纳米TiO2保鲜液对冬枣烂果病及生理品质的影响

纳米材料抗菌防腐作用已在很多领域广泛应用，但由于粒子聚集作用，其抑菌性难以充分发挥。纳米粒子与高分子材料复合可在一定程度上阻止纳米颗粒的聚集，所以将纳米材料复合成高分子复合体应用于农产品防腐保鲜领域将有广泛前景。该研究利用组织分离法从冬枣果实上分离得到了病原真菌，并应用科赫法则验证了其致病性，以羧甲基纤维素钠为基质混合纳米TiO2配成复合保鲜液，对分离得到的致病菌进行了平板抑菌实验，并初步探索了其抑制机理。结果表明，分离得到的冬枣果实致腐菌为半知菌亚门镰孢菌属（Fusarium sp.）真菌，离体实验表明纳米TiO2复合保鲜液对镰孢菌生长有抑制作用，对病原孢子的最低抑菌质量浓度和最低杀菌质量浓度分别为9.77×10-3 g/L和39.06×10-3 g/L，纳米TiO2保鲜液主要通过破坏真菌细胞膜来抑制病原菌的生长；冬枣保鲜研究证实，保鲜液明显降低果实腐烂率并延缓了果实Vc含量的降低。综上，纳米TiO2与CMC-Na复合液可以作为一种有效的抑菌手段应用于采后枣果的镰孢菌防治，为延长冬枣果实保鲜期提供有效的技术支撑。

Effects of Nano-TiO2 Preservation Solution on Fruit Rot Disease and Physiological Quality of Dongzao Jujube

Nanomaterials have been widely used in many fields for their antibacterial and antiseptic effects, but their antibacterial properties can not be brought into full play due to the aggregation of particles. The composite of nanoparticles and polymer materials can prevent the aggregation of nanoparticles to a certain extent, so turning nanomaterials into polymer composites for the applications in the field of antisepsis and preservation of agricultural products will have a broad prospect. In this study, pathogenic fungi were isolated from Dongzao jujube by the tissue isolation method, and their pathogenicity was verified by the Koch''s law. The compound preservative was prepared by mixing nano-TiO2 with the substrate, sodium carboxymethyl cellulose. The plate bacteriostasis experiment was carried out on the isolated pathogenic bacteria, and the inhibition mechanism was preliminarily explored. The results showed that the isolated Dongzao jujube fruit rot was Fusarium sp. In vitro experiments showed that the nano-TiO2 compound preservative solution inhibited the growth of Fusarium sp. The minimum inhibitory concentration and minimum bactericidal concentration on pathogenic spores were 9.77×10-3 g/L and 39.06×10-3 g/L respectively. The nano-TiO2 preservative solution inhibited the growth of pathogen mainly by destroying the fungal cell membrane; the research on the preservation of Dongzhao jujube confirmed that the preservative solution can significantly reduce the rate of fruit rot and delay the reduction of the Vc content in the fruit. In conclusion, the composite solution of nano-TiO2 and CMC-Na can be used as an effective antibacterial means to control Fusarium in the postharvest jujube fruits, which provides effective technical support for prolonging the shelf-life of dongzao jujube.