Effect of heat-treatment times on the microstructure and water absorption properties of sea cucumber

In order to explore the relationship between water absorption properties and microstructure changes of sea cucumber body wall with different heat treatments. The microstructure, rheological characteristics and hydrogen bond content changes of sea cucumber body wall at different heat-treatment times (4, 6, 8, 10 and 12 h) were investigated, as well as the distribution and phase of water during the soaking. The results showed that the heat treatment for 4 and 6 h mainly caused fibre fracture which led to more water binding sites and free water content. With prolonged heat-treatment times, the degree of denaturation increases. The micro-pores formed at 10 h heat treatment could accommodate the highest free water content, and the network structure was more intensive at 12 h with decreased porosity. The apparent viscosity, storage and loss modulus gradually decreased with heat-treatment time, and the liquidity increased. Extended heat-treatment time led to the breakage of the microstructure, and the longer time required for its free water and immobile water content to reach the maximum. However, the trend of bound water was the opposite.