Effects of ultrasound pretreatment on the drying kinetics, water status and distribution in scallop adductors during heat pump drying

Abstract

BACKGROUND: A material's physical and chemical properties during drying are influenced by water status and distribution. However, merely overall water removal is reported in many investigations, which hinders clarification of the drying mechanism. Therefore, the effects of ultrasound (US) pretreatment (0 W, CK; 90 W, US-90; 180 W, US-180) on the drying kinetics and quality of heat pump drying (HPD) scallop adductors was performed based on low-field nuclear magnetic resonance (LF-NMR).RESULTS: Compared with CK, effective moisture diffusion coefficient was increased by 12.43% and 23.35% for US-90 and US-180, respectively. The Weibull model satisfactorily described the drying characteristics with a high r 2 (> 0.998), low rmse (< 0.0120) and χ 2 (< 0.00008). LF-NMR revealed that the immobilized water was predominant in scallop adductors. As drying proceeded, the relaxation time of free and immobilized water was decreased sharply, whereas the relaxation time of bound water scarcely changed. The time required to reduce approximately two-fifths of the original peak area of immobilized water was 720, 630 and 540 min for CK, US-90 and US-180, respectively. The amplitude of immobilized water was decreased and bound water increased significantly, although free water was kept constant (ranging 1-2%). US pretreatment reduced total color difference and hardness, but enhanced the toughness of dried scallop adductors. However, US had no significant influence on the product rehydration rate and shrinkage rate. CONCLUSION: LF-NMR was successfully employed to evaluate the drying degree of scallop adductors. US facilitated the conversion of immobilized water to free water and, consequently, promoted water removal during HPD.

Impact of pretreatments with ethanol and freezing on drying slice papaya: drying performance and kinetic of ultrasound‐assisted extraction of phenolics compounds

“…2). These data agree with previous studies carried out by many researchers 17,23,40,6,41 using different drying pretreatments.…”

“…2). These data agree with previous studies carried out by many researchers 17,23,40,6,41 using different drying pretreatments. Note that the simulations performed using model 2 generated curves (Fig.…”

Heat Pump Drying of Kelp (Laminaria japonica): Drying Kinetics and Thermodynamic Properties

“…The gaseous refrigerant is compressed into a high-temperature, high-pressure gas, which then enters the condenser to release heat to the drying medium (air), repeating the cycle until the material is dried. Heat pump drying is suitable for the large-scale processing of aquatic products [10] and has been successfully applied to kelp knot [11], scallop adductors [12], squid fillets [13], banana slices [14], grape pomace [15], and lignite [16].…”

Effect of Heating on Protein Denaturation, Water State, Microstructure, and Textural Properties of Antarctic Krill (Euphausia superba) Meat

“…Moisture content and water state are attributes that are closely related to meat texture. Proton spin-spin relaxation times (T 2 ) can explain mobility and degrees of freedom of water molecules, thus re ecting water dynamic properties such as diffusion and state (Zhu et al 2021). LF-NMR is a commonly used to characterize hydrogen protons in different matrices.…”