Functional properties and adipogenesis inhibitory activity of protein hydrolysates from quinoa (Chenopodium quinoa Willd.)

The functional properties and adipogenesis inhibitory activity of quinoa protein hydrolysates, prepared using papain, pepsin, and pancreatin for 0, 30, 60, 90, and 120 min, were studied. For these three kinds of proteases, the solubility of the hydrolysates significantly increased with the increasing DH in pH range of 3-8, while the EAI and ESI of these hydrolysates significantly decreased during hydrolysis. The anti-inflammatory activity of these protein hydrolysates was measured. All of these protein hydrolysates showed high anti-inflammatory activity. However, there was no significant difference in anti-inflammatory activity between protein hydrolysates and total protein from quinoa. These protein hydrolysates also inhibited lipid accumulation during differentiation within the range of concentrations of 0-1,600 μg/ml, which exerted no cytotoxicity toward 3T3-L1 cells. The protein hydrolysates from quinoa prepared using pepsin for 120 min (PEP-120) had the highest activity with an IC₅₀ value of 786.58 μg/ml. Moreover, LC-MS/MS analysis of PEP-120 showed that five main bioactive peptides, which have been demonstrated to have ACE inhibitor, antioxidant, and antithrombotic activities, were present in PEP-120. In addition, gene expression and Western blot analysis revealed that PEP-120 suppressed the 3T3-L1 cell differentiation through the peroxisome proliferator-activated receptor γ (PPARγ) pathway.