Chitosan-coated Eggshells Help Slow the Deterioration of Internal Egg Quality During Storage at Room Temperature under Tropical Conditions

Abstract

Egg deterioration during room-temperature storage is a major challenge in tropical regions lacking practical refrigeration. While chitosan coatings preserve eggs, research on how different concentrations perform under tropical ambient conditions remains limited. Therefore, this study evaluated the concentration-dependent effects of chitosan coatings on internal egg quality during extended room-temperature storage. A total of 360 freshly laid chicken eggs were randomly assigned to four treatments: non-coated eggs (NC), eggs coated with 1% acetic acid (AC), eggs coated with 1% chitosan solution (1CS), and eggs coated with 2% chitosan solution (2CS). Eggs were stored at tropical room temperature for 35 days, and egg weight loss, Haugh Unit (HU), and albumen pH were evaluated at weekly intervals. Egg weight loss increased progressively in all treatments throughout storage. Although chitosan-coated eggs tended to exhibit lower cumulative weight loss than the NC and AC groups, differences among treatments were not statistically significant (P > 0.05). In contrast, chitosan coating significantly affected internal egg quality parameters. Chitosan-coated eggs maintained significantly higher HU values during storage than non-coated or acetic acid-treated eggs (P < 0.05), demonstrating superior preservation of internal quality. Similarly, albumen pH increased in all treatments during storage; however, the increase was significantly slower in chitosan-coated eggs (P < 0.05). These results suggest that chitosan coatings may act as semi-permeable barriers, reducing moisture and gas exchange to slow deterioration in internal egg quality during storage. Notably, the 2% chitosan treatment provided the greatest preservation effect, maintaining substantially higher HU values at the end of the 35-day storage period than the control treatments. Visually, eggs coated with 2% chitosan maintained Grade B quality after 40 days of storage, suggesting extended marketability under tropical ambient conditions. However, longer storage periods and quantitative evaluations are needed to confirm the exact shelf-life extension. In conclusion, chitosan coating effectively delayed the deterioration of internal egg quality during room-temperature storage, with the 2% concentration providing the greatest protective effect. This study supports using concentration-dependent chitosan coatings as an eco-friendly way to preserve egg quality in tropical areas with limited refrigeration.