Emulsion-Templated Oleogels from Citrus Fiber and Pumpkin Seed Oil By-Product as Palm Oil Substitutes in Chocolate Sauce

Oleogel-based fat systems were developed using citrus fiber (CF) and cold-pressed pumpkin seed oil by-product (PSB) through an emulsion-template approach and evaluated as palm oil substitutes in a model chocolate sauce system. Oleogels were prepared by varying CF (4–5%) and PSB (0–2%) concentrations and characterized in terms of rheological, textural, and sensory properties and oxidative stability. The emulsions exhibited predominant elastic behavior (G′ > G″), with storage modulus (K′) values increasing from 694.12 to 2242.54 Pasn as CF and PSB concentrations increased. Chocolate sauces formulated with CF–PSB oleogels showed pseudoplastic flow behavior and solid-like viscoelastic characteristics, with K′ values ranging from 89.32 to 356.56 Pasn, compared to 34.84 and 16.95 Pasn for the palm oil (C1) and sunflower oil (C2) controls, respectively. Temperature sweep and thermal loop tests demonstrated improved thermal resistance and emulsion stability in oleogel-containing chocolate sauces. Oleogel-based chocolate sauces also showed superior emulsion stability under thermal cycling and greater oxidative stability compared to the C2 sample. Texture profile analysis revealed increased hardness and spreadability with higher CF and PSB contents, consistent with rheological findings. Oleogel-based chocolate sauces also demonstrated enhanced oxidative stability, with induction period values reaching 18:55 h compared to 5:13 h for the sunflower oil control and approaching the palm oil control (20:13 h). Texture profile analysis revealed increased hardness and spreadability with higher CF and PSB contents. Sensory evaluation indicated that sauces containing 5% CF and 1–2% PSB received the highest scores for flavor, consistency, and overall acceptability.