# Impact of Iron (II) Chloride Treatment on the Physical and Metabolic Changes in Mungbean Sprouts

## TL;DR

Iron (II) chloride treatment changes the seed coat color of mungbean sprouts and increases isoflavone levels without affecting physical traits.

## Contribution

FeCl2 treatment enhances metabolic quality by boosting isoflavone biosynthesis in mungbean sprouts.

## Key findings

- FeCl2 treatment darkened the seed coat but did not alter physical traits of mungbean sprouts.
- Isoflavone aglycone levels, especially in seed coat and cotyledon, were significantly increased by FeCl2 treatment.
- The treatment enhances metabolic quality without compromising physical quality of sprouts.

## Abstract

Legume crops are rich in carbohydrates, proteins, and various secondary metabolites such as isoflavones. Micronutrient treatments regulate plant biological activities, including stomatal function, hormone balance, and antioxidant accumulation, thereby improving resistance to environmental stress. This study investigated the effect of FeCl2 treatment, which changed the seed coat color, on the physical and biochemical characteristics of mungbean sprouts. After 72 h of cultivation with FeCl2 (Fe–72 h), no significant differences in physical traits were observed compared with the control. However, the levels of isoflavone aglycones (daidzein, genistein, and glycitein) were significantly higher. These findings suggest that FeCl2 treatment does not affect the physical quality of mungbean sprouts but enhances their metabolic quality by catalyzing isoflavone biosynthesis, as these compounds function as iron chelators. Tissue‐specific analysis revealed that the seed coat and cotyledons accumulated the highest levels of isoflavone aglycones. The seed coat and cotyledons are directly exposed to FeCl2 during soaking, whereas newly developing tissues, such as the hypocotyl, are only indirectly affected. This difference in mineral exposure among tissues likely influences the biosynthesis of secondary metabolites. The observed increase in isoflavone content may improve stress resistance during mungbean cultivation and enhance the nutritional quality of mungbean sprouts as a health‐promoting food.

FeCl2 treatment darkened the seed coat color of mungbean sprouts without significantly affecting physical traits compared with the control (CK). In contrast, isoflavone aglycone contents were markedly increased, particularly in the seed coat and cotyledon. These results indicate that FeCl2 treatment enhances the metabolic quality of mungbean sprouts without compromising physical quality.