Optimization of extraction of paralytic shellfish poisoning from Alexandrium minimum by melting-freezing method

To enhance the broken rate of Alexandrium minimum，to keep the composition unchanged and the toxicity of Paralytic Shellfish Poisoning（PSP）in the extraction process，the freezing-melting extraction method for PSP was used in this paper. Firstly，five single factor experiments were conducted to study the effects of pH，freezing temperature，melting temperature，freezing time and melting times on broken rate and relative fluorescence value， respectively. Then Box-Behnken response surface optimization was used to obtain the optimum conditions，with the relative fluorescence value as response value. The results showed that，the optimum conditions for extraction of PSP by melting-freezing method were as follows：pH 7.66，melting times of 3.45，at 36.99℃. Under these conditions， the relative fluorescence value and virulence were 200.347，7 034 MU，respectively. In the verified experiment， the conditions for PSP extraction from A. minimum were：pH 7.8，melting times of 3，at 37℃，under these conditions，the relative fluorescence value and virulence were 188.923（±10.96），6 616（±101）MU， respectively