Ulva lactuca Extract in Confectionery Systems: A Sustainable Approach to Natural Pigmentation, Antioxidant...

The replacement of synthetic additives with sustainable, marine-derived bioactives represents a critical step toward meeting the growing consumer demand for clean-label and functional confectionery products. This study aimed to investigate the functional potential of Ulva lactuca extract as a natural colorant and antioxidant in sugar-based confectionery (fondant) and aerated desserts (meringue). The green macroalga, rich in phenolic compounds and pigments, was incorporated at different concentrations to assess its impact on chromatic properties, antioxidant capacity, physicochemical stability, texture, and sensory acceptability. Comprehensive analyses included CIE L*a*b* colorimetry, dry matter content, water activity, DPPH/ABTS radical scavenging assays, total phenolic quantification, FT-IR, SEM, texture profile analysis, and hedonic sensory evaluation. Ulva extract significantly enhanced total phenolic content and antioxidant activity for both model matrices in a dose-dependent manner. The meringue matrix showed a ≈7-fold increase in phenolic levels, reaching up to 150.95 mg GAE/100 g dry matter at 0.63% extract, while maximum antioxidant capacities achieved were 33.42 μM TEAC/g dry matter and 53.28 μM TEAC/g dry matter for ABTS and DPPH assays, respectively. Chromatic shifts toward green-yellow hues aligned with chlorophyll and carotenoid profiles, while textural analysis revealed significant alterations. Sensory evaluation identified matrix-specific optimal thresholds, with fondants demonstrating higher resilience (up to 0.31%) compared to meringues (0.08%-0.16%) in balancing enrichment with acceptability. Overall, meringues exhibited superior functional performance, achieving a substantially higher phenolic fortification and antioxidant surge compared to the fondant matrix. These findings position Ulva lactuca extract as a sustainable, multifunctional ingredient for sugar-based confections, offering antioxidant fortification and natural pigmentation. The study underscores the importance of concentration thresholds to harmonize functional benefits with sensory quality, advancing the development of clean-label, marine-derived functional foods.