Enhancing Microbial Safety and Nutritional Quality of Fresh Carrot Juice: Insights From Plasma Jet and Spark Plasma Discharge (SPD) Treatments

Abstract

Background

The food industry is gaining interest in nonthermal processing methods as an alternative to conventional pasteurization. In addition to preserving nutrition and sensory qualities, pulsed spark discharge (PSD) and plasma jet treatments have shown potential for microbial decontamination. In the current study, PSD treatment and plasma jet treatment are evaluated for their effectiveness in improving carrot juice’s microbial safety and quality.

Methods

Two different electrode configurations were used for PSD treatment of carrot juice samples, as well as plasma jet treatment of samples. Microbiological analyses were conducted to determine reductions in Bacillus cereus (B. cereus) spores, lactic acid bacteria, total aerobic bacteria, mold, coliforms, yeast, E. coli, and E. faecalis. A variety of nutritional parameters, including vitamin C, β-carotene, and sugar content, were analyzed, along with changes in color and phenolic content.

Results

PSD 1, PSD 2, and plasma jet treatment reduced B. cereus spores by 4, 3, and 0.7 log₁₀ (CFU/mL), respectively. During plasma jet treatment, all tested microbes were eliminated. After 6 min of PSD treatment, vitamin C remained stable but decreased with extended exposure. β-Carotene levels remained unchanged for 7 min and then declined after 9 min. Additionally, reductions in sugar content were observed after 7 and 9 min, while increases in total phenolic content were observed. Despite an increase in yellowness and a decrease in redness, lightness did not change.

Conclusion

PSD and plasma jet treatments significantly enhance carrot juice’s microbial safety while maintaining its nutritional and sensory properties. In addition to improved shelf life and consumer appeal, these alternatives may prove valuable in the juice industry.