Sea fennel as a novel functional ingredient in extruded snacks: Physical, techno-functional, microstructural, antioxidant, and sensory properties

Abstract

The potential of sea fennel (Crithmum maritimum L.), a bioactive-rich halophytic plant, as a functional ingredient in corn-based extruded snacks was investigated. A co-rotating twin-screw extruder was employed to produce snacks using varying sea fennel (SF) content (0–8%), feed moisture (FM: 16 and 18%), and barrel temperature (BT: 140 and 155°C). The extrudates were evaluated for their physicochemical properties, textural attributes, structural characteristics, bioactive composition, and sensory acceptability.

Increasing SF content significantly increased the total phenolic content and antioxidant activity. The total phenolic content increased up to 54.17 mg GAE/g, while antioxidant activity reached 1.47 mg TEAC/g. Physical constraints affected by higher fiber loads imposed; the expansion ratio ranged from 2.84 to 4.55, apparent density from 0.0782 to 0.1389 g/cm³ , and hardness from 145.98 to > 500 N, indicating that SF incorporation and processing conditions markedly affected the physical and textural properties of the snacks. Higher BT (155°C) and lower FM (16%) partially mitigated these textural compromises by promoting matrix expansion and crisp texture development. X-ray diffraction data demonstrated a reduction in relative crystallinity with SF addition, with RC values ranging from 20.6% to 29.9%. Micro-CT analysis indicated highly porous cellular structures, with porosity values ranging from approximately 81.6–87.5%, and suggested formulation-dependent differences in pore morphology. Sensory evaluation identified the formulation with 6% sea fennel processed at 155°C and 16% moisture as the most desirable condition. These findings suggest that sea fennel can be successfully valorized in extruded snacks, providing a novel pathway for developing fiber-rich, antioxidant-fortified functional foods.