title: Effect of basic alkali-pickling conditions on the production of lysinoalanine in preserved eggs.
abstract: During the pickling process, strong alkali causes significant lysinoalanine (LAL) formation in preserved eggs, which may reduce the nutritional value of the proteins and result in a potential hazard to human health. In this study, the impacts of the alkali treatment conditions on the production of LAL in preserved eggs were investigated. Preserved eggs were prepared using different times and temperatures, and alkali-pickling solutions with different types and concentrations of alkali and metal salts, and the corresponding LAL contents were measured. The results showed the following: during the pickling period of the preserved egg, the content of LAL in the egg white first rapidly increased and then slowly increased; the content of LAL in the egg yolk continued to increase significantly. During the aging period, the levels of LAL in both egg white and egg yolk slowly increased. The amounts of LAL in the preserved eggs were not significantly different at temperatures between 20 and 25ºC. At higher pickling temperatures, the LAL content in the preserved eggs increased. With the increase of alkali concentration in the alkali-pickling solution, the LAL content in the egg white and egg yolk showed an overall trend of an initial increase followed by a slight decrease. The content of LAL produced in preserved eggs treated with KOH was lower than in those treated with NaOH. NaCl and KCl produced no significant effects on the production of LAL in the preserved eggs. With increasing amounts of heavy metal salts, the LAL content in the preserved eggs first decreased and then increased. The LAL content generated in the CuSO4 group was lower than that in either the ZnSO4 or PbO groups.
authors.affiliation: Jiangxi Key Laboratory of Natural Products and Functional Food, Jiangxi Agricultural University, Nanchang 330045, China Engineering Research Center of Biomass Conversion, Ministry of Education, Nanchang University, Nanchang 330047, China State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Engineering Research Center of Biomass Conversion, Ministry of Education, Nanchang University, Nanchang 330047, China State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China.
authors.forename: Xuying
authors.initials: X
authors.lastname: Luo
authors.affiliation: Engineering Research Center of Biomass Conversion, Ministry of Education, Nanchang University, Nanchang 330047, China State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China.
authors.forename: Jianke
authors.initials: J
authors.lastname: Li
authors.affiliation: Jiangxi Key Laboratory of Natural Products and Functional Food, Jiangxi Agricultural University, Nanchang 330045, China.
authors.forename: Mingsheng
authors.initials: M
authors.lastname: Xu
authors.affiliation: Jiangxi Key Laboratory of Natural Products and Functional Food, Jiangxi Agricultural University, Nanchang 330045, China tygzy1212@aliyun.com.
authors.forename: Yonggang
authors.initials: Y
authors.lastname: Tu
mesh_terms: D000468:Alkalies / Q000737:chemistry*; D000818:Animals; D004372:Ducks; D004529:Egg White / Q000737:chemistry*; D004530:Egg Yolk / Q000737:chemistry*; D005519:Food Preservation; D008241:Lysinoalanine / Q000032:analysis*
chemical_list: D000468:Alkalies; D008241:Lysinoalanine
keywords: alkali-pickling condition; lysinoalanine; metal ions; preserved egg