Impact of Pretreatment with Dielectric Barrier Discharge Plasma on the Drying Characteristics and Bioactive Compounds of Jackfruit Slices

Background

Hot air drying is a popular method for preserving the production of jackfruits, but heat treatment damages their nutritional qualities. Cold plasma is one of the pretreatment methods to prevent quality attributes of fruits before drying. In the present work, we studied the effect of dielectric barrier discharge (DBD) plasma on the drying characteristics, microstructure, and bioactive compounds of jackfruit slices with different pretreatment times (15, 30, 45, and 60 s), followed by hot air drying at 50, 60, and 70 °C. A homemade DBD device was operated via three neon transformers.

Results

Optical emission spectrophotometry revealed the emitted spectra of the reactive species in DBD plasma, including the N₂ second positive system, N₂ first negative system, nitrogen ion, and hydroxyl radical. The results showed that the DBD plasma promoted moisture transfer and enhanced the drying rate, related to the changes in the surface microstructure of samples damaged by DBD plasma. The modified Overhults model was recommended for describing the drying characteristics of jackfruit slices. The contents of ascorbic acid, total phenolics, total flavonoids, total polysaccharides, and antioxidant activity in pretreated jackfruit slices were improved by 9.64, 42.59, 25.77, 27.00, and 23.13%, respectively. However, the levels of color and carotenoids were reduced.

Conclusion

Thus, the bioactive compounds in dried jackfruit slices can be improved using the DBD plasma technique as a potential pretreatment method for the drying process.

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