Enhancing the shelf-life of washed eggs using a gelatin-based coating enriched with pomegranate peel extract under tropical storage conditions

Abstract

Egg washing effectively improves food safety but accelerates quality deterioration by removing the natural cuticle, especially during ambient storage. This study investigated the efficacy of a gelatin-based edible coating incorporated with pomegranate peel extract (PPE) in preserving the internal quality of washed chicken eggs stored at room temperature (25–30°C). Eggs were assigned to four treatments: uncoated control (UC), gelatin-only (GEL), and gelatin containing 1.0% (GEL-PPE1.0) or 1.5% PPE (GEL-PPE1.5), and evaluated over 28 days. The results showed that GEL-PPE1.5 significantly outperformed other groups in preserving internal quality (P ' 0.05). By Day 28, the GEL-PPE1.5 group maintained a Haugh unit (HU) of 55.59 ± 9.42, whereas the UC group dropped to 33.73 ± 17.29 (P ' 0.001). Similarly, the yolk index (YI) of the GEL-PPE1.5 group was 0.21 ± 0.02, compared to 0.11 ± 0.03 in UC eggs. The PPE coatings also moderate pH shifts; the albumen pH of the GEL-PPE1.5 group remained at 9.16 ± 0.20, significantly lower than the 9.61 ± 0.14 in the UC group (P ' 0.05). No microbial growth was detected in any treatment (' 10 CFU/g). The preservation efficacy arises from synergistic mechanisms: the gelatin matrix acts as a physical barrier to gas exchange, while the ellagic acid-rich PPE enhances biochemical stability by mitigating oxidative degradation. These findings demonstrate that PPE-fortified gelatin coatings provide a practical and bioactive strategy for maintaining egg freshness, offering a clear magnitude of protection for washed eggs in supply chains where refrigeration is limited.