Dual-Frequency Ultrasound-Assisted Glycation Modulates Beef Myofibrillar Protein Gels and Inhibits Lysinoalanine Formation.

Ultrasound-assisted xylose glycation is found to be an effective method to improve the gel properties, functional properties and structural characteristics of meat proteins, and to some extent minimize the generation of protein cross-linking. The effects of dual-frequency ultrasound-assisted (20/25, 20/28, 25/28, 20/40, 25/40, 28/40, 28/68, and 40/68 kHz) xylose glycation on beef myofibrillar proteins (MPs) were evaluated in the study. Compared with the control, dual-frequency ultrasound promoted glycation in a frequency-dependent manner. The highest grafting degree was observed at 20/25 and 25/40 kHz, reaching 37.05% and 38.47%, respectively. For gel-type applications, 25/28 kHz ultrasound provided the most balanced performance. It reduced cooking loss from 79.80% to 73.77%, increased hardness from 1388.18 to 1743.38 g, and increased chewiness from 673.03 to 939.84 g. This treatment also showed favorable emulsifying behavior. The strongest LAL inhibition occurred at 25/40 kHz, where LAL decreased from 7961.24 to 4868.88 mg/kg, corresponding to a 38.8% reduction. Structural analyses indicated that ultrasound-assisted glycation induced MP unfolding, thiol exposure, hydrophobic rearrangement, and oxidative modification to different extents. Overall, 25/28 kHz may be more suitable when balanced gel quality, emulsifying performance, and safety control are required. In contrast, 25/40 kHz may be preferred when LAL reduction is the primary objective.