Effects of Different Drying Methods on the Meat Quality and Characteristic Flavor Compounds of Pacific White Shrimp

Abstract

Drying is widely used to extend the shelf life of Pacific white shrimp, yet different drying routes can shift meat quality and flavor formation in distinct ways. This study compared fresh shrimp (Ctrl), vacuum freeze-dried shrimp (VFD), heat-assisted vacuum freeze-drying shrimp (HAFD), hot-air-dried shrimp (HAD), and air-frying-assisted dried shrimp (AFD) by analyzing proximate composition, color, texture, free amino acids (FAAs), 5′-nucleotides, organic acids, electronic sensory fingerprints, and volatile compounds. Drying concentrated protein, fat, and ash also changed color and texture. VFD produced the lightest samples and the largest color difference, whereas HAD and AFD caused stronger hardness and adhesiveness. HAFD showed the most favorable non-volatile umami profile, with the highest total FAAs, umami FAAs, guanosine 5′-monophosphate (GMP), and equivalent umami concentration (51.35 g monosodium glutamate (MSG)/100 g). VFD retained the highest total 5′-nucleotides, whereas HAD generated the highest succinic acid and the strongest organic-acid-derived taste activity. Electronic nose and tongue analyses separated Ctrl/VFD from HAD/AFD along the main axis of principal component analysis (PCA), indicating that heat involvement reshaped aroma and taste fingerprints. Headspace solid-phase microextraction–gas chromatography–mass spectrometry (HS-SPME–GC–MS) identified 51 volatile compounds. HAD showed the highest total pyrazines, esters, alcohols, and ketones, whereas AFD showed the highest aldehyde abundance. Overall, HAFD balanced quality retention and umami enhancement better, whereas HAD and AFD promoted stronger roasted-aroma formation. These findings provide guidance for selecting drying strategies according to target dried-shrimp flavor profiles and desired balances between mild umami and intense roasted aroma.