稀土镧掺杂纳米二氧化钛复合保鲜包装薄膜的研究

Composite Films Contained Rare Earth Lanthanum Doped Nano TiO2 as Efficient Materials for Packaging Preservation

中文关键词: 稀土镧 纳米二氧化钛 复合包装薄膜 阻隔性能 保鲜性能

英文关键词: rare earth lanthanum, nano-titanium dioxide, packaging composite film, barrier property, preservation perfor-mance

中文摘要:

      水果和菌类均为货架期较短的商品,二者皆易因呼吸作用与微生物感染导致失水与腐坏。本工作首次报道了将稀土镧掺杂纳米TiO₂(La³⁺-TiO₂)粒子与PVA共混,采用溶液浇铸法制备了La³⁺-TiO₂复合包装薄膜,并将其用于草莓和姬松茸保鲜的探索研究。XRD、SEM和LPSA表征显示,稀土镧的掺杂引起了纳米TiO₂晶格的畸变,其粒径变小、表面能增大,掺杂后的纳米TiO₂在PVA基体中的分散性得到提高。透湿和透氧率检测结果表明,La³⁺-TiO₂的加入有利于复合薄膜阻隔性能的增加,当La³⁺-TiO₂质量分数为1.6%时,透湿率降低45.9%,透氧率降低38.0%,复合薄膜阻隔性能最佳。抗菌率检测结果显示,稀土镧的掺杂拓宽了TiO₂对光谱的利用范围,复合包装薄膜在自然光下对大肠杆菌和金黄葡萄球菌的杀灭率分别达到84.1%和91.8%。保鲜实验结果表明,复合包装薄膜因其优良的阻隔性和抗菌性,有效抑制了草莓贮存过程中的果实腐坏和质量损失,常温下将草莓的保质期从5 d延长至10 d左右；同时复合薄膜可减缓姬松茸贮藏过程中的自溶和褐变等现象,常温下将姬松茸的保质期从2 d延长至4 d左右,其包装保鲜效果良好。

英文摘要:

      Fruits and fungus are short-shelf life products which are easily decaying caused by micro-organism and dehydration caused by respiration. This paper presented a pioneering attempt to prepare PVA-based packaging composite films contained lanthanum doped nano-TiO₂ (La³⁺-TiO₂) and to apply it as preservation material for strawberry and agaricus blazei. Characterizations of La³⁺-TiO₂ were done by XRD, SEM and LPSA. The distortion occurred in lattice of TiO₂ and led the particle size reduced, surface energy increased and dispersity in PVA matrix improved due to the doping of La³⁺. Barrier performance of the composite films were improved by adding La³⁺-TiO₂, and it was revealed that the composite films obtained the optimal barrier performance when mass fraction of La³⁺-TiO₂ reached 1.6%. The water vapor permeability and oxygen permeability were decreased by 45.9% and 38.0%, respectively. Results of antibacterial tests showed that spectrum utilization range of nano-TiO₂ had widened by La³⁺ doping, so that the antibacterial rate of the composite films against E. coli. and S. aureus were respectively beyond 84.1% and 91.8% in natural light. The strawberries were well preserved for 10 d at room temperature by the composite films, the rotted rate and weight loss rate were both controlled below 5%. The shelf life of agaricus blazei was also extended from 2 d to 5 d at room temperature, due to the composite films slowed down the browning, autolysis and other phenomena during the storage of agaricus blazei.