Biological activities of peptide concentrates obtained from hydrolysed eggshell membrane byproduct by optimisation with response surface methodology
The increase of hen egg consumption demands profitable applications for eggshells, including their membranes, in order to minimize environmental and public health problems that could result from their accumulation. This work presents an innovative application for eggshell membranes to obtain an added-value food ingredient that combines maximized ACE-inhibitory and antioxidant activities. Firstly, the use of acetic acid 5% (v/v); and 3-mercaptopropionic acid 1.25 M enabled 63% recovery of eggshell membrane proteins. Secondly, the extracted proteins were hydrolysed by alcalase from Bacillus licheniformis, viscozyme L and protease from Bacillus amyloliquefaciens. Hydrolysis conditions were optimized using response surface methodology experimental design. The ACE-inhibitory activity (IC50) was 34.5 ± 2.1 μg mL−1, 63.0 ± 4.2 μg mL−1 and 43.0 ± 8.5 μg mL−1 for each enzyme, respectively, and the antioxidant activity was ca. 4.0 μmoltrolox equivalent mg−1hydrolysed protein. The combination of both bioactive properties is of potential interest to control cardiovascular diseases.