Instant controlled pressure drop (DIC) as an effective pretreatment to intensify drying efficiency and enhance quality attributes of heat pump dried scallop adductors

Scallop adductors (SA) with a moisture content (MC) of 65% (H-65), 55% (H-55), 45% (H-45), and 35% (H-35) were subjected to an instant controlled pressure drop (DIC) pretreatment to investigate its influence on the subsequent heat pump drying kinetics and quality attributes. SA without DIC was performed for comparison (CK). Compared to the CK, DIC resulted in a decreasing rate of 5.88–35.29% in the drying time, but an increasing rate of 11.12–46.89% in effective moisture diffusivity coefficient depending on samples' MC. After DIC, SA showed a decrease in α-helices and β-turns, but an increase in β-sheets, and a sharp decrease in the relaxation time and proportion of the immobilized water. DIC increased total color difference (expect H-45), hardness, rehydration ratio, but decreased shrinkage rate (except H-65) compared to the CK. DIC is a promising pretreatment for intensifying drying efficiency, inhibiting volume shrinkage, and improving rehydration capacity of SA.