Study on technology of removing heavy metals from east sea cucumber (Acaudina leucoprocta)

The east sea cucumber is an abundant species of the family Holothuroidea with high nutritive value. However, it can't be utilized because its body wall contains a large amount of heavy metals. To develop a method for desorption of heavy metals, the distribution of heavy metals in the east sea cucumber was firstly investigated. Then, chemical method and chemo-enzymatic method were used to remove the heavy metals. The conditions including the soaking reagent and temperature, enzyme type and amount, treating time by chemical method and chemo-enzymatic method were optimized. The results showed that the chemo-enzymatic method exhibits better result both in appearance quality and removing rate than chemical method. The optimal conditions of chemo-enzymatic method for desorption of heavy metals were as followings: enzymmatic hydrolysis at 37℃ for an hour with papain (0.10%, w/w) , then, being soaked with citric acid (2.0%, w/v) for 48 hour. Under these conditions, 90% of heavy metals in the east sea cucumber were removed.