The thermal, rheological, and structural characterization of grapeseed oil oleogels structured with binary blends of oleogelator

Abstract

Combination of oleogelators has recently started to receive scientific attention since single oleogelator may not adequately compensate for the diverse roles of solid fat in a complicated food system. In this study, grapeseed oil oleogels were prepared with candelilla wax (CDW) and glyceryl monostearate (GMS) blends at varying mass ratios (100:0, 75:25, 50:50, 25:75, and 0:100 [w/w]), and their physicochemical characteristics were characterized in terms of thermal, rheological, and microstructural properties. The oleogel with CDW and GMS at a blending ratio of 75 and 25 (CDW-75:GMS-25) exhibited the lowest melting point, implying a eutectic behavior. The CDW-75:GMS-25 oleogel also had a harder texture, greater viscoelasticity, and lower oiling-off characteristics that were highly attributed to its small crystals and dense structural network observed from phase-contrast microscopic images. When GMS from different vendors were examined for melting behavior and hardness of oleogels, it was found that the oleogel properties were highly dependent on the detailed composition of GMS. NMR study showed that the ternary system of CDW, glyceryl 1-monostearate, and glyceryl 1,3-distearate was responsible for the eutectic behavior of the CDW-75:GMS-25 oleogel. This study reports the unique and improved melting and physical properties of oleogels with the mixture of CDW and GMS, which can increase the feasibility of the oleogel technology in actual food products. However, caution should be taken in selecting the oleogelators because their detailed composition and properties can vary depending on sources and processing conditions. PRACTICAL APPLICATION: Increasing attention has been paid to the combination of oleogelators since single oleogelator may not adequately compensate for the diverse roles of solid fat in a complicated food system. This study showed new eutectic characteristics at a specific blending ratio of candelilla wax and glyceryl monostearate that could be positively correlated with the increased hardness, viscoelasticity, and oiling-off features. The results may encourage the food industry to utilize this binary oleogelator blend as an alternative to solid fat high in saturated fat by providing new functional properties.