Abstract

Purpose: The pisco produced in Chile is a distillate from pisco grape varieties, which generates a large amount of grape pomace. However, with the growing interest in reducing the environmental impact and converting these residues into novel by-products, the research and their evaluation in each stage can contribute significantly to ensuring their recovery. This study evaluated the kinetics of vacuum and convective drying from grape pomace at different temperatures and the influence on the retention of polyphenolic compounds and antioxidant activity as scalable alternatives for agro-industry. Methods: The pisco grape pomace was dried by two drying methods at different temperatures: Vacuum drying (50–100 °C; 100 mbar) and convective drying (40–80 °C). Liquid chromatography with diode-array detection and spectrophotometry were used to characterize the polyphenol profile and evaluate the antioxidant activity. Results: The best drying grape pomace process was vacuum drying at 60 °C with a short drying time (210 min), and diffusivity values were higher (6.64 × 10?10 m2s?1) than those obtained by other drying conditions. The model that best fits the experimental data was the Midilli Kucuk model. Vacuum drying at 60 °C obtained the highest content of polyphenols and flavonoids, and significant antioxidant capacity was obtained. The gallic acid, 4-hydroxybenzoic acid, catechin, epicatechin, and rutin were found in grape pomace. Conclusions: Vacuum drying at 60 °C is a viable alternative to stabilize pisco grape pomace, achieving good drying times and generating an environmentally friendly solution. Graphical Abstract: (Figure presented.) © The Author(s), under exclusive licence to Springer Nature B.V. 2023.