4. Conclusion
The relative contents (RC) of lutein, β-carotene, vitamin C, total phenolic
compounds and relative antioxidant capacity (RAC) of broccoli
juice treated by HIPEF were significantly influenced by electric field
strength, treatment time and polarity mode. HIPEF treatments applied
in bipolar mode led to higher relative contents of lutein, β-carotene,
total phenolic and RAC than those applied in monopolar mode. In contrast,
RC of vitamin C was greater when broccoli juice was treated by
HIPEF in monopolar mode in comparison with bipolar mode. The RC
of carotenoids (lutein and β-carotene) augmented when the broccoli
juice was HIPEF-processed at the strongest conditions (35 kV/cm for
2000 μs in bipolar mode). The results demonstrated that the bioactive
compounds of broccoli juice were better retained by HIPEF processing
as compared with that treated by heat. Therefore, HIPEF technology
could be considered as a good alternative to preserve the antioxidant
characteristics of broccoli juice. Further research focused on the mechanistic
insight of the changes in bioactive compounds during HIPEF
processing of foods is required.