Abstract: Ultrasound has a variety of physical and sonochemical effects, which can lead to physicochemical changes in foods. This study evaluated the effects of ultrasound-assisted curing on water loss, the concentrations of soluble substances and myoglobin in NaCl solution, drying rate, lipid oxidation, tenderness and microstructure of beef jerky. The results showed that the application of ultrasound during the curing process increased water loss significantly (P < 0.05), which had a positive correlation with ultrasound power and processing time. The water loss of beef slices treated at 0.60 W/cm2 ultrasound intensity for 60 min was the highest (6.93%), while the control without ultrasound treatment absorbed 6.14% water. Ultrasound processing promoted protein dissolution from beef significantly (P < 0.05), but excessively high ultrasound intensity could lead to a decrease in protein dissolution. Ultrasound treatment significantly promoted myoglobin dissolution and lipid oxidation (P < 0.05), and the effect was positively correlated with ultrasonic power and processing time. Additionally, the shear force of beef slices decreased significantly (P < 0.05) after ultrasound treatment at 0.30 or 0.60 W/cm2 for 60 min, but there was no significant difference under the other conditions investigated. Histological observation with hematoxylin-eosin staining confirmed that ultrasound treatments for 30 and 60 min at 0.60 W/cm2 could cause different degrees of damage to beef muscle fibers. In conclusion, the application of ultrasound in beef jerky processing can reduce the product hardness and shorten the drying time without any significant adverse effects.

Key words: ultrasound, beef, myoglobin, drying rate, lipid oxidation, microstructure