Development and Stepwise Optimization of Freeze-Dried Seasoning Cubes From Traditional Fish Sauce: A Postharvest Approach for Value-Added Aquatic Products.

This study focuses on the technological development of freeze-dried seasoning cubes from traditional Vietnamese fish sauce (60°N), aiming to improve postharvest stability and product versatility. Formulation trials were conducted by blending fish sauce with calamansi juice, garlic, chili, sugar, and maltodextrin to optimize flavor balance and structural integrity. Multistage freeze-drying (10°C-50°C) was applied to evaluate the effects of drying temperature on moisture removal, structural properties, sensory quality, and retention of bioactive compounds. The optimal formulation (1:1 dilution, 10% calamansi, 15% garlic, 10% chili, 20% sugar, and 25% maltodextrin) combined with a final drying temperature of 50°C produced compact, well-defined cube-shaped products (approximately 25 × 25 × 8 mm) with a stable porous internal matrix and a smooth, nonsticky surface. The optimized cubes achieved a final moisture content of 2.79%, a sensory acceptance score of 4.50 ± 0.18, and retained considerable levels of bioactive compounds, including 44.64% DPPH radical scavenging activity, 21.15 mg GAE/100 g total polyphenols, and 24.75 mg AA/100 g vitamin C. These findings demonstrate a practical postharvest strategy to transform traditional liquid fish sauce into convenient, value-added aquatic products suitable for broader culinary and export applications.