Method for Recovering Preservatives in Foods by Steam Distillation under Reduced Pressure

Abstract

A method for recovering preservatives in foods by the steam distillation under reduced pressure was studied. The outline of procedure is as follows.
1) In the case of samples containing dehydroacetic acid (DHA), sorbic acid (SOA), benzoic acid (BA) and salicylic acid (SA), the distillation was conducted under 90mmHg of pressure and at 50°C (water bath temperature: about 70°C), after addition of a 10ml of portion of 10% citric acid, suitable amouts of water, 20g of NaCl and 50g of MgSO₄·7H₂O, and adjusting pH to 2.0-2.5. 240ml of distillate was retained.
2) In the case of samples containing butyl p-hydroxy-hydroxy benzoate (POBA-Bu), the distillation was carried out at about 80°C (water bath temperature: about 95°C), and under the same low pressure, after addition of suitable amouts of water, 20g of NaCl, and adjusting pH to 3.0, and then 490ml of distillate was obtained.
By the application of this method, the preservatives in foods could be recovered rapidly, and sucrose, in particular, among other ingredients in foods were almost never decomposed during the process.