The main objective of this study was to investigate the effect of combining a high-melting wax (sunflower wax or rice bran wax) with a low-melting wax (berrywax or BEW) on the crystallization and gelation behavior of the corresponding wax-based oleogels in rice bran oil (RBO). Sunflower wax (SW) and rice bran wax (RBW) have a similar chemical composition but a very different crystallization behavior. Therefore, SWand RBW were also combined in a wax-based oleogel to examine the occurrence of co-crystallization and/or crystal coexistence. The thermal and gelation behavior of the binary blends in rice bran oil (5% w/w total concentration of wax) were investigated with differential scanning calorimetry (DSC) and rheological measurements, showing sequential crystallization and gelation for the SW/RBW : BEW wax-based oleogels and simultaneous crystallization and gelation for the SW : RBW wax-based oleogels. Oscillatory shear and hardness measurements revealed the reinforcement of the high-melting wax crystal network with the addition of the low-melting berry wax. X-ray diffraction (XRD) measurements in both the long-spacing and the short-spacing region showed the occurrence of crystal co-existence, rather than co-crystallization, which was confirmed with polarized light microscopy (PLM). Two different crystal morphologies could be discerned for all three combinations (RBW : SW, SW : BEW and RBW : BEW). We hypothesized that the improved rheological properties could be attributed to sintering, a process in which the low-melting BEW crystals form solid bonds between the crystals of the high-melting waxes. As such, a cohesive network is formed, resulting in an increased hardness of the bi-wax-based oleogels. This research provides the opportunity to minimize the amount of wax necessary in creating semi-solid materials with a wide variety in rheological and textural properties
Oleogelation has recently emerged as a subject of growing interest among industrial and academic researchers. One of the main concerns when working with oleogels is finding the ideal food‐grade oleogelators with right functionalities and universal applications. Identifying synergistic combinations of well‐known food ingredients could possibly help us overcome this issue. In this work we have identified for the first time, that the combination of monoglycerides (MGs) and phytosterols (PS) at certain ratios leads to the formation of mixed component gels that are better than either of the mono component gels. Oleogels were investigated in terms of their rheological properties, crystallization aspects, and microstructural attributes. Three different types of MGs were combined with commercial‐grade PS in different ratios to structure sunflower oil into viscoelastic gels. Polarized light microscopy images of all the samples revealed the formation of three‐dimensional network of entangled crystals, leading to the physical trapping of liquid oil within the interspace structures. Amplitude sweeps showed that the gels formed from these oleogelators had predominantly solid‐like structure (G′ > G″). The mixtures of MGs:PS at 8:2 ratio showed a promising combination as the G′LVR obtained was much higher than gels prepared by using individual components. Based on the crystallization and microstructure studies, it can be speculated that the presence of PS assisted in disintegrating the crystalline clusters and flocs of MGs crystals resulting in gels with better rheological properties compared to mono component oleogels. Practical applications: Oleogelation has emerged as a subject of growing interest in the last couple of years fuelled both by real industrial needs and curiosity for fundamental research among academic researchers. However, one of the main bottlenecks in commercial application of this approach is the lack of ideal food‐grade oleogelators. In this work we have identified for the first time, the synergistic interactions among monoglycerides and phytosterols which leads to the formation of mixed component gels. The resultant gel from that combination can later be used as either an alternative to saturated fat or delivery of functional ingredients. Saturated fat replacement in margarine or butter formulation could be the main application of this oleogel. This is due to the fact that both of the oleogelators used to structure sunflower oil in this research have been used widely in food application. In addition, oleogelators used to structure sunflower oil are available widely in the market. Oleogelation has recently emerged as a subject of growing interest among industrial and academic researchers. One of the main concerns when working with oleogels is finding the ideal food‐grade oleogelators with right functionalities and universal applications. Identifying synergistic combinations of well‐known food ingredients could possibly help us overcome this issue. In this work we have identified for the first time, that the...
Foams with a continuous oil phase may be stabilized using crystalline particles. Those systems are compelling because of their potential in edible oil structuring, modifying sensorial properties and creating healthier food products. This study aimed to relate oleogel (unwhipped state) properties to oil foam (whipped state) properties using a monoglyceride-sunflower oil model system. The properties of crystal-oil mixtures were influenced by time and temperature during preparation and storage. Therefore, oleogels were prepared using different tempering protocols and their resulting microstructure was investigated with rheology, differential scanning calorimetry and X-ray diffraction. The corresponding oil foams were characterized in terms of foamability and foam stability. The properties of both systems were studied immediately after preparation as well as after 4 weeks of storage. We demonstrated that there is a large influence of the time-temperature history on the foam properties. Partially crystallized mixtures were shown to form weaker structures which capture more air because of their lower viscosity and as crystallization would preferentially take place at the interface. They were characterized by larger bubbles and were less stable and firm. It is proposed that their rheological properties are mainly dominated by interfacial contributions. Fully crystallized and stored monoglyceride-oil mixtures were seen to form stronger gel networks which included less air, contained smaller air bubbles and were stable during storage. It is hypothesized that these samples also included an important bulk gelation contribution.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.