Quality of green (Actinidia chinensisvar.deliciosa‘Hayward’) and yellow (A. chinensisvar.chinensis‘Soreli’) kiwifruit during cold storage at 0°C in normal atmosphere and with gaseous ozone

Abstract

Fruit and vegetables are commonly stored in refrigerated rooms and, often, for medium/long periods, in pre-defined gaseous atmospheres (CA: different combinations of N2, O2, CO2). In this study, green and yellow kiwifruits were stored at 0°C with normal atmosphere (CK) or with an atmosphere enriched with O3 (150 ppb during the day and 180 ppb during the night), for 42 days. Subsequently the fruits were placed in shelf-life conditions for 10 days. From the beginning (T0), fruits were sampled six times during the 42 days of storage, and four more times thereafter, every 3‑4 days during 10 days of shelf life. Chemical and physical analyses of total soluble solid content (SSC), titratable acidity, color, changes of firmness and total chlorophylls and carotenoids content were performed. In addition, microbial analysis was carried out. Green kiwifruits were harvested at an earlier stage than yellow kiwifruits (6.5 vs 8.0 °Brix); firmness was 3.5 and 2.5 N mm-1 for green and yellow kiwifruits, respectively. Ozone treatment maintains higher firmness retention and lower SSC in 'Hayward' kiwifruit during cold storage and shelf life and does not negatively influence it in 'Soreli'. Color analysis (color difference, ΔE) in yellow and green kiwi samples was higher in ozone-treated fruits during cold storage at 0°C and shelf-life conditions. The microbiological data showed no significant variation between cultivars or treatments. Overall, treatment using continuous gaseous ozone can be a suitable choice for the preservation of 'Hayward' and 'Soreli' kiwifruits.