The multi-carboxyl metal-organic framework MIL-101(Fe) effectively adsorbs total purines from whole soybean seeds

Soybean is a nutritionally important crop, but its high purine content poses health risks for hyperuricemic people. We report a strategy for adsorbing purines directly from intact soybean seeds under mild conditions using the multi-carboxyl metal-organic framework MIL-101(Fe) with CaCl₂ solution, achieving an average adsorption rate of >50 % at 30 °C. Characterization confirmed the structural stability of MIL-101(Fe) and that hydrogen bonding and coordination interactions facilitated purine adsorption. Efficient adsorption by food-grade fumaric acid suggested that multi-carboxyl materials are suitable for purine adsorption. Soybean seeds in which the seedcoat formed a spongy porous structure during treatment exhibited significantly greater purine removal than those with a smooth structure. In the low-purine variety MMN, the method reduced purine content from 90.58 to 47.46 mg/100 g, meeting the ultra-low purine food standard (<50 mg/100 g). This work will enable efficient production of low-purine raw soybean, supporting the development of healthy products for hyperuricemic people.