Study On Process Optimization And Quality Characteristics Of Salt Preserved Egg(SP Egg)

Guang’an salt preserved egg(SP egg) is a specialty-product in Sichuan Guang’an, and favored by consumers because of its delicious taste and characteristics in both salt and preserved eggs. However, the processing problems recently, such as unstable pickling formula, imprecise technology parameters, halfway sterilization, short shelf life and single variety, prevent its development with less study on its processing. In this dissertation, the pickling formula was optimized, quality characteristics of SP eggs in various process stages were discussed, SP egg rich in selenium was developed and shelf life was lengthened by research on sterilization and storage properties. It could provide data foundation and theoretical guide to SP eggs’industrial production. The main conclusions are as follows:(1) The pickling formula was optimized by single factor and orthogonal experiments: the best parameters are10%salt,4%NaOH and0.5%CUSO4. The rest of pickling solution was withdrawal utilized. The results show that less impact between SP eggs dealed by withdraw and mother pickling solution.(2) Quality characteristics of SP eggs(green and white shells) in the different stages of processing were studied. The results showed that from fresh, semi-produced to produced eggs, the value of pH, salt content, alkalinity, ash content increased significantly; moisture generally decreased; TVBN value generally increased;selenium and lead content stayed quite same. The change of pH has particular correlation with the processing. The change of alkalinity value has certain correlation with the processing and the type of eggs. No correlations were found among changes of moisture, ash, salt, TVBN value, selenium, lead content and the processing as well as the type of eggs.(3) There are65,82and68volatile flavor compounds were detected from fresh, From semi-produced and produced eggs. The mostly types are alcohols, hydrocarbons, esters, acids, benzene, ketones, aldehydes and other categories:the content of alcohols, hydrocarbons, esters, benzene and other classes are relatively higher.There are37kinds of the same substances among these three kinds:6alcohols,12hydrocarbons,3esters, acids, benzene and ketones,2aldehydes,5other categories. From fresh to produced egg, amino acid in egg protein and yolk enhance overall; among that, aspartic acid, glutamic acid, serine, leucine are the main substances.(4) Exogenous selenium(sodium selenite) was added in SP egg to study on the influence of different additive contents on the products’pH, alkalinity, salt, Se and Pb content. The results showed that the addition of selenium has little effect on pH, alkalinity, salt content and Pb content value, while has relatively great impact on the Se content. The product’s quality changes in this process have nothing to do with the egg type and processing. The best selenium addition is600mg/L.(5) The sterilization conditions and storage properties of the finished SP egg were studied. The results showed that,115℃,15min and anti-pressure sterilization condition are the best conditions. And SP eggs made by vacuum packaging and anti-pressure sterilization have a good storage performance with8-months shelf life.