Guangxin Feng,Gaoshang Wang,Qing Li,Chuanwu Han,Dong Wei,Jian Guo,Zhili Wan,Jinmei Wang,Xiaoquan Yang
3D printing has been applied to create nutritious foods with tailored textures for the elderly. However, the edible materials that possess the elastoplastic properties and shear-thinning behavior required for direct-write 3D printing are limited. In this study, we developed a simple approach to fabricate Spirulina emulsion gels as edible 3D printable material by exploiting depletion attraction between emulsion droplets. By controlling the volume ratio of continuous and oil phases, mixing highly viscous Spirulina slurry and vegetable oil could form self-standing oil-in-water emulsion gels with elastoplastic rheological properties. Also, adding food polysaccharides into the continuous phase could act as depletants to drive the formation of emulsion gels. Auto-fluorescence spectroscopy and microscopy were employed to characterize the interfacial protein compositions of the emulsion, showing that phycobilisome (PBS) particles might play a dominant role in the formation of Spirulina emulsions. The depletion attraction could drive the adsorption of PBS particles onto the droplet interface, and the particle-armored droplets in the dispersed phase connected into a percolating droplet cluster, resulting in arrested dynamics and gelation . Overall, this novel approach can be applied by exploiting depletion attraction and opens up possibilities for using high-solids viscous food slurries to produce personalized 3D-printed foods.
A novel mesoporous fluorescent molecularly imprinted sensor for selective detection of bisphenol A (BPA) in food materials was fabricated via a semi-covalent imprinting method. The imprinting precursor that served as an alternative template molecule for BPA was prepared via thermally reversible isocyanate bonding, which effectively improved the imprinting efficiency for the molecularly imprinted sensor. Carbon dots (CDs) were embedded in mesoporous silica as signal recognition elements that exhibited quenching upon BPA binding. Subsequently, through the sol–gel process, the molecularly imprinted layer was coated on the CDs silica layer and provided specific recognition sites for BPA. The composite of CDs embedded in the mesoporous molecularly imprinted polymer (CDs@MIP) was characterized with scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller measurements and thermogravimetric analysis. The mechanism of carbon dots quenching and the high selectivity of CDs@MIP towards BPA were explored. The linear response range of the sensor was from 0.025 mg L−1 to 2 mg L−1 with a limit of detection of 0.016 mg L−1. The method was successfully applied for the determination of food samples and recoveries ranged from 92.5% to 101.1%. The BPA contents in actual samples were determined using high performance liquid chromatography and the proposed sensor, showing no significant difference between the two methods.
An emulsion with a consistent average droplet size, stabilized by either Tween20 or soy protein isolate (SPI), was added into a SPI/arabinoxylan (AX) double-network gel matrix to create emulsion-filled gels (EFGs). The emulsifier type and SPI/AX matrix composition affected the freeze-thaw stability of EFGs via changing interactions of interfacial and matrix interactions. The results of Fourier transform infrared spectroscopy, Fluorescence spectroscopy, Molecular docking and Dynamics simulations confirmed that more hydrogen bonds formed between the SPI molecules than between Tween20 and SPI. Thermogravimetric analysis also revealed that interfacial SPI was bonded with gel matrix and integrated into the network. During freeze-thaw cycles, stronger molecular interactions and a more interconnected network delayed β-sheet formation and protein reorganization. SPI/AX ratio affected the freeze-thaw stability via changing molecular interaction among macromolecule of gel matrix. A higher proportion of AX exhibited the strengthened interactions with SPI matrix. This delayed the protein denaturation and phase separation of the double networks. EFG with higher AX content tended to adopt a more ordered conformation, as evidenced by an increase in the α-helix content during freeze-thaw cycles. These findings indicate that matrix and interfacial interactions enhance freeze-thaw stability, significantly expanding the application of emulsion-filled double-network gels in frozen foods.
危险品化学品经营许可证（带存储）