg CE/g, corresponding to increases of approximately 65%, 88%, and 14%, respectively. The increase observed in cañihua is consistent with Abderrahim et al. (2012), who reported increased phenolic compounds during cañihua germination, with maximum responses at 72 h. More broadly, germination-related increases in phenolic compounds have been associated with metabolic transformations, including the release of bound phenolics and changes in phenolic biosynthesis (Xu et al., 2020; Günal-Köroğlu et al., 2025). The different magnitudes observed between cañihua and yellow maize may therefore reflect matrix-dependent responses to germination. Overall, under the evaluated conditions, germination was associated with higher phenolic compound contents in both grains, with the greatest relative increases observed for total phenolics in cañihua and total flavonoids in yellow maize.

Funding: This research was funded by the Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica (CONCYTEC) and the Programa Nacional de Investigación Científica y Estudios Avanzados (PROCIENCIA), under grant “E033-2023-01-BM Phase 2,” Contract No. PE501084298-2023-PROCIENCIA, and grant “E077-2023-01-BM,” Contract No. PE501094286-2024-PROCIENCIA