High-voltage pulsed electric field pretreatment-assisted freezing to improve the quality of blueberries after freezing and its influencing mechanisms

Traditional freezing techniques damage blueberries by forming large ice crystals, thereby limiting their freshness.This study utilized an artificial neural network (ANN) to optimize the parameters of high-voltage pulsed electric field (PEF)-assisted freezing and compared it with traditional freezing methods.The results showed that pulsed electric field technology significantly reduced the time blueberries required to pass through the maximum ice crystal formation zone during freezing, resulting in smaller, more uniformly distributed ice crystals and more uniform moisture distribution.Compared to traditional freezing, PEF-assisted freezing reduced the relative electrical conductivity of blueberries by 21.36% and malondialdehyde (MDA) content by 34.34%, indicating a protective effect on cellular tissue during freezing. Additionally, differential scanning calorimetry (DSC) experiments showed that PEF pretreatment altered the thermal stability of blueberries, causing them to enter the phase transition stage earlier and reducing the time required to pass through the maximum ice crystal formation zone. This study elucidates the mechanism by which high-voltage pulsed electric field (PEF) pretreatment enhances post-freezing quality of blueberries by accelerating freezing and regulating ice crystal formation. It provides theoretical support for the application of non-thermal processing technologies in the frozen fruit and vegetable industry, opening a new, green, and efficient pathway to address the widespread issue of quality degradation in frozen fruits. This research holds significant practical value for optimizing frozen fruit processing techniques, elevating the standards of the frozen fruit industry, and reducing energy consumption in traditional freezing processes.