聚乳酸薄膜处理对黄花菜保鲜效果分析

Application of polylactic acid film packaging to daylily flower preservation

聚乳酸(PLA)是一种完全生物降解材料,为研究PLA薄膜对黄花菜的保鲜效果,以聚乙烯(PE)薄膜为对照,用不同厚度PLA薄膜对黄花菜进行了气调保鲜处理,在(25±1)℃贮藏期间对黄花菜的相关品质指标进行了测定。结果表明,PLA薄膜O_2和CO_2透过率低于PE薄膜,贮藏期间形成低氧高二氧化碳气体环境,抑制黄花菜呼吸作用,可明显减缓可溶性蛋白质、可溶性糖、叶绿素和抗坏血酸(Vc)含量的下降,抑制细胞膜渗透率、过氧化物酶(POD)活性的上升,延长黄花菜的贮藏保鲜期至10 d,而PE薄膜仅能贮藏6 d,厚度25μm的PLA薄膜保鲜效果最好。

Polylactic acid is a biodegradable material. In order to explore the effect of polylactic acid （PLA） film on fresh keeping of daylily flowers, an experiment was carried to determine if the PLA film thickness affected the preservation effect of daylily flowers with the polyethylene （PE） film as a control. The relevant quality indexes of daylily flowers were periodically recorded at （25±1）℃. The results showed that a gas condition with less oxygen and more carbon dioxide was formed inside the PLA film due to its lower O2 and CO2 penetration rate compared to the PE film. Such a gas condition inhibited the respiration of daylily flowers and obviously slowed the declining of soluble protein, soluble sugar, chlorophyll and ascorbic acid （Vc） contents in daylily flowers. The gas condition also inhibited the rising of permeability of cell-membrane and peroxidase （POD） activity during a storage period, which obviously prolonged the daylily flower storage time to 12 d , longer than 9 d of PE films. PLA film with 25 μm thickness showed the best preservation result.