La Choviya Hawa, Elian Nafissatun Nisa, Yusuf Hendrawan, Nabila Intan Milania, Lita Puspita Rizka Perdana
This study aimed to compare pretreatment and temperature in influencing drying characteristics, modeling, physicochemical, and thermal properties during drying. Drying bilimbi using the hot air drying method with variations in pretreatment and temperature. The increase in temperature is linear with water loss and weight reduction. The increase in temperature tends to accelerate the drying process and shorten the drying time. The increase in temperature tends to increase the drying rate and moisture diffusivity during the process. Thermal conductivity and specific heat capacity increase with moisture content and vice versa. The Modified Page model best describes the drying kinetic behavior of bilimbi based on the model accuracy test. Based on the color attribute ∆E, hot water blanching at temperature variations has the most significant change. In addition, shrinkage changes with hot water blanching have the most significant value compared to steam blanching. FTIR analysis indicates similarities in the functional groups of compounds for all pretreatment in the single bond, double bond, and fingerprint zones. One peak in the triple bond zone is functional group of Nitrogen multiple and cumulated double bond compound (Isothiocyanate) found in hot water blanching. The microstructure of the dried bilimbi surface shows that hot water blanching at various temperatures causes significant damage. Overall, it shows that steam and hot water blanching perform well on all parameters. The results suggest that proper pretreatment improves the quality of dried bilimbi. Further studies are recommended to optimize pretreatment and drying methods. However, future research could explore the commercial application of dried bilimbi products in the food industry. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2026.
Department of Biosystems Engineering, Faculty of Agricultural Technology, Brawijaya University, East Java, Malang, Indonesia
