食品接触用生物降解塑料购物袋材质鉴别与总迁移量研究

采用红外光谱仪（FTIR）对市售的6种食品接触用生物降解塑料购物袋（1^#~6^#）材质进行鉴别，测试了其在不同浸泡条件下的总迁移量，并对部分样品的蒸发残渣成分进行了表征。结果表明，2^#与4^#样品材质定性结果与其标注材质不一致；生物降解塑料购物袋总迁移量远大于传统聚乙烯（PE）塑料购物袋，2^#~6^#样品在4 %（体积分数，下同）乙酸模拟液中浸泡及1^#~6^#样品在95 %乙醇模拟液中浸泡时的总迁移量均超过限量要求（10 mg/dm²），说明生物降解塑料购物袋直接接触食品存在一定食品安全风险；样品中的PBAT能在95 %乙醇中溶解；样品中掺杂的CaCO₃在4 %乙酸模拟液中出现了大量迁移，这是由于CaCO₃本体发生迁移及CaCO₃与乙酸发生反应生成了乙酸钙；淀粉（ST）颗粒在水中会发生糊化脱落，而乙酸进入ST颗粒中会破坏ST的分子结构，导致掺杂ST的生物降解塑料购物袋总迁移量显著增大。

Study on material identification and total migration of biodegradable plastic shopping bags used for food contact

The materials obtained from six types of commercially available biodegradable plastic shopping bags （samples 1^#~6^#） for food contact were identified by an infrared spectrometer， their total migration amounts were measured under different soaking conditions， and the evaporation residue components of some samples were investigated. The results showed that the qualitative results of the materials from the bag samples 2^# and 4^# were inconsistent with those as the materials marked. The total migration amount of the biodegradable plastic shopping bags was much greater than that of the traditional polyethylene plastic shopping bags. The total migration results of the 2^#~6^# samples exceeded the required limit （10 mg/dm²） when immersed in 4 vol% acetic acid simulation solution. So did the samples 1^#~6^# when immersed in 95 vol% ethanol simulant solution. This indicates that there was a certain food safety risk when biodegradable plastic shopping bags were directly used for food contact. The PBAT in the bag samples could be dissolved in 95 vol% ethanol. The CaCO₃ in the samples presented a large migration amount in the 4 vol% acetic acid simulation solution， which was attributed to the migration mass of CaCO₃ as well as the calcium acetate formed by the reaction between CaCO₃ and acetic acid. Starch particles could gelatinize and fall off in the water， and acetic acid could enter the starch particles to destroy the molecular structure of starch， resulting in a significant increase in the total migration of biodegradable plastic shopping bags compounded with starch.