Impact of whey protein isolate/sodium montmorillonite/sodium metabisulfite coating on the shelf life of fresh eggs during storage

Abstract

The effect of protein-based coating made with whey protein isolate (WPI), sodium montmorillonite nanoparticles (MMT-Na), and sodium metabisulfite (SMB) on the internal quality (weight loss, Haugh unit, yolk index, albumen pH, yolk pH, foam stability, and overrun) of eggs was evaluated for 8 weeks of storage at 25 ± 3 °C and 70 ± 5% RH. The coating was applied by immersion of eggs, followed by drying at room temperature. Uncoated eggs were used as a control. The coated eggs maintained grade A for up to 5 weeks, while the grade of the control eggs lasted about a week. Significant lower weight loss was observed for the coated eggs after 8 weeks of storage when compared to the control, with values of 11.65% and 14.50%, respectively. The protein-based coating improved foam stability (>75%) when compared to the control (43.45%) due to the small changes in pH of the albumen, after 5 weeks of storage. The control eggs lasted only 5 weeks under the storage conditions of this study, thus the internal quality was not determined after this period, while the coated eggs maintained integrity for up to 8 weeks.