Synergistic effect of Cold Plasma and Ultra Sonication Treatments on the Shelf-Life and Storage Stability of Citrus reticulata Blanco

Nagpur oranges are well known for their pleasant flavour, high vitamin C content, and rich antioxidant compounds, which contribute significantly to human nutrition and health. However, their post-harvest shelf life is limited due to microbial spoilage, moisture loss, and physiological deterioration during storage. To address these issues, the present study investigated the effectiveness of non-thermal preservation techniques in extending the shelf life and maintaining the quality of Nagpur oranges. The fruits were treated with plasma activated water (PAW), ultra-sonication (US), and a combined treatment of PAW and US (PAW&US). After treatment, the fruits were packed using two different packaging materials, polyethylene terephthalate (PET) and corrugated fibreboard (CFB) boxes. The packaged fruits were stored under two storage conditions, ambient and cold storage, for a total period of 30 days. Quality evaluation was carried on 6 days of regular intervals to monitor storage changes. Physicochemical parameters such as total soluble solids (TSS), titratable acidity, and ascorbic acid content were analysed to determine fruit quality. Antioxidant activity was assessed using DPPH and ABTS radical scavenging assays. In addition, bioactive compounds including total phenolic content (TPC), total flavonoid content (TFC), and carotenoids were determined. Physiological parameters such as ethylene production and carbon dioxide evolution were measured to study respiration and ripening behaviour. The study aimed to identify the most suitable combination of non-thermal treatment, packaging material, and storage condition to maintain quality and extend the shelf life of Nagpur oranges.