Yucheng Zou,Aiping Zhang,Lin Lin,Sobhy Ahmed El-Sohaimy,Yang Li,Liangru Wu,Hui Zhang
Recently, biopolymer-based structured oil has emerged to substitute saturated and trans -fats. Herein, the porous biopolymeric networks with the cellular structure were developed with cross-linked dialdehyde cellulose (DAC) and gelatin to prepare oleogels. The determination of aldehyde content in the DAC molecular chain revealed a high degree of oxidation of cellulose. The FTIR data showed the covalent cross-linking bond between the DAC and gelatin. The covalent cross-linking between DAC and gelatin promoted the composite aerogel (DG) to form a porous three-dimensional network structure with enhanced thermal stability , mechanical properties, and water stability. The DAC/gelatin composite aerogel with 5 wt% DAC (DG-5) exhibited the highest porosity (91.27 %) and lowest pore diameter (10.52 μm) with greater capillary force, resulting in a high oil absorption capacity of 11.24 g/g and oil holding capacity of 55.57 %. The DG oleogels containing 6 % thymol in the oil phase showed good antibacterial activities against Escherichia coli and Staphylococcus aureus for 24 h. This work provides a facile and promising strategy for developing oleogels by DAC/gelatin cross-linked conjugates as aerogel templates for oil structuring.
Yu Ma,Ru Tian,Yudong Song,Chenghui Yin,Hui Huang,Yongxin Li
Pullulan polysaccharide electrospun nanofiber membrane is promising in food packaging field. However, there are still some limitations in its application, due to its high hydrophilicity, poor basic properties (water and thermal stability, mechanical properties, etc.) and weak bioactivity. To solve these problems, pullulan polysaccharide was first oxidized to dialdehyde pullulan polysaccharide (DPul). Then the DPul was prepared into electrospun nanofiber membrane (DPul-M). The DPul-M was used as a green crosslinking agent, and the aldehyde group on the DPul-M and the amino group of lysozyme were reacted with each other by Schiff base to form an imine bond (C=N), thus crosslinking lysozyme to the membrane and obtaining the dialdehyde pullulan polysaccharide-lysozyme nanofiber membrane (DPul-LZ-M). After crosslinking, the basic performance of the membrane was improved and the hydrophobicity was greatly enhanced. The water contact angles can reach to a maximum angle of 108°. Meanwhile, lysozyme crosslinked on the membranes significantly enhanced the antibacterial activity of the nanofiber membrane. It can achieve the highest antibacterial rate of 95.69 % and 95.46 % against E. coli and S. aureus , respectively. The preservation test indicates that the DPul-LZ-M can extend the shelf life of blueberries. The results showed that DPul-LZ-M has good application prospects in active food packaging.
Haiying Cui,Qun Cheng,Changzhu Li,Myat Noe Khin,Lin Lin
The construction of films has often been devoted to loading active substances to improve biological activity in recent years. However, the positive impacts on packaging properties by establishing a cross-linking reaction between the load materials and the substrate are frequently overlooked. The essence of this work was to cross-linked gelatin-based film with κ-carrageenan and dialdehyde β-cyclodextrin inclusion (IC/DA-β-CD) and the functionalities were also investigated. β-cyclodextrin was oxidized with sodium periodate to introduce aldehyde groups. The hydrophobic cavity was not disrupted and the modified cyclodextrin exhibited solubilization of carvacrol. In addition, the introduction of aldehyde group improved the dispersion effect of cyclodextrin in water, but the solid particles were more likely to gather when exposed to the air. Electrostatic complexation of gelatin and κ-carrageenan significantly ( p < 0.05) enhanced the tensile strength (from 10.85 to 26.54 MPa), surface water contact angle (WCA) from 97.16 to 110.08° and thermal stability of the film. Contrarily, the elongation at break rate decreased significantly and the antibacterial activity was not potent. The crosslinked IC/DA-β-CD further improved the mechanical properties, and excellent barrier capabilities of the film. Consequently, the WCA and thermal stability were further enhanced as well as the antioxidant capacity and antibacterial activity against Listeria monocytogenes (the eradication rate reached 99.989%). Release experiments demonstrated cross-linked film was more suitable for fatty foods with excellent packaging application ability for ready-to-eat (RTE) ham. Based on the promising properties, the cross-linked film has great deal of potential as RTE active packaging.
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