Influence of water content and emulsifiers on the stability and texture of oleogel-emulsions
Rycal J. S. Blount, Jannatul Ferdaus, Roberta Claro da Silva
Abstract
• Phospholipon 90 G emulsions with 1.5 % or 2 % emulsifier and 10 % water exhibited the highest oil binding capacity. • Soy lecithin emulsions provided greater structural strength and stability, while P90 G emulsions excelled in spreadability for lighter textures. • Polarized light microscopy confirmed that phospholipon 90 G emulsions with lower water content and high emulsifier concentrations were most stable. This study evaluated the impact of water and emulsifier additions on the oil binding capacity (OBC), texture properties, and stability of oleogel-emulsions. Oleogels were prepared using beeswax and glycerol monostearate (7:3) as the oleogelators (10 %) with soybean oil. The physical properties of emulsions were examined based on the different ratios of emulsifiers e.g., Phospholipon 90 G (P90 G), Soy Lecithin (SL), and Tween (T80) and water content. OBC test showed that 1.5 % P90 G and 10 % water emulsion had the highest value (86.85±1.0 %) at 7 days. The emulsion's OBC followed the trend: P90 G > SL > T80. However, the emulsion formulated with 0.5 % P90 G and 15 % water had the lowest firmness (0.38±0.05 N), toughness (0.61±0.12 N.mm), and adhesiveness (0.06±0.01 N. sec ) and the highest spreadability (0.19±0.04 N. sec ). Conversely, emulsion prepared with 0.5 % T80 and 10 % water showed the highest firmness, toughness, and adhesiveness and the lowest spreadability (2.18±0.32 N. sec ). In addition, SL emulsion also showed higher values for texture properties while lower value for spreadability in a consistent way. Further PLM images showed that high concentration (2 %) of P90 G and SL with 5 % water were stable at 40 °C, while 2 % T80 were stable at any percentages of water. These findings suggest that P90 G emulsion is preferrable if the application focuses on spreadability and light texture, which do not need to hold a shape over time. Conversely, SL emulsions are more tough, which is essential in products that are exposed to external forces. These findings highlight the potential of these glycerol monostearate-based oleogel-emulsions as stable systems for various applications.