The adsorption of ochratoxin A in grape juice by Fe₃O₄-MIL-101 and its quality influences

The traditional physical detoxification method of ochratoxin A（OTA） has problems such as low efficiency and poor selectivity of adsorption materials, making it difficult to meet practical needs. Metal-Organic Frameworks（MOFs） materials exhibit better adsorption performance due to their high specific surface area and adjustable pore structure. In this study, Fe₃O₄-MIL-101 was prepared by loading a magnetic shell onto the MIL-101. The adsorption effect of Fe₃O₄-MIL-101 on OTA in grape juice and its effects on quality were studied. The results showed that when the molar ratio of the precursor H₂BDC, Fe₃O₄ and FeCl₃·6H₂O was 7∶ 1∶ 14, the adsorption effect of the material was the best. Under the optimal conditions, when the dosage of Fe₃O₄-MIL-101 was 8 mg, the initial mass concentration of OTA was 40 ng/mL, and the degradation rate of OTA reached 80.6% after reacting for 30 min at 25 ℃. After three cyclic experiments, the adsorption rate of this material for OTA remained at 66%. There were no significant changes in the contents of total acid, reducing sugar, Vitamin C, and soluble solids in the grape juice, while the absorbance and pH value decreased slightly. Despite some loss of reducing sugars and polyphenols, the overall nutritional quality of grape juice was still well preserved.