CuZnAl-MMO复合纳米抗菌薄膜对樱桃保鲜效果的影响

Effect of CuZnAl-MMO Composite Antimicrobial Nanofilms on Cherry Preservation

摘要:

樱桃采后易腐烂且易被微生物感染,而传统保鲜方法具有潜在毒性和化学残留等缺点。为了解决这一问题,采取有机无机杂化策略,构建由CuZnAl复合金属氧化物(CuZnAl-MMO)纳米粒子增强的壳聚糖(CS)和聚乙烯醇(PVA)的复合纳米薄膜。通过分析纳米薄膜的形态结构、力学性能、疏水性能和阻隔性能,证明了CuZnAl-MMO与CS/PVA发生了自组装,增强了纳米薄膜的力学性能和疏水性。相较于CS/PVA-0% MMO纳米薄膜,CS/PVA-6% MMO纳米薄膜的拉伸强度增加了35%,接触角从43.4°上升到了67.9°。此外,CS/PVA-6% MMO纳米薄膜的水蒸气透过率和氧气透过率比CS/PVA-0% MMO纳米薄膜分别下降了43.2%和80.3%。这是由于自组装过程导致了薄膜内碳链通道的重组,从而提高了阻隔性能。这种重组促进了有利于樱桃储存的微环境的形成,既提高了纳米薄膜的防潮性,又促进了气体改良气氛的形成。研究发现,随着CuZnAl-MMO在纳米薄膜中含量的逐渐增加,纳米薄膜对革兰氏阴性菌大肠杆菌、革兰氏阳性菌金黄色葡萄球菌和灰霉菌的抗菌性能逐渐增强。樱桃保鲜实验结果显示,纳米薄膜能够显著降低坏果率、失重率以及樱桃表面的总菌落数,同时延缓了硬度的下降。纳米薄膜还改善了樱桃的呼吸频率,使得包装袋内的CO₂体积分数升高至16.1%。在纳米薄膜内成功促进气体改良气氛形成对樱桃的保存非常有利。CuZnAl-MMO复合纳米薄膜对微生物的抑制效果和对樱桃保鲜性能的提升表明,这种新型保鲜方法具有一定的应用前景。研究旨在为CuZnAl-MMO复合纳米薄膜在果蔬保鲜领域的应用提供一定的理论基础。

Abstract:

In post-harvest processing, cherries face challenges such as decay and microbial infections. Traditional preservation methods pose potential toxicity and chemical residue issues. To address these issues, an organic-inorganic hybrid strategy was employed to construct a nanofilm composed of chitosan (CS) and polyvinyl alcohol (PVA) reinforced with CuZnAl-MMO nanoparticles. Through analyzing the morphology, mechanical properties, hydrophobicity, and barrier performance of nanofilms, the self-assembly of CuZnAl-MMO with CS/PVA was demonstrated, resulting in enhanced mechanical strength and hydrophobicity of nanofilm. Especially, compared to CS/PVA-0% MMO nanofilm, the tensile strength of CS/PVA-6% MMO nanofilm was mildly enhanced by 35%, and the contact angle was increased from 43.4° to 67.9°. Additionally, the water vapor transmission rate and oxygen transmission rate of CS/PVA-6% MMO nanofilm decreased by 43.2% and 80.3%, respectively, compared to CS/PVA-0% MMO nanofilm. This was attributed to the self-assembly process, leading to the reorganization of carbon chain channels within the film, thereby enhancing barrier performance. This restructuring facilitated the creation of a microenvironment conducive to cherry storage, enhancing both moisture resistance of the nanofilms and the development of a gas-modified atmosphere.The study revealed that as the content of CuZnAl-MMO in the nanofilm gradually increased, the antimicrobial properties of nanofilms against Gram-negative bacteria (E.coli), Gram-positive bacteria (S.aureus), and gray mold fungus sequentially strengthened. Furthermore, results from the cherry preservation experiment indicated that the nanofilm significantly reduced the rate of decay, weight loss, and the total bacterial count on the surface of cherries, while also slowed down the decrease in hardness. The nanofilm improved the respiration rate of cherries, leading to a rise in CO₂ concentration to 16.1% within the packaging bag. The successful promotion of gas-modified atmosphere within the nanofilm proved advantageous for cherry preservation. In conclusion, the inhibitory effects of CuZnAl-MMO nanofilm on microorganisms and the enhancement of cherry preservation performance suggested that this novel preservation method had certain application prospects. The research aimed to provide theoretical basis for the application of CuZnAl-MMO composite antimicrobial nanofilms in the field of fruit and vegetable preservation.