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Assessment of thermosonication as postharvest treatment applied on whole tomato fruits: optimization and validation

Publication . Pinheiro, Joaquina; Ganhão, Rui; Gonçalves, Elsa M.; Silva, Cristina L. M.

Tomatoes are a popular and rich fruit due to their nutritional and bioactive composition as vitamins, antioxidants, and phenolics contributing to the promotion of consumer health. For this reason, emerging postharvest technologies need to be evaluated to achieve the maintenance of sensorial and quality-related characteristics, like color and texture, while aiding to fruit decontamination. Optimization of thermosonication as postharvest treatments on whole, mature-green tomatoes (cv. “Zinac”) to improve quality (color, texture, total phenolic content, and weight loss) was performed by response surface methodology. Temperature (32–48 °C), treatment time (13–47 min), and storage period at 10 °C (1–15 days) at constant ultrasound frequency (45 kHz; 80% power level), were the independent variables. In general, thermosonication delayed tomato color changes while achieving total phenolic content increase and good overall quality. Three optimal thermosonication conditions were selected and validated (32 °C-13 min, 35 °C-20 min and 40 °C-30 min). The most suitable thermosonication condition that promoted a longer storage while keeping a high-quality standard was at 40 °C during 30 min. This study demonstrated that thermosonication provides an effective alternative methodology to guarantee tomato quality without significant change during the expected postharvest period.

2019Journal article

Open access

Use of UV-C postharvest treatment for extending fresh whole tomato (Solanum lycopersicum, cv. Zinac) shelf-life

Publication . Pinheiro, Joaquina; Alegria, Carla; Abreu, Marta; Gonçalves, Elsa M.; Silva, Cristina L. M.

The effect of UV-C treatments (0.32, 0.97, 2.56, 4.16 and 4.83 kJ.m(-2) at 254 nm) on the physical-chemical properties [colour, texture, total phenolic content (TPC), weight loss (WL)], and mesophylic counts of whole tomato, was evaluated during 15 days at 10 A degrees C. During storage, the Ctr samples acquired faster red colour than all UV-C samples (higher a* and lower A degrees h values). Comparing texture of Ctr and UV-C samples at 15(th) storage day, an increase of 9 and 8 % on firmness of treated samples at low UV-C intensities (0.32 and 0.97 kJ.m(-2), respectively) was observed. At the end of the storage, Ctr samples showed ca. 4 Log(10) of mesophylic load, and the samples treated at 0.97 and 4.83 kJ.m(-2) revealed the lowest microbial load (1.9 and 3.2 Log(10), respectively). These results indicate that UV-C radiation, at an appropriate dose, combined with low storage temperature (10 A degrees C) are an effective method to preserve the postharvest life of tomato, without adversely affecting quality parameters.

2015Journal article

Restricted access

Postharvest quality of refrigerated tomato fruit (solanum lycopersicum, cv. zinac) at two maturity stages following heat treatment

Publication . Pinheiro, Joaquina; Alegria, Carla; Abreu, Marta; Sol, Manuela; Gonçalves, Elsa M.; Silva, Cristina L. M.

This study evaluated the effect of water heat treatment (WHT, immersion in a water bath at 40C - 30 min) application in alternative to the conventional decontamination treatment of chlorinated water (150 ppm at 5C, pH 6.5 during 2 min) on tomato (cv. Zinac) at two maturity stages (turning and pink). Physiochemical attributes, enzymatic activities and microbial load were evaluated after treatments and during 14 days of storage at 10C. The WHT applied was very effective on microbial reduction and delayed physiochemical changes of tomato, namely firmness loss and red color development during storage period, especially at turning maturity stage. Based on the firmness parameter, shelf-life of control and WHT samples were determined. Our results provide strong evidence that postharvest WHT (40C - 30 min) for tomato fruits at turning maturity stage guarantees the overall quality at 10C twice as long of fruits washed with chlorinated water.

2015Journal article

Restricted access

Tomate - Metodologias de preservação da qualidade do fruto inteiro

Publication . Pinheiro, Joaquina; Alegria, Carla; Abreu, Marta; Gonçalves, Elsa M.; Silva, Cristina L. M.

2012Journal article

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Kinetics of changes in the physical quality parameters of fresh tomato fruits (Solanum lycopersicum, cv ‘Zinac’) during storage

Publication . Pinheiro, Joaquina; Alegria, Carla; Abreu, Marta; Gonçalves, Elsa M.; Silva, Cristina L. M.

The effects of storage at different temperatures (2, 5, 10, 15, and 20 degrees C) conditions on whole tomato (Solanum lycopersicum, cv. 'Zinac', fruits harvested at mature-green stage) quality parameters, such as colour, chilling injury, firmness, weight loss and total phenolic content, were investigated during a month period. Storage at all temperatures had significant impact on the quality parameters analysed. Significant alterations in tomato green colour, firmness and weight loss were observed. The results also revealed a slight increase in the total phenolic content, and that refrigeration storage at 2 and 5 degrees C induced chilling injuries. A fractional conversion model fitted well the experimental data on colour parameters (a. and degrees h value), firmness and weight loss. The storage temperature effect was successfully described by the Arrhenius law. These results represent a good predictive tool for tomato quality estimation along the food chain.

2013Journal article

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