不同阻隔性包装材料对生菜保鲜效果的影响

Effects of different barrier packaging materials on preservation of lettuce

为了研究不同阻隔性包装材料对采后生菜保鲜效果的影响,选择低密度聚乙烯膜(LDPE)、聚乙烯膜(PE)、高密度聚乙烯膜(HDPE)、乙烯—乙烯醇共聚物/聚乙烯复合膜(EVOH/PE)4种包装材料对生菜进行气调包装,并设置无包装组作为对照,置于4℃的冷库中贮藏。贮藏期间,定期对各组生菜感官、失重率、叶绿素含量、相对电导率以及袋内气体组分等指标进行测定。结果表明,第6天时,对照组生菜因失水严重而失去商品价值;EVOH/PE组中O_2即将耗尽,CO_2比例达到20.3%,袋内出现酒精气味;其它3组袋内O_2比例均先降低,在小范围内呈波动性变化,CO_2比例先升高后相对平稳。HDPE组贮藏时间达18d,保鲜效果最好。阻隔性适宜的包装材料可以有效提高生菜的保鲜效果,延长保鲜期。

In order to investigate the effect of different barrier packaging materials on the preservation of harvested lettuce. Lettuces were encased in modified atmosphere packaging （MAP） with LDPE, PE, HDPE and EVOH/PE films and stored at 4℃, while the ones with- out packaging were used for comparison under the same conditions. During storage, the gas composition in packaging, sensory quality, weight loss, chlorophyll content and relative conductivity of lettuces were measured regularly. On the sixth day, lettuces in the control group lost the commodity value due to serious water loss. In the EVOH/PE group, O2 was running out and the CO2 ratio reached 20.3%. It also produced an alcohol smell in the bag. The O2 ratio in the other three groups decreased first, then fluctuated within a small range, and the proportion of CO2 increased first and then relatively stable. The preservation effect of HDPE group was the best, and the storage time could reach 18 days. Barrier suitable packaging materials could effectively improve the preservation effect of lettuce, therefore their shelf life was extended.