Dipeptidyl peptidase IV (DPP-IV) inhibitory properties of camel milk protein hydrolysates generated with trypsin

Dipeptidyl peptidase IV (DPP-IV) inhibitory peptides were identified in silico within camel milk proteins. Camel milk was hydrolysed with trypsin using a design of experiments (DOE, temperature (40–60 °C), enzyme to substrate (E:S) ratio (0.50–2.00% (w/w)) and time (60–240 min)). Fifteen hydrolysates (H1–H15) having DPP-IV half maximal inhibitory concentration (IC₅₀) values between 0.52 ± 0.06 (H9) and 1.26 ± 0.13 (H1) mg mL⁻¹ were produced. Camel and bovine milk proteins hydrolysed at 40 °C, 1.8% E:S and 218 min had DPP-IV IC₅₀ values of 0.68 ± 0.08 and 0.85 ± 0.10 mg mL⁻¹ (p < 0.05), respectively. Potent and unique DPP-IV inhibitory peptides (Leu-Pro-Val-Pro-Gln and Trp-Lys) were identified in camel milk protein hydrolysates, which were not present in bovine milk protein hydrolysates. The DPP-IV inhibitory properties of camel milk peptides were reported for the first time in this study. Camel milk is an interesting substrate to further investigate for its antidiabetic potential.