Continuous-Flow Pulsed Electric Field Treatment of Potato Fiber: Effects on Microbial Load, Physicochemical Properties, and Functional Characteristics

Potato fiber is a valuable coproduct of potato starch processing, but residual starch and microbial load can limit its quality and application as a food ingredient. This study evaluated continuous-flow pulsed electric field (PEF) treatment for non-thermal microbial reduction and modification of potato fiber properties. Initial batch experiments demonstrated limited microbial inactivation at low electric-field strengths, whereas higher field strengths improved microbial reduction. Continuous-flow treatment at 24 kV/cm was subsequently evaluated at specific energies of 50 and 100 kJ/L, classified as PEF50 and PEF100 respectively. PEF100 resulted in an approximate 1.6-log (96%) reduction in aerobic plate count (APC), greater than 2.5-log (99%) reduction in yeast, and greater than 1 log (97%) reduction in mold. PEF100 also significantly reduced residual starch from 31.7% to 26.8% and increased estimated fiber content from 54.9% to 59.3%. Water-holding capacity was not significantly reduced by PEF treatment, while oil-holding capacity increased modestly following PEF100 treatment. Ash content was unaffected, whereas protein content decreased from 5.8 to 4.7% following PEF treatment. The findings of this study demonstrate that continuous-flow PEF treatment at 100 kJ/L effectively reduced the microbial load and residual starch of potato fiber while maintaining, and in some cases improving, key physicochemical and functional properties.