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Enhancing supply chain efficiency for air transport of horticultural products by simplified heat and mass transfer modelling
(2026-08-01)
Jantapirak, Suveena
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Duret, Steven
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Laguerre, Onrawee
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Denis, Alain
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Paviet Salomon, Yvanne
Maintaining temperature and quality stability of fresh horticultural products during air transportation is challenging due to highly variable thermal environments and limited airflow inside Unit Load Device (ULD) containers. This study developed a simplified three-dimensional heat and mass transfer model to predict product temperature and moisture evolution within a ULD container under realistic operating conditions. Plaster mangoes were used to avoid the variability of the real product properties. Convective heat transfer and three-directional thermal resistances were integrated into an unsteady heat balance model while the model parameters were calibrated using Monte Carlo simulation. A complementary mass transfer model, considering the ULD container as a closed moisture domain, was implemented to estimate product mass loss. Model performance was evaluated using cooling experiments under controlled conditions and field measurements in a ULD shipment from Bangkok to Paris by air transport. Simulated air and product temperatures showed good agreement with experimental data, with RMSE values below 3.5 °C. The model successfully captured the pronounced thermal load on top-layer boxes during tarmac exposure and the faster cooling of bottom boxes through conduction with the bottom wall during flight. Predicted mass loss (1.0-1.1%) also aligned with field data (1.1-1.2%). The model provides a practical tool for assessing the effects of operational and environmental conditions on fruit quality during air transport.
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Thermal performance evaluation of water-based gel packs and insulating covers: A case study on raw milk preservation for local transport
(2025-12-01)
Chaomuang, Nattawut
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Laguerre, Onrawee
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Flick, Denis
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Duret, Steven
Maintaining the quality and safety of raw milk during transportation to collection centers poses significant challenges for small-scale producers, especially in regions with limited access to advanced refrigeration systems. This study proposes a cost-effective cooling system utilizing water-based phase change material (PCM) gel packs and UV-reflective covers. The thermal performance was evaluated using a tank filled with water, both with and without PCM, under constant and variable ambient temperature conditions. Results demonstrated that the tanks with PCM achieved a temperature reduction of 10–13 °C within an hour. Comparative analysis revealed similar thermal behaviors for milk and water, enabling the extrapolation of results. A simplified heat transfer model based on energy balance was developed to predict product temperature changes under different operational conditions. Some input parameters were adjusted using experimental data, and the model was subsequently validated against separate experimental datasets, showing reasonable accuracy (RMSE < 3.0 °C). The model could be used for application under comparable conditions. Furthermore, milk quality preservation was assessed through the enumeration of Escherichia coli and total coliforms in milk stored in tanks with and without PCM, as well as through predictive microbiological modeling. Both measured and predicted results suggested a moderate reduction in E. coli growth rates (1.1–1.3 times slower) in the tank with PCM, depending on initial microbial load. Based on these findings, the proposed system offers an effective and economical solution for small milk producers, enhancing cold-chain management and reducing spoilage.
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Storage conditions, energy consumption, and food safety implications of domestic refrigerators in Bangkok
(2025-12-01)
Chaomuang, Nattawut
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Potisuwan, Cheeraphat
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Duret, Steven
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Derens-Bertheau, Evelyne
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Paviet-Salomon, Yvanne
Domestic refrigeration plays a critical role in food preservation and safety by maintaining optimal storage conditions for perishable items. This study investigated the temperature and humidity conditions, as well as the energy consumption, of domestic refrigerators in Bangkok. Data were collected through on-site investigations of 123 refrigerators using data loggers to record temperature, humidity, and electrical consumption over a five-day period. In addition, a predictive microbiological model was used to assess the potential for microbial growth under the investigated storage conditions, specifically of Listeria monocytogenes and lactic acid bacteria (LAB). Results indicated that although the overall mean temperatures of chilling compartments (5.0 ± 2.5 °C) were within the recommended range for domestic refrigeration, only about 30–40 % of individual refrigerators consistently maintained temperatures at or below 5 °C on the top and middle shelves throughout the five-day monitoring period, where fresh and ready-to-eat products are typically stored. Electrical consumption analysis revealed significant differences across refrigerator types; appliances with two doors and bottom freezers exhibited the highest annual electrical consumption, while single door refrigerators recorded the lowest. However, the specific energy consumption (SEC) did not differ significantly among refrigerator types. The microbial exposure assessment based on a test product highlighted that for over 50 % of refrigerators, L. monocytogenes load exceeds the regulation safety limits (> 102 CFU/g) within five days. These findings emphasize the need for improved temperature control, appliance design, and consumer education to ensure food safety and energy efficiency in domestic refrigeration.
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Thermochromic phase change beads based on phenolphthalein/ octadecylamine/ decanol for low-temperature indication and thermal buffering in cold chain logistics
(2025-07-01)
Thanaritthimanomai, Aunchisa
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Monvisade, Pathavuth
This study presents the development of thermochromic phase change beads (TC-BPA) designed for low-temperature applications (0–5 °C) in cold chain logistics. The beads were fabricated by encapsulating a ternary system—comprising phenolphthalein (PHP) as the color former, octadecylamine (ODA) as the developer, and decanol (10OH) as the solvent—within an alginate shell using a simple extrusion-dripping technique. Optimization of the component ratios yielded uniformly spherical beads (1.82–2.20 mm diameter) with rapid and reversible color transitions. Notably, the optimal formulation (TC-BPA10) shifted from purple to pale pink within 10 s (ΔE = 61.46 ± 1.27) and turned completely white within 60 s (ΔE = 82.66 ± 0.77) at 25 °C. Differential scanning calorimetry revealed a melting temperature of 4.9 °C and a latent heat of 200.05 J/g, with only a slight decrease after 100 thermal cycles. Additionally, TC-BPA10 maintained a stable temperature range (–2.2 °C to 2.9 °C) for approximately 28 min, demonstrating effective thermal buffering. These properties suggest that TC-BPA10 is a promising candidate for integrated temperature monitoring and energy storage in smart refrigerated packaging in cold chain logistics.
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Evaporative cooling with a wet fabric blanket for non-refrigerated horticultural produce transport: An experimental study
(2024-12-01)
Chaomuang, Nattawut
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Laguerre, Onrawee
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Supapvanich, Suriyan
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Flick, Denis
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Duret, Steven
Due to the high cost of mechanical refrigeration, Evaporative Cooling (EC) can be an alternative technology for small farmers in developing countries, such as Thailand. This study aimed to experimentally investigate the performance of EC using a wet fabric blanket. A real-scale cargo chamber, commonly used in Thailand, was constructed, and equipped with axial fans to simulate airflow during transportation. Two pallets of test products (hollow plastic balls) were loaded into the cargo and covered with the wet blanket. During the experiment, the inlet air velocities varied from 0.8 m s−1 to 3.6 m s−1 while the constant climate conditions were maintained (29–30 °C and 70–73 %RH). The air and product temperatures and air relative humidity were measured every minute for 3 h using thermocouples and hygrometers, respectively. The proposed EC method allowed the air temperature to decrease by approximately 3–4 °C. When the inlet air velocity decreased, a lower temperature reduction was observed. Simplified heat and mass transfer models were developed to interpret the load temperature evolution from the inlet to the outlet positions at different air velocities. The comparison between the measured and calculated data revealed a maximum mean relative error of 1.2 %. The quality preservation performance was also evaluated based on lettuce mass loss. Lower mass loss was observed for the product stored inside the cargo chamber (<6 %) compared to those outside (8–10 %). This study suggests the potential use of a wet blanket as an EC cooling medium for a short-distance transport to enhance the cold chain performance in Thailand.
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Temperature control in a horticultural produce supply chain in Thailand and its influence on product quality
(2022-03-01)
Chaomuang, Nattawut
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Singphithak, Parinya
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Laguerre, Onrawee
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Suwapanich, Rachit
The present study was conducted in order to investigate the temperature conditions in the horticultural produce cold chain in Thailand, and fresh-cut baby corn was chosen for a case study. The field investigation together with in-person interviews were performed at 4 growers' premises and one packing house. The information collected provided details on current postharvest conditions at individual stages from the growers’ premises to an export distribution center. Temperature measurements were carried out to explore the time-temperature profiles throughout these stages. The results showed that the total duration of these stages was almost 32 h, and the temperature variations were between 6 and 33 °C. Precooling was delayed for at least 9 h, since baby corn cobs were primarily processed by dehusking and bulk packing. The baby corn was maintained at a temperature below 6.0 °C in a cold room for almost half of the total duration. The effect of the postharvest temperature conditions on the product quality evaluation was assessed by measuring various physiological quality attributes during storage. It was found that the marketability of the baby corn subjected to such postharvest temperature conditions remained possible with a salable period of up to two weeks. The result made it possible to identify the stages during which temperature control was inadequate, and recommendations were proposed to the stakeholder partner in order to modify the postharvest conditions in order to extend the product shelf life.

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