Evaluation of the continuous flash vacuum expansion process of Andean blackberry puree: heat transfer modeling, product quality, and techno-economic feasibility

Flash vacuum expansion is an emerging thermophysical technology that combines rapid fruit heating with instantaneous decompression in a vacuum chamber to obtain high-quality purees. To date, this technology has been mainly studied in batch systems, with limited evidence regarding its application in small and medium-scale agro-industries. This study evaluated the technical performance and techno-economic feasibility of a continuous flash vacuum expansion process for the production of Andean blackberry puree. A 2 × 2 factorial design was applied, testing two heating times (48 and 67 s) and two feed rates (4 and 6 kg·min⁻¹). Heat transfer was modeled using a transient conduction–convection approach with temperature-dependent properties. Product analyses included microbial inactivation, retention of cyanidins, ellagitannins, and ascorbic acid (UHPLC-DAD), as well as the evaluation of texture, color, and sensory attributes. The optimal condition (48 s, 6 kg·min⁻¹) achieved a 72% yield, a 7-log microbial reduction, and a 77% increase in cyanidin content compared with the untreated puree. Ellagitannins, ascorbic acid, and sensory attributes were preserved, confirming the high functional quality of the product. Economic projections over 15 years indicated a payback period of approximately two years and an internal rate of return of 93%, surpassing values commonly reported for conventional fruit-processing technologies. These results demonstrate, for the first time, that continuous flash vacuum expansion at industrial scale ensures microbial safety, enhances bioactive compound retention, and represents a technically and economically viable alternative for small and medium-scale agro-industries.