Effects of Exogenous Selenium on Accumulations of Selenium, GABA and Antioxidant Activity of Chestnut During Germination

To investigated the effect of exogenous selenium on selenium enrichment and antioxidant activity of germinated chestnut. We treated ‘Zaofeng’ chestnuts with 0, 20, 40, 60 and 80 mg/L concentration of Na₂SeO₃, and the analyses focused on total Se, SeCys₂, MeSecys, Se^IV, SeMet, Se^VI, γ -aminobutyric acid (GABA), antioxidant enzyme (PAL, SOD, GPX, CAT) activity, non-enzymatic antioxidant substances (total polyphenols and flavonoids) content and antioxidant capacity (DPPH, ABTS) during germination. The results indicated that low concentration of selenium (20-40 mg/L) significantly promoted the organic transformation of selenium, increased antioxidant enzyme activity and phenol accumulation, and enhanced antioxidant capacity of chestnut. High concentration of selenium (80 mg/L) induced oxidative stress, inhibited enzyme activity and reduces antioxidant capacity of chestnut. During the germination of chestnut, selenite was absorbed by embryo and subsequently transformed into organic Se in vivo, ultimately being stored in the form of SeCys₂. The selenium enrichment rate decreased significantly with the increase of Na₂SeO₃ treatment concentration. Furthermore, the treatment with 40 mg/L Na₂SeO₃ led to a significant increase in GABA content of germinated chestnut. Overall, 20-40 mg/L Na₂SeO₃ were identified as the suitable concentration for germinated chestnut. This study provides a theoretical basis for developing functional food of selenium-enriched germinated chestnut.