EVALUATION OF THE IMPACT OF HOT WATER TREATMENT ON THE SENSORY QUALITY OF FRESH TOMATOES

Minimizing the effects of chilling injury during shelf-life is important for main¬taining the sensory quality of fresh tomato fruit. Postharvest hot water treatments within certain limits of exposure time and water temperature have been shown to increase the resistance of tomatoes to chilling injury. Mature-green ‘Tasti-Lee’ and ‘Florida 47’ tomatoes were submerged in water at 25 (control), 52, or 54°C for 5.0, 5.0, or 2.5 min, respectively. The fruit were then exposed to 100 µl L^-1 ethylene for 2 days at 20°C to synchronize ripening, and any fruit not exhibiting external red color after the ethylene treatment were discarded. Fruit were stored at 20±1°C and 80% relative humidity until fully ripe (CIE a*>20). The color, firmness, sugars, organic acids, and volatile compounds were measured and sensory quality was evaluated by a trained panel with 18 descriptors on a 16-point scale. Sensory data were analyzed by principal component analysis (PCA), generalized procrustes analysis (GPA), and agglomerative hierarchical clustering (ACH). PCA analysis showed that ‘Tasti Lee’ treated at 52 or 54°C had the most flavor descriptors, including ‘overall tomato’, ‘fruity/floral’, ‘vine/sharp’ aroma and flavor, but also ‘earthy/musty’ and ‘mealiness’. In contrast, ‘Florida 47’ treated at 25 (control) or 54°C were high for ‘firmness’ and ‘sourness’ descriptors. ‘Florida 47’ treated at 52°C and ‘Tasti Lee’ treated at 25°C were in the middle of the first factor on the PCA plot, with ‘Florida 47’ having a high score for ‘salty’, and ‘Tasti Lee’ high score for ‘green’ aroma.