Study On The Processing And Preservation Of Low Sodium Salted Egg

Salted egg is a traditional special egg product in China, and is deeply favored bydomestic and overseas consumers. At present, due to the problems of high salt content,long processing time and short shelf life, the industrial development of salted egg wasseriously affected. In order to reduce the salt content, shorten pickling time, and extendthe shelf life of salted egg, the egg was pickled using the food additive-grade potassiumchloride (KCl) and potassium carbonate (K2CO3) to partly replace sodium chloride(NaCl). The penetration rate of salt was accelerated by the decompression technology,and the mixing fresh-keeping agents, Chitosan, Natamycin, and Nisin, studied in coatingpreservation of salted egg. The results were as follows:1. The effects of curing agent, which was prepared by partly replacing potassiumchloride (KCl) and potassium carbonate (K2CO3) to sodium chloride (NaCl), on thequality of salted egg were researched by orthogonal test. The best ratio for the amount ofNaCl, KCl and K2CO3was19%,4%and1%, respectively. Compared with25%brine,the sodium content of salted egg pickling by the curing agent have a decline of20.19%without any significant difference in quality (P>0.05), and the potassium content wassignificant improved. The changes in chemical (salt content, moisture, pH, and yolkoil-off ratio) and physical (viscosity, texture) properties of salted eggs were investigatedin the process of curing. Result showed that the oil-off ratio and salt content of eggspossessed an upward trend, and the water content and viscosity of salt eggs showed adownward trend during curing. There was a rise in the pH value of salted eggs that waspickled by the curing agent, and control groups had a declined trend.2. By comparing with normal pressure curing, the effect of the vacuum breathcuring (GroupⅠ:maintaining vacuum degree11.5h, breaking vacuum12.5h every day,GroupⅡ:Maintaining vacuum degree23.5h, vacuum breaking vacuum degree0.5h) onthe quality of salted egg was studied. The salt content in salted egg and oil-off ratio ofyolk were determined during the curing process, and sensory evaluation was conductedat the later stage of curing. Results indicated that the salt content and oil yield increasedduring the curing process without any difference in oil-off ratio between vacuum breathcuring for16days (GroupⅡ) and normal pressure curing for22days(P>0.05), nor didthe salt content showed any difference compared with normal pressure curing for26days(P>0.05). Therefore, the vacuum breath curing can shorten the processing time ofsalted egg.3. The effects of Chitosan, Natamycin, and Nisin as a coating agent on the freshnessof salted eggs preserved under high temperature were studied by orthogonal test, and thebest ratio for chitosan, Nisin, natamycin was1%,0.07%and0.06%, respectively. TVB-N and total bacterial population of salted egg coated by this preservative storedunder high temperature after12days were not higher than national standard, suggestingthat the preservative can effectively extend the shelf life of salted egg.