METABOLOMIC AND MICROBIAL PROFILING OF TROPICAL/SUBTROPICAL FRUITS AND SMALL FRUITS FOR QUALITY FACTORS AND MICROBIAL STABILITY
Location: Citrus and Other Subtropical Products Research
Title: Evaluation of the impact of hot water treatment on the sensory quality of fresh tomatoes
Submitted to: Acta Horticulturae
Publication Type: Proceedings
Publication Acceptance Date: May 1, 2011
Publication Date: January 1, 2012
Citation: Loayza, F.E., Brecht, J.K., Plotto, A., Baldwin, E.A., Bai, J. 2012. Evaluation of the impact of hot water treatment on the sensory quality of fresh tomatoes. Acta Horticulturae. 934:1305-1311.
Interpretive Summary: Flavor, firmness, nutrition and decay resistance are important characteristics for tomatoes, one of the major vegetable products in the US consumer diet, and a major crop in acreage and economic value. Hot water treatment had been shown to impart decay resistance in tomatoes, is theorized to enhance antioxidants for nutritional benefit, but it is not known what effect hot water treatments would have on tomato flavor. This study looks to answer this question using two tomato varieties; a newly released cultivar, ‘Tasti-Lee’ and one that is widely grown in Florida, ‘Florida 47’. Results showed that the hot water treatment of 52 or 52 ºC for 2.5 – 5 minutes did not have much effect on flavor. The most differences, however, were between the two varieties, with ‘Tasti-Lee’ having more overall flavor and ‘Florida 47’ being firmer andmore sour.
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 52, or 54 °C for 5.0, or 2.5 min, respectively. The fruit were then exposed to 100 µl/l 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 18 ± 1 °C and 80% relative humidity until fully ripened (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 tomato, fruity, vine/sharp aroma and flavor, but also musty and mealy. 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.