409 Dynamic CA-Storage for the Quality Assurance of Pepino (Solanum Muricatum Ait.) H. Prono-Widayat, S. Huyskens-Keil and P. Lüdders Institute for Horticultural Science, Section Postharvest Quality and Department of Fruit Science, Humboldt University Berlin, Königin-Luise-Str. 22, D-14195 Berlin, Germany M. Schreiner and P. Peters Institute for Vegetable and Ornamental Plants Großbeeren/Erfurt e.V., Theodor- Echtermeyer-Weg 1, D-14979 Großbeeren Germany Keywords: controlled atmosphere storage, ripening, color, firmness, carbohydrate, Solanum muricatum Abstract Mature and ripe pepinos (Solanum muricatum Ait.) were stored under different dynamic CA storage conditions (DCA) at either 5°C or 10°C (RH 95%) for up to 21 days. One group of mature fruit and two groups of ripe fruit (6 fruit per treatment) were stored under a DCA with 5% O 2 and 15% CO 2 (DCAI) for mature fruit and 5% O 2 and 20% CO 2 (DCAII) for ripe fruit for the first two days of storage. For another 19 days, O 2 and CO 2 concentrations were each kept constant at 5%. One group of ripe pepinos was stored under another DCA with 5% O 2 and 20% CO 2 for 7 days and 5% O 2 and 5% CO 2 for another 7 days (DCAIII). A control group of mature and ripe pepinos was stored separately at 5°C in air for up to 21 days. Mature fruit showed lower chroma, higher skin firmness, and higher disaccharide/monosaccharide ratio than ripe fruit. Storing mature pepino fruit under DCAI resulted in a retention of fruit color (chroma), a higher skin firmness, and a higher disaccharide/monosaccharide ratio compared with the fruit stored without CA (5°C). Ripe fruit stored under DCAII and DCAIII also showed a lower decrease in chroma and in skin firmness, and a higher carbohydrate ratio after 21 days of storage compared with those in air. The different DCA treatments did not significantly affect the quality attributes of ripe pepinos. A storage life of three weeks can be recommended for ripe fruit stored under DCA. INTRODUCTION In USA, Europe and Japan the demand for pepino (Solanum muricatum Ait.) is increasing due to its nutritional value, flavor, and attractive appearance (National Research Council, 1989; Pluda et al., 1993). Since pepino is highly perishable, harvest is carried out at an early ripening stage, so the fruit can be transported a long distance with lower losses (Prono-Widayat et al., 2000). However, they often fail to ripen normally after arriving at the designated markets resultig in poor external and sensory quality with a short shelf life. Pepino is sensitive to chilling injury when fruit are stored at 5°C or below. A storage temperature of 10°C appears to be satisfactory (Harman and Beever, 1984; Ahumada and Cantwell, 1996). The advantages of controlled atmosphere (CA) in maintaining good external and internal quality of perishable fruit during storage and transport are well documented. This technique also offers the advantage that fruit might be harvested at a more developed ripening stage with much better quality while transporting them in CA-containers by ship. There have been limited studies about quality changes, postharvest physiology, and storage performance of pepino fruit stored under CA conditions. The objective of this research was to study the effects of different dynamic CA conditions and storage temperatures on the postharvest external and internal quality characteristics of pepinos. In this study, different gas compositions during storage were evaluated for their suitability in Proc. 8 th Int. CA Conference Eds. J. Oosterhaven & H.W. Peppelenbos Acta Hort 600, ISHS 2003