Liao Jing, Wen Ruizhi, Wang Yijin, Zhou Yuhang, Zhang Jiamin
College of Food and Biological Engineering, Chengdu University, Chengdu 610106, China.
Meat Processing Key Laboratory of Sichuan Province, Chengdu University, Chengdu 610106, China.
Biomacromolecules. 2024 Aug 12;25(8):5138-5148. doi: 10.1021/acs.biomac.4c00528. Epub 2024 Jul 15.
Developing sustainable food-active packaging materials is a major issue in food preservation applications. Chitin nanocrystals (ChNCs) are regarded as unique bioderived nanomaterials due to their inherent nitrogen moiety. By tuning the chemical functionality of this nanomaterial, it is possible to affect its properties, such as film-forming capability and antibacterial activity. In this work, surface-deacetylated chitin nanocrystals (D-ChNCs) with different degrees of deacetylation (DDs) were prepared by partial deacetylation of native chitin and subsequent acid hydrolysis, and their film-forming capability and antibacterial activity were studied systematically. The D-ChNCs showed favorable film-forming ability and antibacterial activity, which are closely related to their DD. With the increase in DD (from 5.7% to 45.4%), the formed transparent films based on ChNCs showed gradually increased elongation at break (from 0.5% to 2.5%) and water contact angle (from 25.5° to 87.0°), but decreased break strength (from 3.13 to 0.89 MPa), Young's modulus (from 0.84 to 0.24 MPa), and water vapor permeability (from 4.7 × 10 to 4.1 × 10g/m s Pa). Moreover, the antibacterial activity of the D-ChNCs against and also increased with the increase of DD. This study also found that the depolarization and potential dissipation of the bacterial cell membrane induced by the contact between amino-rich D-ChNCs and bacteria through electrostatic attraction are the possible mechanisms causing bacterial cell death. This study provides a basis for understanding the effects of DD on the film-forming capability and antibacterial activity of ChNCs, which is conducive to the design of novel active packaging films based on ChNCs.
开发可持续的食品活性包装材料是食品保鲜应用中的一个主要问题。由于其固有的含氮部分，几丁质纳米晶体（ChNCs）被视为独特的生物衍生纳米材料。通过调节这种纳米材料的化学功能，可以影响其性能，如成膜能力和抗菌活性。在这项工作中，通过天然几丁质的部分脱乙酰化和随后的酸水解制备了具有不同脱乙酰度（DDs）的表面脱乙酰化几丁质纳米晶体（D-ChNCs），并系统研究了它们的成膜能力和抗菌活性。D-ChNCs表现出良好的成膜能力和抗菌活性，这与它们的DD密切相关。随着DD的增加（从5.7%到45.4%），基于ChNCs形成的透明薄膜的断裂伸长率（从0.5%到2.5%）和水接触角（从25.5°到87.0°）逐渐增加，但断裂强度（从3.13到0.89 MPa）、杨氏模量（从0.84到0.24 MPa）和水蒸气透过率（从4.7×10到4.1×10 g/m s Pa）降低。此外，D-ChNCs对[具体菌种1]和[具体菌种2]的抗菌活性也随着DD的增加而增强。该研究还发现，富含氨基的D-ChNCs与细菌通过静电吸引接触所诱导的细菌细胞膜去极化和电位耗散是导致细菌细胞死亡的可能机制。这项研究为理解DD对ChNCs成膜能力和抗菌活性的影响提供了依据，有助于基于ChNCs设计新型活性包装薄膜。
