Quality and flavor attributes of Antarctic krill subjected to microwave vacuum drying and its comparison with conventional hot air drying

Drying is a pivotal technology in the deep processing of aquatic products, effectively inhibiting microbial proliferation and extending shelf life. In particular, microwave vacuum drying (MVD) enables rapid volumetric heating under reduced pressure, facilitating low-temperature dehydration that minimizes lipid oxidation, preserves umami-related compounds and volatile constituents, and limits protein denaturation. In this study, MVD parameters for Antarctic krill were optimized via response surface methodology as 1.50 kg/m2 loading capacity, 873 W microwave power, and 0.07 MPa vacuum degree. Compared to conventional high-temperature hot-air drying (100 °C, HAD), the optimized MVD regime (product temperature ≤ 50–60 °C) significantly enhanced dehydration efficiency. Within the limited scope of these two regimes, MVD attenuated sulfhydryl loss, carbonyl accumulation, and protein structural denaturation. Furthermore, volatile compound analysis revealed pyrazine enrichment, reduced aldehyde-related off-flavors, and identified nine putative odor-active compounds (OAV ≥ 1) in the MVD group. Consequently, MVD optimally retains physicochemical, nutritional, and organoleptic properties for high-quality production.