Mechanistic study on ultrasound-assisted rehydration and heating processes of dried seafood: Promoting moisture...

Significant changes were observed in the microstructure and water distribution of dried seafood following ultrasound-assisted rehydration and heat processing. The rehydration ratios of sea cucumber (SC), abalone (AB), and fish maw (FM), after temperature-time coupled ultrasonic rehydration (TCU), increased to 220.65 ± 7.02%, 231.00 ± 9.54%, and 471.81 ± 66.88%, respectively, compared with the traditional process, while favorable textural properties were retained (the hardness and chewiness of SC reached 6.59 ± 3.94 N and 61.15 ± 39.55 mJ). The transverse relaxation time increased to 284.80 ms (AB), and the formation of a loose and porous structure facilitated moisture penetration. After heat processing (90 °C for 10-50 min), fiber breakage was induced, and free amino nitrogen content of FM increased from 12.11 ± 0.66 μmol/g to 41.30 ± 1.05 μmol/g, which may be due to the cleavage of collagen secondary bonds and unfolding of triple helix structure.