Natural coating based on watermelon rind pectin and carnauba wax for preserving egg quality in tropical conditions

Coating provides an effective approach to prolong egg freshness by forming protective barriers that reduce moisture and gas loss through eggshells. Natural coatings derived from watermelon rind pectin (WRP) and carnauba wax (CW) were investigated as alternatives to refrigeration for preserving egg quality under tropical storage. Fresh eggs were coated with WRP, CW, or WRP+CW and compared with uncoated eggs stored at room temperature (29 ± 3.2 ° C; 65 ± 5% RH) (control or URT) and under refrigeration (U4 ° C) for 35 days. Quality parameters were assessed weekly, including weight loss, Haugh unit (HU), yolk index (YI), albumen pH, air cell height, eggshell thickness and strength, and eggshell permeability. Results showed that the WRP+CW coating significantly reduced weight loss (6.35% vs. 10.13% in uncoated eggs on day 35), maintained HU values at Grade A for up to 21 days, while the HU of uncoated eggs declined to Grade B by day 7, and limited air cell enlargement (6.3 mm vs. 7.2 mm on day 35). WRP+CW coated eggs also retained greater shell thickness and strength (0.53 mm and 4.32 kgf) compared with uncoated controls (0.39 mm and 3.38 kgf). Blue Lake dye penetration confirmed reduced eggshell permeability, supporting the coating’s barrier function. Although refrigeration provided superior preservation, coated eggs maintained acceptable quality for 21–28 days under room temperature storage. These findings indicate WRP+CW as a practical, natural-based strategy to extend egg shelf life in regions with restricted cold chain access. • Watermelon rind pectin and carnauba wax coatings reduced weight loss, slowed albumen thinning, and strengthened eggshells under tropical storage. • Blue dye penetration confirmed the coatings lowered eggshell permeability. • Coated eggs maintained acceptable quality for up to 21-28 days at room temperature. • The coatings offer a natural-based strategy for extending egg shelf life without refrigeration.