纳米TiO2/PE保鲜膜的研制及其在香菇保鲜中的应用

摘  要

本文以LDPE为基材，选择具有抗菌性能的纳米TiO2为填充料以提高包装材料的抗菌性，制备了不同添加量的纳米TiO2/PE保鲜膜。根据薄膜的拉伸强度、断裂伸长率、透光率、雾度、透氧率和透湿量，分析不同添加量的纳米TiO2对薄膜基本性能的影响。并利用所制抗菌膜对香菇进行自发气调包装，通过测定常温下香菇的呼吸强度、失重率和感官评分，研究不同添加量的纳米TiO2抗菌膜对香菇保鲜效果的影响。
结果表明：由于纳米粒子能在薄膜内部充当交联点的作用，随着纳米TiO2添加量的增加，薄膜的拉伸强度和断裂伸长率逐渐升高；纳米TiO2添加到PE中后，使PE的球晶细化，提高了薄膜的透光率、降低了薄膜的雾度，使薄膜变得更加透明；添加了纳米TiO2的薄膜与空白膜相比，阻隔性能变强，透氧率和透湿量都降低。通过抑菌试验，表明纳米TiO2对常见细菌、霉菌及酵母菌均有较好的抑菌性能。对保鲜试验的香菇进行呼吸强度、失重率和感官评分测定，纳米TiO2薄膜对香菇的保鲜效果优于空白膜和未包装的对照组。其中，以添加量为0.5%的薄膜包装的香菇的保鲜效果最好，其包装的香菇的呼吸高峰出现最晚且呼吸峰值最低(332.9ml/kg•h)，第8天的失重率仅为3.9%，常温下可保鲜7天，比未包装的对照组延长了5天。

关键词：保鲜膜，气调包装，纳米TiO2，香菇

ABSTRACT

In this paper, LDPE material was used as a substrate and the Nano-TiO2 as filler to enhance the antimicrobial of packaging materials. Various properties of fresh-keeping films were examined, such as tensile strength, elongation at break, transparence, haze, manometric gas permeability and vapor permeability. The films with Nano-TiO2 were used to package mushroom for examining fresh-keeping performance. The respiration rate, percentage of losing-weight and organoleptic test of the mushroom were examined, which were used to study the effect of the film on mushroom.
The results showed that as the amounts of Nano-TiO2 increased, the tensile strength and the elongation at break of the films have increased gradually; As the amounts of Nano-TiO2 increased, films have become more transparent; As the amounts of Nano-TiO2 increased, the gas permeation rate and vapor permeation of the films reduced gradually. Nano-TiO2 all showed antibacterial effect to different animalcule. By testing the respiration rate, percentage of losing-weight and organoleptic test of the mushroom, it was indicated that the film with Nano-TiO2 preservation of the mushroom was better than pure PE film and CK. The respiration peak of mushroom packed with filled film with 0.5% Nano-TiO2, appeared latest the peak value was lowest at 332.9 ml/kg•h, And 8 days later the percentage of losing-weight of mushroom with packing amounts to 3.9%, the mushroom under the normal temperature can protect for fresh 7 days, which was 5 days longer than the group without packing.

Keywords: Fresh-keeping film, Modified Atmosphere Packaging, Nano-TiO2, Mushroom

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