Effect of ultrasound treatment on thawing process of frozen tofu prepared with different salt coagulants

• Published in: Ultrasonics sonochemistry Vol. 99; p. 106578
• Main Authors: Lei, Wenhua, Zhu, Ying, Zhu, Xiuqing, Huang, Yuyang, Liu, Linlin, Lü, Mingshou, Sun, Bingyu
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2023; Elsevier
• Subjects: Coagulant; Original; Thawing rate; Tofu; Ultrasound; Water transfer; Coagulant; Thawing rate; Ultrasound; Tofu; Water transfer
• ISSN: 1350-4177; 1873-2828
• DOI: 10.1016/j.ultsonch.2023.106578

•Effects of ultrasound-assisted water thawing at different power levels on the thawing rate and gel properties of frozen tofu made using three different salt coagulants were investigated.•Elucidated the mechanism of ultrasound-assisted water thawing of frozen tofu.•Demonstrated its ability to enhance the network structure of ultrasound-assisted water thawing frozen tofu.•Offer theoretical support for improving the frozen tofu thawing process while ensuring optimal final product quality.•Provide a scientific foundation and theoretical guidance for improving the thawing performance of high-quality frozen tofu. This study investigated the effects of ultrasound-assisted water thawing (UWT) at different power levels (0, 100, 150, 200, and 250 W) on the thawing rate and gel properties of frozen tofu made using three different salt coagulants (CaCl2, CaSO4, and MgCl2). Tofu produced with CaCl2 and CaSO4 elicited gel structures with dense and homogeneous networks, while that with MgCl2 had rough pores and irregular networks. UWT treatment significantly decreased thawing time by 30.9–53.5% compared to the control. Water holding capacity and scanning electron microscopy analyses demonstrated that UWT-100, UWT-150, and UWT-200 should be used to increase the amount of fixed water for CaCl2, CaSO4, and MgCl2. These findings suggest that appropriate ultrasonic treatment could improve the water retention capacity of the tofu network and make the gel network structure more compact. Additionally, protein structural analysis showed a decrease in the exposure of hydrophobic groups and reduced protein denaturation when tofu prepared with all the coagulants were thawed with UWT energies of 100–200 W ultrasonication. These findings offer theoretical support for improving the frozen tofu thawing process while ensuring optimal final product quality.