New Egg Preservative Coating Preparation And Storage Of The Screening Study

In this paper, the extracts of natural herbs as raw material, were used to investigate their bacteriostatic effects on the common pathogenic bacterias of eggs, in addition, common cooking oil and edible materials as the carrier were prepared two types of coating preservative——oil-soluble and emulsified. Through the sabotage experiment under the condition of high temperature and humidity, the best coating preservative of the two types was selected settingout the internal quality changes over time. Finally, the selected preservation were determined under room temperature for fresh test, measuring the physical and chemical indicators variation of eggs over time, and analyzing its effect of egg preservation. The main results were summarized as follows;(1) Bacteriostatic experiment of extracts of natural herbs on common pathogenic bacterias of eggs. Selecting from eugenol, cubeba oil, oregano oil, houttuynia oil, artemisia vulgaris oil and mint oil on the basis of their bacteriostasic activity of Escherichia coli, Staphyloccocus aureus and Salmonella, cubeba oil, oregano oil and mint oil were chose as the best bacteriostats to carry out the orthogonal test. As a result, the complex natural antibacterial agent was compose of 0.5mg/ml oregano oil, 0.5mg/ml cubeba oil and 0.7mg/ml mint oil.(2) The preparation of oil-soluble and emulsified coating preservative using the common cooking oil(soya bean oil, palm oil(12degree), rapeseed oil and peanut oil) and edible material as carrier, supplemented with complex antibacterial agent, ETo prepare the oil-soluble coating preservative with additional antioxidants (VE and citric acid). Under the condition of 60℃and 10d storage, the best formula was determined by measuring the peroxide value (POV) and acid value. In consequence, when VE and citric acid were added respectively 0.04% and 0.02%, the oil-soluble coating preservative has the best oxidative stability.To prepare the emulsified coating preservative with film-forming additives (sodium carboxymethyl cellulose-CMC and chitosan) and emulsifier (Span 80, Tween 80 and sucrose ester). The optimization of emulsion technology was emulsifying 2 mins at the speed of 10 OOOr/min with the formula of 0.6% CMC & chitosan,10% oil phase and 3.5% emulsifier.Then, its viscosity, surface tension and emulsion stability were determined and the structure changes of the shell outer surface of coated eggs was characterized by scanning electron microscope.(3) To select the best formulations of oil-soluble and emulsified coating preservative under the storage condition of high temperature and humidity by means of sabotage experiment. Time-varying changes in the internal quality of coated eggs have shown that: the emulsified group and blank control group were significant difference(P≤0.01), especially the CMC group can more effectively prevent the egg internal quality changes; the palm oil group——oil-soluble type significant differ with other groups(P<0.05), best on the inhibitory effect of changes in the internal quality of eggs.(4) Test at room temperature preservation on CMC and palm oil coating preservative. The blank group and the improvement of mineral (add complex bacteriostatic agent) as the control group, deposited at room temperature, from Oct.10,2009 to Mar.10,2010, 150 days in total, tacking monitoring the changes of egg quality varying with time.The results showed that:the difference between the groups was significant (P≤0.01), the weight loss rate of CMC group after 150d was 4.4523%, the mineral oil coating group was 1.5231%, and palm oil coating group is only 1.3751%.