关键词: 皮蛋, 锌, 物性, NaOH含量, pH值

Abstract: The purpose of this work was to evaluate the availability of zinc sulfate, zinc lactate, zinc chloride, zinc acetate, zinc gluconate and zinc oxide as respective substitutes for lead oxide in preserved eggs. Changes in curing solution alkalinity, pH of whole preserved eggs and texture parameters of preserved egg white and yolk were analyzed during the curing of preserved eggs, and the maturity of preserved eggs was also observed. In general, curing solution alkalinity showed a downward trend during the curing process regardless of which of the six zinc salts was used. Further, the decrease in curing solution alkalinity was gradually attenuated as the curing proceeded, suggesting that these zinc salts can prevent penetration of egg contents. pH of whole preserved eggs presented a trend to first increase and then decrease when zinc oxide, zinc sulfate and zinc gluconate were used, and an increase-decrease-increase trend was observed for preserved eggs cured with zinc lactate or lead oxide. Moreover, the six zinc salts investigated provided preserved eggs with a much higher pH as compared to lead oxide, demonstrating that lead oxide has stronger ability to prevent sodium hydroxide from penetrating into eggs. Preserved egg white and yolk displayed different changes in their harness, adhesiveness, springiness, cohesiveness, chewiness and resilience. From the results of actual observations, it could be concluded that despite having good effectiveness, curing with lead oxide is time-consuming and that zinc lactate, zinc sulfate and zinc acetate not only result in good curing effectiveness but are time-saving as well.

Key words: preserved eggs, zinc, texture properties, sodium hydroxide content, pH value