Structural and Physical Characteristics of Mixed-Component Oleogels: Natural Wax and Monoglyceride Interactions in Different Edible Oils

Abstract

Waxes and monoglycerides (MGs) added in edible oils form oleogels that can be used as an alternative structured fat, providing healthier substitutes to saturated and trans fats in foods. This study aimed to investigate the properties of oleogels formed by the interaction between monoglycerides and different waxes in various edible oils. For this purpose, waxes, namely rice bran (RBW), candelilla (CDW), sunflower (SW), and beeswax (BW), together with MGs in a total concentration level of 15% (w/w) were dissolved in several edible oils (olive, sunflower, sesame, and soybean). The structure and physical properties of oleogels were investigated using texture analysis, polarized light microscopy, melting point measurements, and Fourier-transform infrared spectroscopy (FTIR). The hardest structure was produced by SW/MG (5.18 N), followed by CDW (2.87 N), RBW (2.34 N), BW (2.24 N) and plain MG (1.92 N). Furthermore, RBW and SW led to a higher melting point (69.2 and 67.3 °C) than the plain MG oleogels (64.5 °C). Different crystallization structures, i.e., needle-like crystals and spherulites, were observed depending on the type of wax, its concentration, and the oil used. These results can be used to control the properties of oleogels by adjusting the gelator composition for a variety of potential food applications.

Microstructure, Physical Properties, and Oxidative Stability of Olive Oil Oleogels Composed of Sunflower Wax and Monoglycerides

“…Nevertheless, a concentration exceeding 10% w / w is deemed appropriate for establishing a crystalline network that traps the oil [ 19 ]. Therefore, in order to both decrease the MGs concentration and enhance the stability and physicochemical properties of oleogels, MGs can be combined with other structurants, such as phytosterols [ 8 , 20 , 21 ], waxes [ 22 , 23 , 24 , 25 ], etc. Waxes are another type of structurants that can be effective at forming crystalline structures at low concentrations [ 26 ].…”

“…Waxes are another type of structurants that can be effective at forming crystalline structures at low concentrations [ 26 ]. Several natural waxes have been studied in the literature, including carnauba wax [ 27 , 28 ], rice bran wax [ 26 , 29 ], candelilla wax [ 30 , 31 ], sunflower wax [ 25 , 32 ], and beeswax [ 33 , 34 ]. Typically, waxes consist of a variety of chemical constituents, such as long-chain fatty alcohols, long-chain fatty acids, straight-chain alkanes, and wax esters [ 35 ].…”

“…The individual components in waxes differ both in concentration and in ingredients according to their type. Waxes that are rich in wax esters and fatty alcohols create oleogels with a higher hardness [ 25 , 36 ]. Even though wax-based oleogels result in desirable physical properties and oxidative stability compared to MG-based oleogels [ 37 ], they lead to an unpleasant waxy mouthfeel, limiting their use [ 38 ].…”

Characterization of Beeswax and Rice Bran Wax Oleogels Based on Different Types of Vegetable Oils and Their Impact on Wheat Flour Dough Technological Behavior during Bun Making

“…Different factors such as natural wax type, oil type, and wax concentration level may affect the characteristics of oleogels. For beeswax, the critical concentration of oleogel formation for most vegetable oils is around 6.0% w / w [ 9 ], whereas for rice bran it is 5.0% w / w [ 10 , 11 ]. An increase in wax levels decreases the gelation time.…”

“…At the same time, the fatty acid composition of oils affects oleogel properties. For example, an oleogelator’s gelling ability may increase if the vegetable oil used for oleogel production presents a higher amount of saturated fatty acids in its composition [ 9 , 12 ]. According to our previous study, oleogels formulated with olive oil, grape seed oil, hemp seed oil, walnut oil, and sunflower oil using white beeswax (3%, 7%, and 11%) show high potential for saturated fat reduction in fat-based food products [ 3 ].…”