Obtention and characterization of soybean oil organogels structured with sugarcane wax and its hot ethanol soluble fractions Obtención y characterización de organogeles producidos con cera de caña de azúcar y sus fracciones solubles en etanol caliente Recebido: 08/04/2020 | Revisado: 09/04/2020 

Sugarcane wax (SCW) was fractionated using hot ethanol and a simple washout system, the obtained fractions soluble (SSCW) and insoluble (ISCW) were used to produce organogels crystallized at two different temperatures (5 and 25°C) at the concentrations of 1, 2, 3 and 4% (w/w). The laboratory research evaluated the behavior of organgels obtained from sugarcane wax (and its fractions), all organogels were assessed due to its microstructure, thermal behavior, rheological behavior and mechanical resistance. Samples were visually assessed for stability at a controlled temperature oven (at 5, 25 and 35°C), and the thermal behavior for SCW, SSCW and ISCW were different. The enthalpy variation changed from 118.87 to 129.63 and 85.65 J/g for the fractions. Organogels obtained from these materials were somewhat similar during crystallization (TPeak of 42.83, 37.19 and 36.23°C respectively), crystallization and melting enthalpy variation presented hysteresis as observed for other waxy organogels. SSCW organogels were significantly harder than the obtained with SCW and ISCW. Micrographs of the organogels showed a more organized network present on SSCW organogel when compared with SCW that was more organized than ISCW organogels. The difference on the microstructure observed explains the difference on the mechanical behavior of organogels formed with sugarcane wax hot ethanol-soluble and insoluble fractions.

soluble and 43% for the insoluble fractions (ISCW). Both fractions were dried under vacuum and milled.
The thermal properties of SCW and the fractions were measured and are presented in Table 1 (the obtained results were similar to those obtained by Gandra (2006), fatty acids and fatty alcohols compositions are described in Table 2 (Gandra, 2006;Lopes, 2010).

Organogels Preparation
Organogel samples were prepared firstly heating soybean oil up to 80 °C under stirring and SCW, SSCW or ISCW solid wax was slowly added (1, 2, 3 and 4% w/w) and mixed up to its complete dissolution. After complete dissolution, the mixture was kept under agitation without heating for 3 min. The samples were put inside 50 ml glass beakers and stored at 5 or 25 °C for 24 hours to static crystallization and kept at 25 °C temperature up to perform the analysis.
Two temperatures were used for static crystallization aiming to achieve evaluate the effect of different supercooling at the formation of different crystallization polymorphs (Himawan et al., 2006) although it was not possible to evaluate the cooling rates due to processing conditions it is known that with the lower temperature a faster crystallization is expected. became just one phase as shown in Figure 1B for 4% (w/w) organogel samples. after 3 days at 25°C; (A) 1% (w/w), (B) 4% (w/w) and (C) SSCW organogel at 4% (w/w) crystallized at 5°C after 7 days at 35°C.
The SSCW organogels at 4% (w/w) presented oil exudation after 3 days at 35°C at both crystallization conditions (5 and 25°C) as shown in Figure 1C, the oil exudation was not visible for SSCW samples at lower concentrations. All other samples that formed a visually continuous phase did not show oil separation. The results are similar to those observed by Rocha et. al. (2013) for organogel samples produced using SCW and also candelila wax.
Based on polarity it is possible to explain why the ISCW showed lower stability specially compared to the SSCW, with polarity similar to the studied soybean oil. If we observe the polarity table presented by Hwang et. al. (2015), it is the expected behavior with similar polarity the organogels are expected to be more stable and organized, and at the present study the same behavior was observed.

Thermal Analysis
The thermal properties of SCW, SSCW and ISCW were measured, the Figure 2A shows the crystallization of the waxes and it is possible to observe that the waxes presented changes on the crystallization behavior especially the peak temperature, 67.88°C for SCW changed to 54.98 and 66.89°C for SSCW and ISCW respectively. The enthalpy variation changed from 118.87J/g for SCW to 129.63J/g for SSCW and decreased to 85.65J/g for ISCW.
Research, Society and Development, v. 9, n. 6, e46963471, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i6.3471 The melting behavior was presented in Figure 2B and allows to observe that organogels from SCW and ISCW presented very similar peaks (although with different intensities) while SSCW was different. The measured peak temperature for melting was 61.91°C for SCW, 60.77 and 65.41°C for SSCW and ISCW respectively. The enthalpy variation changed from 121.70J/g for SCW to 132.27J/g for SSCW and decreased to 87.21J/g Research, Society and Development, v. 9, n. 6, e46963471, 2020 (CC BY 4. The crystallization thermogram for ISCW also indicates that this fraction is, a concentrate of some of the wax components, as expected, presenting a narrower and pronounced peak which for thermal analysis represents pure components (Campos, 2005), allowing to see that this fraction presents a higher uniformity.
At SSCW thermogram a wider peak is presented, but without the presence of the higher peak that is present on the SCW and were pronounced for ISCW, such difference should be due to chemical composition, according to Gandra (2006), the ISCW presented an increase from 22.5 to 39.6% of the amount of palmitic acid when compared with SCW and also presented a decrease of the amount of fatty alcohols from 21 to 18% (w/w), also SSCW presented 59.5% of octacosanol compared with 51.1% of ISCW, but also the SSCW presented an increase of the fatty alcohols content from 21 to 25% compared with SCW (Gandra, 2006;Vieira, 2003). The 4% (w/w) organogels samples obtained with each of the waxes were also evaluated and the crystallization and melting thermograms presented in Figure 2A and 2B respectively. The calculated thermal parameters are presented in Table 3, they allow to observe that compared with the SCW organogel, both fractions presented a change on enthalpy variation (ΔH), for melting, this difference should be related to the separation of  Figure 3A shows the organogel developed with 4% (w/w) of SCW at 5°C while Figure   3B shows the same material crystallized at 25°C. At both images it is possible to observe the presence of needle-like crystals that should represent a bi-dimensional view of the network that keeps the liquid phase immobilized, we can notice that the crystals on Figure 3A are slightly smaller than the observed on Figure 3B, 3.8 ± 0.7 and 4.2 ± 0.9 μm respectively, but it is possible to observe a higher organization of them at Figure 3B.
The organogels obtained with SSCW at 4% (w/w), at 5°C are shown in Figure 5C and Development, v. 9, n. 6, e46963471, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i6.3471 14 25°C on Figure 3D. On Figure 3C it is possible to observe a lot of crystals so small that measured around 2.0 ± 0.3 µm and at Figure 3D it is possible to observe a large amount of crystals with the average size of 3.5 ± 0.7 μm.
For ISCW organogels the micrograph of the organogels at 4% (w/w) as shown in Figure 3E and 3F, shows a large difference among the materials obtained at 5 and 25°C. On Figure 3E the organogel was obtained at 5°C and it is possible to observe an organized structure with crystals of 5.1 ± 1.1 μm, while on Figure 3F the observed crystals were larger (7 ± 1.8 μm) and also a smaller organization on the network was observed, being possible to observe crystals that were not part of the network.
The observation using polarized light microscopy corroborated the results obtained for mechanical properties, a more organized network as seen in Figure 3B and Figure

Scanning Electronic Microscopy (SEM)
At Figure 4B, 4D and 4F (where the 25°C organogels are presented), it is possible to observe that the SCW and its fraction organogels are indeed a three-dimensional network at a rupture point (the material suffered a volume reduction due to the removal of the liquid oil). Once the measure of the cells was not possible once the material was modified, the structure of the material can be observed as a really organized structure of a foam-like network, as observed in the literature (Ema et al., 2006), such authors used SEM of polymeric foams and it was possible to observe the resemblance among their material and the studied organogelator has been evaluated and confirmed, for the next steps a better understanding of how organogels behave under shear during food processing should allow the inclusion of organogels structured food at our shelves.