Enhancing the functional potential and in vitro bioaccessibility of red bell pepper bioactives via pulsed electric field-assisted lactic acid fermentation

Pulsed electric field (PEF) pre-treatment (1.07 kV/cm, 1, 5.5, 10 kJ/kg) was combined with lactic fermentation using Lactiplantibacillus plantarum to modulate red bell pepper matrix structure and subsequent in vitro bioaccessibility of bioactive compounds. Although PEF-assisted fermentation has gained increasing attention, its influence on post-digestion recovery of carotenoids and phenolics remains insufficiently characterized. Fermentation day 5 was identified as the, most favorable processing stage for preserving antioxidant capacity and bioactive compound stability. Moderate PEF (5.5 kJ/kg) enhanced carotenoid accumulation (>220 mg/100 g d.m.) and induced structural reorganization, confirmed by FTIR analysis. Following INFOGEST digestion, samples treated at 5.5 kJ/kg exhibited the highest apparent intestinal bioaccessibility (∼78% polyphenols; ∼39% carotenoids), whereas higher energy input (10 kJ/kg) reduced carotenoid recovery (∼22-24%), demonstrating a non-linear, energy-dependent response. Fermentation after moderate PEF shifted the relative amino acid profile toward a pattern closer to the reference protein, as reflected by higher EAAI values (1.26-1.36 vs 0.84 in the control), despite the decrease in total protein content and total essential amino acid content. These findings reveal intensity-dependent modulation of apparent bioactive release during digestion and provide mechanistic insight into structure-function interactions in fermented vegetable matrices.