DP2-DP6 Oligomeric Proanthocyanidin Enrichment and Microencapsulation Preserve Antioxidant Function in Maritime Pine Bark Extract

Maritime pine bark extracts contain proanthocyanidins across a broad polymerization range, so total proanthocyanidin content alone does not define the material delivered by a formulation. We prepared a BCLC maritime pine bark microcapsule enriched in DP2-DP6 oligomers using aqueous-ethanol extraction, resin fractionation, sequential membrane separation and composite-wall microencapsulation. Optimized powders contained 70.2-74.8% total proanthocyanidins; DP2-DP6 represented 58.6-62.4%, catechin plus epicatechin 5.1-6.2%, and DP≥10 material 7.3-9.4%. Water activity was 0.31-0.34. The reference formulation retained 93.2% of total proanthocyanidins after 30 days at 40°C/75% RH and 85.1% after 90 days; DP2-DP6 retention at 90 days was 83.6%. Simulated digestion left 78.6% of DP2-DP6 after the intestinal phase. DPPH and ABTS scavenging were 76.8% and 82.1%, and ORAC reached 4,120 μmol TE/g. In H₂O₂-challenged HaCaT keratinocytes, ROS fell to 60.7% of the model value at 100 μg/mL while viability remained above 93%. Human studies of standardized French maritime pine bark extracts have also reported higher plasma antioxidant capacity and lower reactive-oxygen-metabolite measures. The data identify polymerization-degree control and post-processing retention as practical variables for an oligomer-rich antioxidant ingredient.