纳米包装材料对生菜保鲜品质的影响

Effect of Nano-Packaging Material on Quality Preservation of Lettuce (Lactuca sativa)

制备一种含纳米银、纳米TiO2和高岭土的食品用纳米包装材料,研究该材料在生菜贮藏过程中的保鲜效果。对纳米膜进行结构表征及物理特性检测。并检测贮藏过程中生菜质量损失率、叶绿素、VC、多酚氧化酶活性、丙二醛含量等指标变化。研究结果表明:纳米粒子均匀分布在包装材料中,与普通包装材料相比,纵向拉伸强度增加31.69%,透湿量和透氧量降低28.07%和2.10%;4℃、贮藏14d,纳米包装处理的生菜质量损失率、丙二醛含量、多酚氧化酶比活力分别为1.35%、23.01nmol/g、5.43U/g,显著低于普通包装2.75%、26.35nmol/g(P<0.05)、7.63U/g(P<0.01),VC和叶绿素含量显著高于对照组。纳米包装材料较好地保持生菜在贮藏过程中感官品质和营养成分,延长贮藏时间。

A nano-packaging material was prepared by blending polyethylene （PE） with nano-Ag, nano-TiO2 and kaolin, structurally characterized and analyzed for physical properties. Its effect on quality preservation of lettuce was investigated by periodically measuring the changes of weight loss rate, chlorophyll, vitamin C and MDA contents, and polyphenol oxidase （PPO） activity during refrigerated storage. It was observed that nano-particles were evenly distributed in the composite material. Compared with ordinary PE material, it showed an increase in tensile strength of 31.69%, a decrease in water vapor permeability of 28.07%, and a decrease in oxygen permeability of 2.10%. After 14 d of storage at 4 ℃, the weight loss rate, MDA content and PPO activity of lettuce packaged with the nano-material were 1.35%, 23.01 nmol/g and 5.43 U/g, respectively, which were those from ordinary PE packaging （2.75%, 26.35 nmol/g and 7.63 U/g, respectively）, while the nano-material resulted in significantly increased VC and chlorophyll contents in lettuce in comparison with the control （ordinary PE material）. This composite material could better maintain the sensory quality and nutrients of lettuce during cold storage and consequently extend its shelf life.