Design and Optimization of a Microchip Operating at Low-Voltage Pulsed Electric Field for Juice Sterilization

Microchip has been widely used in the biochemical field, but it is rarely applied in the food area. In this paper, an optimal microelectrode model was obtained via the improved evolutionary structural optimization (ESO) method, the effect of topological parameters on the sterilization efficiency was clarified, and the optimized microchip was applied to the sterilization of blueberry juice to verify its feasibility. The analysis of finite element method (FEM) results showed that planar comb teeth (PCT) form, quadrilateral electrode structure with 100-mu m electrode spacing, was the ideal model for the microchip. On the basis of the optimal electrode model, a continuous low-voltage pulsed electric field (LPEF) experimental platform was built. Under 400 V and 0.2-ms conditions, LPEF processing better preserved vitamin C, anthocyanin, total phenolics content, and color parameters while reducing microbial counts in blueberry juice significantly. During 30 days of storage at 4 degrees C, LPEF-treated juices had more vitamin C, anthocyanin content, and brighter color under the premise of ensuring microbiological safety, compared with high temperature short time (HTST) and pulsed electric field (PEF)-treated juices. This study provides theoretical and technological support for the widespread use of LPEF technology in the application of a non-thermal processing technique for food.