Enhancing Chocolate Spread with Olive Oil Emulgel as a Functional Product
Amira E. Abd El-Gwad
Agricultural Research Center, Food Technology Research Institute, Giza 12611, Egypt.
Eman,Sh. A. Ghoname
Agricultural Research Center, Food Technology Research Institute, Giza 12611, Egypt.
Mohamed Abdelbaset Salama *
Agricultural Research Center, Food Technology Research Institute, Giza 12611, Egypt.
*Author to whom correspondence should be addressed.
Abstract
This study developed olive oil–based emulgels structured with beeswax (6–12%) and evaluated their physicochemical, oxidative, and functional performance, as well as their application as butter replacers in spreadable chocolate. Increasing beeswax from 6% to 12% accelerated gelation (6.41 ± 0.22 → 3.63 ± 0.12 min) and enhanced structure, evidenced by higher firmness (4.12 ± 0.08 → 9.25 ± 0.18 N) and oil binding capacity (OBC; 92.34 ± 0.61 → 97.35 ± 0.42%). Oxidative stability improved, with peroxide value decreasing (3.85 ± 0.13 → 2.95 ± 0.07 meq O₂/kg) and Rancimat induction time increasing (5.82 ± 0.15 → 8.32 ± 0.14 h). Acid value rose slightly (1.15 ± 0.05 → 1.25 ± 0.05 mg KOH/g). Color shifted modestly (L*: 78.45 ± 0.31 → 73.82 ± 0.31; a*: −2.12 ± 0.05 → −1.72 ± 0.03; b*: 17.31 ± 0.20 → 15.85 ± 0.15). Fatty acid composition remained largely conserved: oleic 73.12 ± 0.34% in olive oil vs. 71.11–71.25% in emulgels; palmitic 11.21 ± 0.13% vs. 12.22–12.35%; stearic 2.73 ± 0.05% vs. 2.85–2.94%; linoleic 10.53 ± 0.15% vs. 9.93–10.14%; linolenic ~0.59–0.61%. Total phenolic content (≈145 mg GAE/kg) and DPPH scavenging (≈56%) were unchanged by beeswax level. Replacing butter with emulgel (0–100%) in spreadable chocolate increased lightness (L* 28.45 ± 0.52 → 30.76 ± 0.61) and yellowness (b* 12.76 ± 0.34 → 14.28 ± 0.29), reduced peroxide value (1.35 ± 0.08 → 0.85 ± 0.06 meq O₂/kg), and elevated antioxidant metrics (TPC 0.95 ± 0.06 → 2.18 ± 0.09 mg GAE/g; DPPH 22.34 ± 1.11% → 54.76 ± 1.37%). Texture and rheology shifted toward softer, more spreadable products: firmness 5.46 ± 0.23 → 2.18 ± 0.17 N; spreadability 18.34 ± 0.65 → 28.45 ± 0.74 mm; viscosity at 10 s⁻¹ 45.32 ± 1.27 → 26.48 ± 1.11 Pa·s; n increased from 0.42 ± 0.02 to 0.49 ± 0.03. DSC showed lower melting transitions with higher emulgel (To 28.45 ± 0.36 → 21.62 ± 0.28 °C; Tp 33.62 ± 0.29 → 27.36 ± 0.33 °C; ΔH 78.24 ± 2.18 → 35.72 ± 1.64 J/g). Overall, beeswax-structured olive oil emulgels deliver enhanced oxidative stability and favorable techno-functional attributes, enabling partial-to-total butter replacement in chocolate spreads while improving antioxidant status and spreadability.
Keywords: Olive oil-based emulgel, beeswax structuring, butter substitution, oxidative stability, rheological behavior, thermal properties, antioxidant retention