Simultaneous Use of Various Pre-cooling Methods and Temperature Control During Transport on the Quality of Exported Tomatoes

Introduction
Fruits and vegetables are crucial horticultural products that significantly contribute to meeting human nutritional needs and health. Tomato is among the perishable products. Its waste plays a considerable role in the production and consumption cycle. Technologies for post-harvest management, along with suitable transportation and storage conditions, can help minimize the majority of its waste. By extending its shelf life and preserving its quality during transport, the product can be exported to far-off markets. Pre-cooling techniques and temperature management during storage and transportation are crucial for prolonging shelf life and reducing waste of products such as tomatoes.
Materials and Methods
In this study, the effect of pre-cooling methods, storage and transportation temperatures, and duration of storage time was investigated on the quality of tomato (Izmir cultivar). This is done to preserve product quality during transit to the market by ensuring the cold chain is maintained.  The methods used for pre-cooling included forced-air cooling and hydro-cooling, which were conducted at air and water temperatures of 8 °C. The temperatures for storage and transportation were set at 12 °C and 21 °C. Following the pre-cooling process, all samples were stored for 20 days, and their quality characteristics, such as firmness and color, were assessed every 5 days during the storage period. As a control treatment, some tomatoes were also stored under the same conditions as the pre-cooled samples. Firmness was evaluated through compression and puncture testing. The color indices of the samples, such as L, a, and b, which represent the levels of brightness, redness, and greenness, as well as yellow and blue in the samples, were determined using Photoshop software. The total color variation along with color density was computed. The analysis of the data was conducted employing a randomized complete block design across three replications.
Results and Discussion
The 7/8th cooling time of tomato using the forced-air cooling and hydro-cooling was 225 min and 128 min, respectively. The cooling rate is more rapid with hydro-cooling. Pre-cooling techniques, temperatures for storage and transportation, as well as storage duration, significantly affected the maximum compression force at a 1% probability level. The maximum compression force was achieved in the fruit cooled by the forced air cooling. The higher compression force indicates the higher firmness. The firmness of tomatoes, stored at 12 °C, was higher than that of those stored at 21 °C (28 %). Throughout the storage period, the firmness of the samples declined. The results showed that the desirable firmness was associated with the samples being pre-cooled through forced-air cooling, and stored at a temperature of 12 °C. Comparable results were achieved for puncture force. The puncture force of samples that were pre-cooled using forced air cooling and stored at 12 °C was greater than that of other samples. The methods of pre-cooling and the duration of storage significantly impacted the color density and total color variation. The color variations of pre-cooled samples were less than those of the control samples (without cooling). This suggested that pre-cooling might decrease the ripening rate of tomatoes. Delays in ripening allow for the export of tomatoes to distant markets.
Conclusion
The results showed that it was possible to attain extended shelf life and maintain product quality through the use of forced-air cooling. Furthermore, shipping the product at 12 °C resulted in improved quality and an extended shelf life. Consequently, tomatoes ought to be transported in refrigerated containers. It was concluded that the shelf life of tomatoes can be extended through forced-air cooling and by transporting them at 12 °C via refrigerated truck.
Acknowledgment
This study has been conducted as an interior research project of the University of Tabriz. The authors have appreciated the university vice chancellor of research for its financial resources.