Impact of Ionizing Radiation and Thermal Treatments on Furan Levels in Fruit Juice

The formation of furan in freshly prepared apple and orange juices as affected by ionizing radiation and thermal treatments was studied using a newly developed solidphase microextraction method coupled with gas chromatography-mass spectrometry (GC-MS). Results show that furan levels increased linearly as radiation dose increased from 0 to 5 kGy. Irradiation induced more furan in apple juice than in orange juice. During post-irradiation storage at 4 °C, furan levels increased in both apple and orange juices, particularly in the 1st 3 d. On the other hand, irradiation degraded deuterated furan (d4-furan) spiked in water and fruit juices. The rate of degradation as a function of radiation dose was the highest in water and the lowest in orange juice. Submerging the juice samples in boiling water for 5 min induced higher amounts of furan in orange juice than in apple juice, but autoclaving (121 °C, 25 min) resulted in more furan formation in apple juice than in orange juice. Results reported here suggest that both ionizing radiation and thermal treatments induce furan formation in fruit juices.