Effect of Controlled Atmosphere Storage Conditions on the Chemical Composition of Super Hardy Kiwifruit

Super hardy kiwifruit [<i>Actinidia kolomikta</i> (Maxim. & Rupr.) Maxim.] accumulate large amounts of biologically active compounds, but it is possible to store ripe fruit for a very short time, only 2 weeks at 0–5 °C. Therefore, it is necessary to determine optimal storage conditions to prolong fruit storage time. The aim of this research was to analyse changes in the basic chemical composition of fruit during ripening in controlled atmosphere chambers. Fruit was stored for 6 weeks at a constant temperature (0 °C) and humidity (90%) in different air compositions (No. 1—21% O₂, 78% N₂; No. 2—0.5% O₂, 98.5% N₂, 1% CO₂; No. 3—1.5% O₂, 95.5% N₂, 3% CO₂; No. 4—2% O₂, 93% N₂, 5% CO₂). The chemical composition of the fruit was determined at harvest, after 2, 4 and 6 weeks of storage. Dry matter, soluble solids, ascorbic acid, total chlorophyll and carotenoid contents were analysed. The greatest increase in the contents of dry matter and soluble solids after 6 weeks of storage was found in the chamber where O₂ was 2% and CO₂ was 5%. The ascorbic acid content decreased during the fruit ripening process regardless of the air composition. Most of the ascorbic acid remained in fruit stored in the chamber with 1.5% O₂ and 3% CO₂. The concentration of total chlorophyll and total carotenoids in the fruit increased as development progressed. The different air parameters in the storage chambers had different effects on the synthesis of pigments in fruit, but the content of pigments increased most in fruit stored in the chamber with atmospheric parameters 0.5% O₂ + 1% CO₂.