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.
| Identifer | oai:union.ndltd.org:LSU/oai:etd.lsu.edu:etd-10252010-144437 |
| Date | 26 October 2010 |
| Creators | Torrico, Damir Dennis |
| Contributors | Ge, Beilei, Xu, Zhimmy, Prinyawiwatkul, Witoon |
| Publisher | LSU |
| Source Sets | Louisiana State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lsu.edu/docs/available/etd-10252010-144437/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached herein a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to LSU or its agents the non-exclusive license to archive and make accessible, under the conditions specified below and in appropriate University policies, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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