EFFECT OF SURFACE COATING AND FILM PACKAGING ON THE KEEPING QUALITY OF SOLANACEOUS CROPS (Solanum muricatum Ait., Solanum quitoense Lam.)

In Europe the demand for exotic solanaceous fruit and vegetable crops, i.e. pepino dulce (Solanum muricatum Ait.) and naranjilla (Solanum quitoense Lam.) has significantly increased due to their high nutritional value, flavour and attractive appearance. These crops are exported mainly by seafreight, and often reveal a poor external and sensory quality with a short shelf life when arriving at the designated market. In the present study different postharvest treatments (surface coating, film wrapping) were evaluated in respect to their suitability to prevent quality loss and extend shelf life of the potential export crops pepino and naranjilla.
Fruits harvested at the color break stage were a) sprayed with sucrose ester coating, b) packed in a 250 g-PE-foodtainer sealed with polymeric film or c) wrapped with a biodegradable polysaccharide film. Thereafter, fruit were stored at simulated commercial storage temperatures of 5°C and 20° with 95% RH and 70-80% RH, respectively, for up to 21 days. Fruit were evaluated 7, 12 and 21 days after storage for their external appearance, i.e. color pattern and firmness, and internal quality attributes, such as total soluble solids, color pigments, storage- and cell wall carbohydrate constituents.
The results indicate that sucrose ester as a postharvest surface coating can prolong shelf life in pepino. However, it is less effective than the use of PE-foodtainer (for pepino) and biodegradable polysaccharide film (for naranjilla), which reduced fresh weight loss, transpiration rates and fruit softening. In pepino this coating also delayed ripening, as indicated by a higher retention of fruit color changes and inhibition of carotenoid synthesis.