Shelf life and storage stability of cold plasma treated kiwifruit juice: kinetic models

This study examined the quality changes and shelf life of cold plasma (Cold plasma-optimized, S2: 30 kV/5 mm/6.7 min and Cold plasma-extreme, S3: 30 kV/2 mm/10 min) and thermally-treated (S4: 90°C/5 min) kiwifruit juice packed in glass and polyethylene terephthalate bottles stored at 5, 15, and 25°C. Cold plasma and thermally treated juice samples were analyzed for peroxidase activity, microbial enumeration, bioactive compounds degradation, and sensory quality for up to 120 days. The residual activity of peroxidase enzyme in S2 sample after cold plasma treatment was 23.85%, decreasing with increase in storage time and temperature. After cold plasma and thermal treatment, the aerobic mesophiles and yeasts and molds count were below detectable limits in kiwifruit juice. Aerobic mesophiles and yeasts & molds emerged in S2, S3, and S4 samples stored at 5°C after 70, 70, and 90 days, respectively. The total color change increased with increase in storage time and temperature, whereas ascorbic acid, total phenolic content, total antioxidant capacity, and overall acceptability decreased. The shelf life of S2 in glass bottles was 100, 80, and 60 days at 5, 15, and 25°C based on total color change ≥ 12, ascorbic acid loss ≥ 50%, microbial count ≥ 6 Log CFU/mL, or overall acceptability < 5. Quality indices, including total color change, overall sensory acceptability, and ascorbic acid, were modeled, and zero-order model performed better than first and second-order reaction models. Furthermore, Arrhenius, Eyring, and Ball models were employed to model temperature-dependent reaction rates, and the Ball model performed better. So, the zero-order reaction and Ball model were combined to predict kiwifruit juice’s shelf life.