Effects of different soaking and germinating conditions on γ-aminobutyric acid, antioxidant activity, and chemical composition of djulis (Chenopodium formosanum)

• Published in: Journal of agriculture and food research 2024-09, Vol.17, p.101162, Article 101162
• Main Authors: Lu, Wen-Chien, Cheng, Yu-Tsung, Chan, Yung-Jia, Yan, Jin, Li, Po-Hsien
• Format: Article
• Language: English
• Subjects: Antioxidant; Chenopodium formosanum; Germination; Soaking; γ-aminobutyric acid
• ISSN: 2666-1543; 2666-1543
• DOI: 10.1016/j.jafr.2024.101162

Djulis (Chenopodium formosanum), a native plant of Taiwan, is esteemed for its rich nutritional profile, encompassing high levels of dietary fiber, proteins, essential amino acids, and microelements. This study delved into the influence of soaking and germinating conditions on the synthesis of γ-aminobutyric acid (GABA), total phenolic content (TPC), antioxidant activity, and enzymatic activity in djulis. Enrichment culture tests were conducted to ascertain optimal soaking conditions. Results revealed that soaking djulis seeds for 4 h at 25 °C before germination notably augmented GABA production. Furthermore, djulis seeds subjected to soaking and germination at 30 °C for 48 h exhibited heightened GABA and anthocyanin contents. Conversely, germination at 25 °C for 48 h demonstrated superior TPC and 2,2-diphenylpicrylhydrazyl (DPPH) free radical scavenging activity. Optimal concentrations of glutamic acid, monosodium glutamate, pyridoxal-5′-phosphate (vitamin B6), Ca2+, and pH were found to enhance glutamine acid decarboxylase activity, consequently elevating GABA content. In summary, fine-tuning soaking and germinating conditions presents a promising avenue for augmenting GABA production in djulis, thereby bolstering its nutritional and functional utility. Future investigations aimed at elucidating the molecular mechanisms underlying enzymatic activity modulation during soaking and germination could yield valuable insights into optimizing GABA production. [Display omitted] •Soaking djulis seeds before germination significantly improved GABA production.•Germination conditions of the djulis were optimized to increase the content of GABA, polyphenols, and antioxidant capacity.•Appropriate supplementation of the soaking solution increased the GAD activity and GABA content.