Food Production, Processing and Nutrition · Published 2026-07-14 · DOI 10.1186/s43014-026-00410-y
Withu Choosri, Touchpong Choosri
Abstract This study investigated the effects of low-duty-cycle intermittent hot-air drying on drying kinetics, mass transfer, quality attributes, and energy-related performance indicators of pineapple slices (Ananas comosus L., cv. Pattavia). Experiments were conducted at 60 °C and an air velocity of 1.0 m/s under continuous drying (TPR0) and intermittent heating conditions (TPR8, TPR10, and TPR12) with a 20 s heating pulse followed by variable OFF periods. Drying behavior was analyzed using thin-layer models, drying kinetics, effective moisture diffusivity, shrinkage, color parameters, and rehydration characteristics. All models adequately described the experimental data (R 2 > 0.996), with the Midilli model providing the best fit. Among all treatments, TPR8 exhibited the most favorable performance, reducing drying time by 12.5% and increasing the maximum drying rate by 18.1% compared with continuous drying. Effective moisture diffusivity was also enhanced under moderate intermittency, indicating improved internal moisture transport. Quality analysis showed that intermittent heating did not significantly affect color attributes or rehydration capacity (p > 0.05). Shrinkage was slightly reduced under TPR8, suggesting improved structural retention. Energy-related performance was evaluated using air-side thermal utilization efficiency ( $${\eta}_{air}$$ η air ) and estimated specific electrical energy consumption (SEC). TPR8 exhibited the highest $${\eta}_{air}$$ η air (1.41%) and the lowest SEC (107.66 kWh/kg water evaporated), indicating improved air-side heat utilization and reduced estimated energy demand. However, these values are based on simplified air-side energy analysis and rated power assumptions rather than direct electrical measurements. Overall, low-duty-cycle intermittent hot-air drying at moderate intermittency (TPR8) enhanced drying kinetics and mass transfer while maintaining product quality and improving energy-related indicators. These findings demonstrate the potential of intermittent heating as a process intensification strategy for convective drying of pineapple slices. Further studies incorporating direct power measurement and exergy analysis are recommended to better quantify system-level energy performance. Graphical Abstract
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Choosri, W., Choosri, T. (2026). Enhancement of drying kinetics, quality attributes, and thermal efficiency of pineapple slices using low-duty-cycle intermittent hot-air drying. Food Production, Processing and Nutrition. https://doi.org/10.1186/s43014-026-00410-y