Effects of ultrasound on the physicochemical properties and microstructure of salted‐dried grass carp (Ctenopharyngodon idella)

Abstract

AbstractUltrasound treatment was used for accelerating drying process and shortening drying time of salted‐dried grass carp, in parallel with evaluation of physicochemical properties and microstructure. The grass carp blocks were salted with ultrasound‐assisted treatment at 0–480 W, 40 kHz for 120 min, then put into heat pump dryer for drying at 50% humidity, 30 °C for 50 hr. The moisture content results showed that ultrasound treatment could significantly promote water loss rate. As the ultrasound power increased, the hardness, the relative content of monounsaturated fatty acid and polyunsaturated fatty acid and total content of free amino acid decreased while the saturated fatty acid and sensory scores increased, respectively. Furthermore, microstructure of the dried‐salted grass carp was studied using paraffin sections and the scanning electron microscope to understand the change of microstructure. In general, ultrasound‐assisted salting significantly increased drying rate, and improved the quality of salted‐dried grass carp. This study shows the potential application of ultrasound in food drying process.Practical applicationsThe ultrasound was applied in order to facilitate the traditional process to produce salted‐dried grass carp. And physicochemical properties and microstructure of salted‐dried fish were measured. The results showed that the application of ultrasound could significantly promote the mass transfer of water and improved the product's appeal for customers. The outcome of this study demonstrated a method for producing better quality dried‐salted fish products with a fast speed in the future and showed a great potential of ultrasound in food drying process.