ARS | Publication request: Evaluation of the impact of hot water treatment on the sensory quality of fresh tomatoes

Submitted to: International Horticultural Congress
Publication Type: Abstract Only
Publication Acceptance Date: January 15, 2010
Publication Date: N/A

Technical Abstract: Minimizing the effects of chilling injury during shelf-life is important for maintaining 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 2.5, 5.0, and 2.5 minutes, respectively. The fruit were then exposed to 100 µl/l ethylene for 2 days at 20 °C to uniformly initiate ripening, and any fruit not exhibiting external red color after the ethylene treatment were discarded. The remaining fruit were stored at 18 ± 1 °C and 80% relative humidity until fully ripe. Ripeness was evaluated by subjective firmness determination and colorimetry (CIE L*a*b* system), with the tomatoes judged to be ripe when the fruit were slightly soft and the a* value measured at the fruit equator exceeded 20. When selected as fully ripe, the color, firmness, concentration of sugars, organic acids, and volatile compounds were measured and a trained panel evaluated sensory quality using 18 descriptors measured on a 16-point scale. Sensory data were analyzed by several methods of multivariate analysis including principal component analysis (PCA), generalized Procrustes analysis, and agglomerative hierarchical clustering. PCA showed that Tasti Lee treated at 52 or 54 °C was associated with the most flavor descriptors, including tomato, fruity, vine/sharp aroma and flavor, but also musty and mealy. In contrast, Florida 47 treated at 25 or 54 °C were high on 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 a high score for green aroma.