Valorization of Egg Shell Membrane as Protein Source in Soft Gel Capsules

Egg shell membrane (ESM) due to its high protein content can be a good protein source, but it is not utilized due to its strong connection to the shell and its poor solubilization. Thus, separation of ESM from the shell, its solubilization and its use as a protein supplement as soft gel capsules are prompted in the study. Separation of egg shell membrane (ESM) from the shell by EDTA, acetic acid, HCl and water and following solubilization by sodium dodecyl sulphate (SDS) and trinitron X (T) at 0.1, 0.5, and 1.0% concentrations up to 1440 min retention time revealed that 100 mM EDTA at 1:20 and 1:40 ratios and water at 1:40 ratio gave the highest protein concentration after washing. Ovocleidin-17, ovocleidin-23, lysozyme, ovomucoid, ovalbumin, and avidin with 17 different amino acids were detected in ESM proteins. Soluble ESM proteins had moderate water holding (11.70 ± 1.78–13.00 ± 0.77 g/g) and oil holding capacities (10.60 ± 2.09–11.52 ± 1.18 g/g) with emulsion stability and emulsion activity indexes of 0.06 ± 0.01–15.21 ± 0.37% and 0.0000 ± 0.000–0.0212 ± 0.003 \({{\text{m}}}^{2}\) ${\text{m}}^2$ /g, respectively. Formulated soft gel capsules containing 1.03 mg/g-1.45 mg/g of ESM protein had the shelf life of 32 weeks at + 4 °C. It was concluded that soluble ESM proteins can be utilized as protein supplements in soft gel form.