Response of postharvest quality attributes and cultivars to greenhouse microclimate and storage conditions

Tomato postharvest quality management is important to limit losses that occur due to deterioration between harvest and consumption. This study investigated the effects of greenhouse microclimate and postharvest storage conditions on the postharvest quality attributes of four tomato cultivars. Tomato cultivars ('Bona', 'Star 9037', 'Star 9009' and 'Zeal') grown in a fan-pad evaporatively-cooled (FPVT) and an open-ended naturally-ventilated tunnel (NVT) were harvested at the mature-green stage. The tomatoes were placed under cold storage for 28 days at 13 degrees C and RH of 85%, and under ambient air conditions at 23 +/- 2 degrees C and RH of 52 +/- 4%. The tomato samples were measured for firmness, color, pH and total soluble solids (TSS) and triplicated data analyzed by ANOVA using MSTATC. The greenhouse microclimates and storage conditions significantly (P=0.05) influenced firmness, color, TSS content and pH values of the four tomato cultivars. The NVT-grown tomatoes had a higher (by 7.4%) firmness which was retained for a longer period and an overall 10.3% higher TSS content during storage for all the cultivars. The cultivar 'Bona' had the least firmness (21.5% lower than the firmest cultivar, 'Star 9009') and the highest TSS content (up to 8.3% higher) and the lowest pH, with 3.64, up to 5.0% lower than the other cultivars. Furthermore, 'Bona' tomatoes had the lowest L* (by up to 17.5%) and hue angle (by up to 20.9%) and thus, ripened and deteriorated faster than the other cultivars. The interaction effect between microclimate, cultivar and storage conditions for tomatoes grown in the NVT led to 14.9 and 22.7% higher firmness for 'Bona' and 'Zeal', respectively. TSS content for the NVT-grown tomatoes was 20.0 to 26.2% higher under ambient conditions than cold storage conditions for all cultivars. Changes in color of FPVT-grown 'Bona' and NVT-grown 'Zeal' were slower under cold storage conditions. 'Star 9009' and 'Star 9037' were the least affected by the interaction effects, retaining higher firmness with the least color changes, although they had lower TSS and higher pH values. This study showed that NVT-grown tomatoes ripened faster and retained better textural qualities. The cold storage conditions had increasing effect on firmness and decreasing effect on ripening.