Large-scale purification of ovalbumin using polyethylene glycol precipitation and isoelectric precipitation

Abstract

In addition to small amounts of minerals and carbohydrates, most of the dry matter of chicken egg white is protein, making egg white an ideal resource for obtaining food proteins. Ovalbumin (OVA), which accounts for more than 50% of the total egg white protein, is one of the most widely studied food proteins due to its multiple functional properties, and it has also been used as a model protein molecule in many research fields. The objective of this study was to develop a simple and rapid method for the purification of OVA from egg whites on large scale. First, OVA was separated from ovomucin, ovotransferrin, and ovomucoid by polyethylene glycol (PEG) concentration, using the following optimal parameters: the PEG concentration was 15%, the pH was 6.5, the salt concentration was 100 mmol/L, and the operating temperature was 10°C. The OVA-rich supernatant obtained from PEG precipitation was further purified by isoelectric precipitation at a pI of 4.5 and a temperature of 4°C, and the purified OVA was obtained with at a purity of 95.1% by HPLC, with a yield of 46.4%. After the extraction of OVA, the PEG solution was vacuum dried and then utilized cyclically in the PEG precipitation steps. The whole purification process could be finished within 2 to 3 h at a scale of several kilograms of egg white. This method has the advantages of rapidity, simplicity, low cost, and ease of scalability.

A puzzle piece of protein N-glycosylation in chicken egg: N-glycoproteome of chicken egg vitelline membrane

“…The supernatant was collected by centrifugation at 8000 × g at 4 °C for 10 min. Finally, the protein concentrations of the extracted samples were determined with a BCA kit (P0010, Beyotime Institute of Biotechnology, Shanghai, China) [ 12 , 13 ].…”

Collagen Extracted from Bigeye Tuna (Thunnus obesus) Skin by Isoelectric Precipitation: Physicochemical Properties, Proliferation, and Migration Activities

“…Isoelectric precipitation is based on the principle that proteins have their lowest solubility at their isoelectric point and that different proteins have different isoelectric points. Isoelectric precipitation has been used for the separation and purification of proteins such as PSE-like chicken protein [19], walnut protein [20], Chinese quince seed protein [21], and ovalbumin [22]. However, there are few reports demonstrating the use of isoelectric precipitation for the recovery and purification of collagen.…”

Proteins associated with quality deterioration of prepared chicken breast based on differential proteomics during refrigerated storage

“…The mixtures were boiled at 95°C for 15 min and refrigerated at −20°C; the supernatants were loaded on 5% concentrated gel SDS-PAGE. 25 Furthermore, the gel was run at 120 V until the dye appeared at the bottom. Typically, 200-400 μg tissue was analyzed for each western blotting.…”