Pulsed electric field pre-treatment of sweet potato: cultivar-dependent effects on phytochemical stability and bioaccessibility.

Pulsed electric field (PEF) pre-treatment is proposed to improve drying and phytochemical bioaccessibility, but its effect in starch-rich matrices is unclear. Three sweet potato cultivars differing in flesh pigmentation were processed into flour under the same nominal PEF treatment (3.1 kV cm-1; mean 10.4 kJ kg-1) in aqueous medium. PEF did not shorten drying at 75 °C and raised moisture and water activity. It reduced phenolics reaching the intestinal phase in two cultivars, and the purple-fleshed cultivar lost ≈83% of anthocyanins before digestion; without an immersion-only control, this loss most plausibly reflects combined aqueous immersion and electroporation, possibly with oxidative or pH-mediated contributions. Fractionation recovered 87-95% of carotenoids and anthocyanins in an insoluble fibre-, starch-associated fraction. Cultivar dominated colour, composition, and most digestion outcomes (η2 ≥ 0.52), except anthocyanins, for which PEF and its interaction with cultivar exceeded cultivar; PEF dominated moisture and water activity (η2 = 0.70-0.74).