Inactivation efficacy of atmospheric glow discharge plasma against Zygosaccharomyces rouxii vegetative cells in apple juice and its impact on juice quality.

چکیده اصلی

Zygosaccharomyces rouxii dominates spoilage in concentrated and reconstituted apple juice. Its osmotolerance and biofilm-forming capacity hinder traditional juice sterilization. This work investigated atmospheric glow discharge plasma (GDP) inactivation of Z. rouxii vegetative cells in reconstituted apple juice prepared from commercial concentrate and corresponding juice quality changes. Experiments varied discharge powers, treatment durations and working gas types. Inactivation mechanisms were explored through reactive oxygen and nitrogen species and cellular damage. Juice quality attributes including physicochemical properties and nutritional contents were assessed before and after treatment. Both wild strains tolerated GDP better than the culture collection reference strain. Treatment with 350 W air-GDP for 50 s fully eliminated a ∼ 7.2 log₁₀CFU/mL three-strain cocktail. Air-GDP produced more microbicidal ozone and nitrite than nitrogen-GDP. GDP-generated reactive species were associated with cell membrane peroxidation, structural disruption and cytoplasmic leakage, which are probably the primary drivers of Z. rouxii inactivation. GDP treatment preserved juice nutrients and flavor, and minor shifts in pH, acidity, and color stayed within commercial standards. This work supports industrial plasma decontamination for fruit juice. Limitations mainly include laboratory-scale tests, exclusive vegetative cell assays, and narrow strain coverage. Further pilot trials and ascospore testing are required for full industrial translation.

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