用于食品保鲜包装的聚乳酸透气膜研究

Study on Polylactic Acid Breathable Film for Food Preservation Packaging

制备了聚乳酸透气膜,并研究了其用于猪肉包装的保鲜效果.采用非溶剂致相分离法制备聚乳酸膜,通过添加N-甲基吡咯烷酮,使得薄膜具备多孔结构.对薄膜的透光率进行了测试,利用扫描电镜和红外光谱仪对薄膜的微观结构和基团组成进行了表征.实验发现,聚乳酸多孔膜扫描电镜图与聚乳酸纯膜相比,薄膜内部具有均匀的多孔结构.从红外光谱图中可以看出,添加了N-甲基吡咯烷酮的薄膜与聚乳酸纯膜的吸收峰没有明显的差别,说明N-甲基吡咯烷酮在后续操作中从薄膜中分离出来,形成孔洞后并不会影响聚乳酸膜本身结构.在薄膜用于新鲜猪肉的包装中,通过聚乳酸透气膜的包装,猪肉的保质期得到了延长.与保鲜袋、保鲜膜、聚乳酸纯膜包装的猪肉相比,聚乳酸透气膜能有效延长猪肉保质期2~3 d.

Polylactic acid(PLA)breathable film was prepared and its preservation effect on pork was also studied.PLA film was prepared by non-solvent induced phase separation(NIPS)and porous structures were obtained by adding n-methylpyrrolidone(NMP).The transmittance of the film was tested and the microstructure and the group composition of the film were characterized by SEM and FTIR.It was found that the PLA porous film showed uniform porous structure compared with the pure PLA film through scanning electron microscopy.It can be seen from the infrared spectrum that the absorption peak of the film with NMP added is not significantly different from that of the pure film of PLA,indicating that NMP can be completely dissolved in water and separated from the film when soaked in water.Besides,the porous structure does not affect the PLA film at all.In the film packaging of fresh pork,the shelf life of the pork is extended by using breathable film.Compared with the pork wrapped in plastic bags,plastic film and pure PLA film,breathable film can effectively extend the shelf life of pork by 2-3 days.