Plasticizer Types and Coating Methods Affect Quality and Shelf Life of Eggs Coated with Chitosan

• Published in: Journal of food science 2008-04, Vol.73 (3), p.S111-S117
• Main Authors: Kim, S.H, No, H.K, Prinyawiwatkul, W
• Format: Article
• Language: English
• Subjects: Additives; application methods; Biological and medical sciences; chitosan; Chitosan - pharmacology; chitosan-coated egg; coating methods; coatings; Consumer Product Safety; Effects; Egg and egg product industries; egg weight; egg yolk; Eggs; Eggs - microbiology; Eggs - standards; Food Contamination - prevention & control; Food Handling - methods; Food industries; Food Preservation - methods; food quality; Food science; Fundamental and applied biological sciences. Psychology; glycerol; Glycerol - pharmacology; Haugh units; Humans; Microscopy, Electron, Scanning; Molecular Weight; ovalbumin; plasticizer types; plasticizers; propylene glycol; Propylene Glycol - pharmacology; quality; shelf life; sorbitol; Sorbitol - pharmacology; Time Factors
• ISSN: 0022-1147; 1750-3841
• DOI: 10.1111/j.1750-3841.2007.00650.x

Effects of different plasticizer types (glycerol, propylene glycol, and sorbitol) and coating methods (brushing, dipping, and spraying) on the internal quality and shelf life of chitosan-coated eggs were evaluated during 5 wk of storage at 25 °C. The Haugh unit and yolk index values suggested that chitosan coating, irrespective of the plasticizer types, extended the shelf life of eggs by almost 3 wk at 25 °C compared with noncoated eggs. After 5 wk of storage, plasticizer types did not significantly affect the quality (weight loss, Haugh unit, and yolk index) of chitosan-coated eggs. However, there was an observable trend indicating that use of sorbitol rather than propylene glycol and glycerol as a plasticizer was better in reducing weight loss (whole egg) of chitosan-coated eggs during a 5-wk storage. After a 5-wk storage, there were no significant differences in weight loss and weight of albumen and yolk among chitosan-coated eggs, regardless of the coating methods. However, both brushing and dipping methods yielded chitosan-coated eggs with better yolk (higher yolk index values) and albumen (lower pH) qualities than did the spraying method. During 3 to 5 wk of storage, the Haugh unit values of chitosan-coated eggs by the brushing method were higher than or comparable to those by dipping or spraying. Therefore, coating of eggs with chitosan using sorbitol as a plasticizer and by the brushing method may offer a protective barrier in preserving the internal quality and thus extending shelf life of eggs.