摘要：In our previous paper, we reported a phenomenon that adipate (AAE) utilized as the plasticizer for polyvinyl chloride cling films was hydrolyzed to alcohols and adipic acid when they were kept in contact with non-cooked foods. In this paper, the decomposition of adipates by fresh vegetables was investigated using di-2-ethylhexyl adipate (DEHA) and diisononyl adipate. AAE added to various fresh vegetables was decomposed after incubating at 35°C for 1 h to yield alcohols, which were undetected in the original vegetables. In the cases of fruit, cucumbers, tomatos and red peppers, it was found that the rate of the decomposion of AAE decreased as they were ripening. The AAE hydrolyzing component in cucumbers was extracted with 50 mM Tris-HCl buffer (pH 7.5) and only when 1% triton X-100 was added to the buffer the extraction was most efficient. The AAE decomposing activities of the extract showed the best result under the conditions of pH 7-7.5 and 35°C and were lost in the case of heating at 100°C for 5 min. This suggests that the decomposition of AAE is an enzymatic hydrolysis reaction. Other aliphatic dicarboxylic acid esters such as DEHA, di-2-ethylhexyl azelate, di-2-ethylhexyl sebacate and di-2-ethylhexyl dodecanediocate were also hydrolyzed by the cucumber extract, but as the carbon number of these acids increases, the rate of hydrolysis diminished. The molecular weight of the putative enzyme in the cucumber extract catalyzing the hydrolysis of AAE was estimated to be 25000-45000 by gel filtration chromatography on Sephadex G-100.
