Pulsed Magnetic-Field-Assisted Extraction of Bilberry Anthocyanins: Mass-Transfer Kinetics and Growth Response of Lacticaseibacillus rhamnosus GG

Bilberry (Vaccinium myrtillus L.) contains high levels of anthocyanins and other phenolic compounds. This study evaluated pulsed magnetic-field-assisted extraction (PMF) as a means of intensifying anthocyanin mass transfer and examined the antioxidant properties of the resulting extract and its effect on Lacticaseibacillus rhamnosus GG (LGG) growth. PMF and untreated extraction were compared over 240 min. Extraction kinetics were described with first-order and Peleg models, and apparent effective diffusivity was estimated from a spherical Fickian diffusion approximation. The mean final anthocyanin amount was 9.57% higher under PMF treatment conditions. Extraction was faster under PMF conditions: the apparent first-order rate constant increased from 0.00761 to 0.01021 min−1, and the half-extraction time decreased from 91.23 to 67.93 min. The Peleg initial extraction rate approximately doubled, and apparent effective diffusivity increased from 1.29 × 10−13 to 1.72 × 10−13 m2 s−1. These kinetic estimates indicate faster anthocyanin release under PMF conditions during the observed extraction period. The extract showed high phenolic content and antioxidant activity. Terminal LGG viable counts were lower than in the control at 0.1 and 0.5 mL/L and higher at 9.0 mL/L. These findings support PMF as a promising process-intensification approach for bilberry anthocyanin extraction and show a dose-dependent LGG response to the extract under the tested conditions.