100B-40 |
Use of protein-based edible coating as a barrier of bacterial penetration into eggs |
S. K. PARK1, Y. Kim2, J. Cho3, C. O. Rhee3, and Y. H. Bae1. (1) Center for Biomaterials and Biotechnology, Department of Materials and Engineering, Kwangju Institute of Science and Technology, 1 Oryong-dong Buk-gu, Kwangju, 500-712, South Korea, (2) Center for Biomaterials and Food, Nutrapol Inc., 1 Oryong-dong, Buk gu, Kwangju, 500-712, South Korea, (3) Food Science and Technology, Chonnam National University, 300 Youngbong-dong, Kwangju, 500-757, South Korea This research was to produce edible coatings/films with soy proteins to coat eggshells to reduce post-washing microbial contamination, minimize breakage, and to increase egg shelf-life. Although it is thought most Salmonella enteritidis in eggs occurs by transovarian transmission, it is probable some cases of bacterial contamination of eggs occur by bacteria passing through the eggshell into the egg. The objective was to evaluate edible coatings applied to post-washed eggs as a means to reduce post-wash bacterial contamination, increase structural strength of eggs to reduce breakage, and increase shelf-life of eggs by increasing the barrier to oxygen transmission into eggs. Eggs were divided into 4 groups and coated as follows: eggs unwashed, eggs washed, eggs washed and coated with mineral oil, and eggs washed and coated with soy protein coatings. All groups of eggs were stored at 4C and tested shelf-life, shell egg breakage, and bacterial penetration test using blue lake dye. Egg shell samples from each group was prepared for scanning electron microscopy to examine microstructural changes occurring in shell after washing, coating, and storage. Puncture strength (PS) of coated eggs had higher values than control. Hunter L, a, and b color values and total color differences for soy protein coated eggs were evaluated. Eggs coated with 5% soy protein were generally smoother and shinier than control. Penetration was detected by counting the blue dots on shell membranes after breaking the eggs. All groups except group 3 showed blue dots even at 2min incubation. Group 2 allowed much less penetration, while group 3 allowed the easiest penetration. The effect of oxygen and moisture barrier properties of soy protein film could be an ideal one for testing its application to extend the shelf life of egg quality. In addition, reducing post-wash bacterial contamination would increase consumers confidence in eggs as wholesome safe products.
Session 100B, Food Packaging
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