Combined effect of UV–C and passive modified atmosphere packaging to preserve the physicochemical and bioactive quality of fresh figs during storage

Abstract

Figs are an important constituent of the Mediterranean diet, widely consumed fresh. Due to their very short shelf life, postharvest techniques to preserve quality and safety should be implemented. The current work aimed to study the combined effect of a postharvest UV–C treatment (5 or 10 kJ m−2) followed by packaging under passive modified atmosphere (MAP) on physicochemical and bioactive quality of fresh figs (cv. ‘Colar’) stored up to 12 d at 0 ºC (90–95% RH). As controls, UV–C untreated and air-stored (AIR) samples were used. The flesh firmness, skin colour, soluble solids content (SSC), titratable acidity (TA), pH, total phenolic content and total antioxidant activity were monitored. The steady-state modified atmosphere reached since day 8 was 17 kPa CO2 and 4 kPa O2. UV-C treated samples did not show visual decay incidence, while mycelial growth was observed in untreated figs on day 12. Figs treated with 10 kJ m-2 UV–C and stored under MAP conditions showed the highest flesh firmness with values of 0.6 N, which is 50% higher than in AIR. Skin darkening observed among samples was higher in 10 kJ m-2 with Chroma decreases of 2.6 units on day 12 under MAP, although panellists preferred this treatment according to its visual appearance. Higher SSC and TA differences were found in UVC-treated samples during storage. Moreover, 10 kJ m-2 UV–C and MAP induced the highest total phenolic content accumulation, with 260% and 540% higher values from day 4 to day 12 for skin and flesh, respectively. In conclusion, a 10 kJ m−2 UV–C treatment after harvesting followed by packaging under MAP conditions may be considered a good tool to preserve the physicochemical and bioactive quality of fresh figs during 12 d at 0 ºC.