Master of Science (MS)
School of Nutrition and Food Sciences
Mineral oil (MO) is currently used for coating eggs to preserve quality. Chitosan possesses inherent antimicrobial and film-forming properties. Chitosan coating (CH) is dried much faster than MO when applied on egg shell. Information on synergistic effects of MO:CH emulsion coatings on egg quality does not exist. We developed MO:CH emulsion coatings, and evaluated their effects on internal quality and shelf-life of eggs during storage. In the first study, MO, CH and three emulsions (MO:CH = 75:25, 50:50, and 25:75) were evaluated during 5 weeks at 25°C. Haugh unit (HU) and yolk index values decreased whereas weight loss increased during storage. Noncoated eggs changed from AA to C grade after 3 weeks. However, all emulsion-coated eggs maintained an A-grade for 4 weeks. All emulsion-coated eggs had weight losses <1.5%. Only 25:75 MO:CH emulsion-coated eggs were not sensorially glossier than noncoated eggs. All emulsion-coated eggs had >80% positive purchase intent and were negative for Salmonella spp. In the second study, 25:75 MO:CH emulsions prepared with four different emulsifier types were evaluated during 5 weeks at 25 °C and 20 weeks at 4 °C. All emulsion-coatings minimized weight loss (<1.5%) and preserved internal quality of eggs for at least 3 weeks longer than observed for noncoated eggs at 25 °C. At 4 °C, all coated eggs changed from AA to A grade after 5 weeks and maintained this grade up to 10 weeks with weight losses <2% at refrigeration. The emulsifier type generally did not insert significant effect on the internal quality. In the third study, MO and 25:75 MO:CH emulsion were evaluated during 5 weeks at 25°C using eggs from three different albumen qualities, expresed as HU, before coating: ‘High’=87.8 HU, ‘Medium’=75.6 HU and ‘Low’=70.9 HU. MO and/or 25:75 MO:CH coatings could preserve the internal quality for at least 4 more weeks for ‘High’ HU eggs; all with weight losses <0.92%). This study demonstrated that MO:CH emulsion coatings could preserve the internal quality of eggs and prolong their shelf life.
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Torrico, Damir Dennis, "Effects of emulsion coatings on the internal quality and shelf life of eggs" (2010). LSU Master's Theses. 74.