Abstract:Probiotic enrichment in fresh-cut fruits was achieved in the impregnation system when induced alternating electric field was used in conjunction with rotating perpendicular magnetic field. The method was intended to promote the efficiency of Lactobacillus rhamnosus diffusion into the tissues of apples and strawberries based on the experimental transformer structure. The amount of probiotic in the sample tissues was investigated under the influence of voltage levels (1 V/cm, 2 V/cm, 3 V/cm), voltage frequencies (50 Hz, 200 Hz, 400 Hz), magnetic field intensities (260 Gs, 900 Gs, 1 300 Gs), rotating magnetic frequencies (0.1 Hz, 1 Hz, 10 Hz), temperature (20℃, 40℃, 60℃, 80℃) and the pH values (3.2, 3.5, 4.6, 5.5, 6.9, 8.1, 10.7) of the impregnation solutions. It was demonstrated that high voltage levels and magnetic field intensities were conducive to the diffusion of probiotics into the sample tissues. The highest amount of probiotic in the sample tissues was achieved at system voltage of 3 V/cm and magnetic field intensity of 1 300 Gs. The maximum amounts of probiotic in fresh-cut apples and strawberries were increased to 9.23×10 8 CFU/g and 1.22×10 8 CFU/g, respectively. Impregnation solutions with low pH values were conducive for the accumulation of probiotics in the samples. The highest amounts of Lactobacillus rhamnosus were 4.32×10 8 CFU/g and 5.4×10 7 CFU/g in the fresh-cut apples and strawberries, respectively, during processing at pH values of 6.9 and 8.1 which showed lower living bacterium content in fresh-cut fruits compared with the samples in the acidic impregnation solution. The optimal electric field frequency and magnetic field frequency for impregnation treatment of fresh-cut apples through this magnetic-electric method were at 200 Hz and 1 Hz, respectively. The proposed impregnation method can provide a reference for probiotic enrichment of fresh-cut fruits.