Optimization of Ultrasound-Assisted Enzymatic Preparation and Structural Characteristics of Dipeptidyl Peptidase-IV Inhibitory Peptides from Ovine Bones
QIAN Min, XIA Lingyan, XU Ye, TIAN Jianjun, JIN Ye
1. College of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China; 2. Integrated Research Base for Fresh Beef and Lamb Processing Technology, Ministry of Agriculture and Rural Affairs, Hohhot 010018, China
Abstract：To enhance the resource utilization efficiency and high-value development of ovine bone by-products, an ultrasound-assisted enzymatic hydrolysis method was employed in this study for the preparation of dipeptidyl peptidase-IV (DPP-IV) inhibitory peptides from ovine bones. The process conditions were optimized using response surface methodology with DPP-IV inhibition rate as the response variable. A comparative evaluation was performed on the microstructure of hydrolysates obtained with and without ultrasonic assistance. The results indicated that ovine bones had a high protein content and were rich in proline and alanine, thereby being suitable for the preparation of DPP-IV inhibitory peptides. Papain was identified as the most effective protease to release DPP-IV inhibitory peptides. Under ultrasound pretreatment, the DPP-IV inhibition rate was significantly increased from (54.70 ± 0.42)% to (60.61 ± 0.78)% (P < 0.05). The optimal process conditions were determined were as follows: ultrasonic power 410 W, ultrasonic time 30 min, hydrolysis temperature 54 ℃, hydrolysis pH 5.8, and hydrolysis duration 4 h. The DPP-IV inhibition rate of the hydrolysate under these conditions was (61.52 ± 0.37)%. Structural characterization revealed that ultrasound pretreatment caused transformation of the secondary structure of the hydrolysates from α-helix to random coil and β-sheet, thereby exposing more hydrophobic groups. Microstructural observation demonstrated that the particle size of the hydrolysate was reduced with ultrasound pretreatment, with smaller, denser and more uniformly distributed pores on the surface. Accordingly, ultrasound pretreatment was beneficial for the enzymatic hydrolysis process.
2026, Vol. 40 
