The chili pepper (Capsicum annuum) is among the most widely consumed vegetables worldwide, valued for its sensory and nutritional properties. Nevertheless, it is highly vulnerable to deterioration due to its elevated moisture content. Effective preservation strategies, such as the addition of salt combined with drying, are therefore crucial to maintaining quality and extending shelf life. This study employed a modified Reaction Engineering Approach (REA) to model the drying kinetics and temperature behavior of chili paste under continuous and intermittent conductive hydro-drying conditions. Thirty experiments were conducted considering various salt concentrations (0, 7.5 and 15 g salt/100 g paste), water temperatures in the hydro-dryer, and heating intermittency through on/off cycles. The modified REA model accurately predicted both moisture and temperature profiles, with determination coefficients of 0.9463 and 0.8820, respectively. In addition to direct validation with the complete dataset, cross-validation between cayenne and jalapeño varieties demonstrated the ability of the model to generalize across different formulations and structural characteristics. These results confirm the robustness of the proposed framework and its suitability as a predictive tool for heterogeneous food matrices. Direct and cross-validation confirmed strong predictive performance across all operating conditions and both chili varieties, supporting the use of the modified REA model as a robust tool for representing coupled moisture–temperature dynamics in conductive hydro-drying of semi-solid matrices. Overall, the model provides a reliable platform for analyzing, designing, optimizing, and controlling hydro-drying processes in semi-solid foods, supporting the development of more efficient and sustainable preservation strategies.
Juri-Morales et al. (2026) studied this question.