Characterization of Oleogels Based on Waxes and Their Hydrolyzates

In this paper, the structuring of liquid oils, also known as oleogelation, is systematically investigated for the first time using a quasi-quaternary mixing system approach. Native waxes with different quantities of wax esters (WE), n-alkanes (hydrocarbons (HC)), fatty acids (FA), and fatty alcohols (FaOH) are applied in mixtures with hydrolyzed waxes to systematically change the composition. Hydrolyzed waxes contain high levels of FA and FaOH. The model systems are investigated on microscopic level (brightfield light microscopy (BFM), cryogenic scanning electron microscopy (cryo-SEM)) as well as on their macroscopic properties (rheology, gel hardness) and calorimetric behavior (differential scanning calorimetry (DSC)). It is found that sunflower wax (SFW)-based gels (12% structurant) become less hard on any admixture. Beeswax (BW)-based gels show significant increases in hardness when 25% and 50% (w/w) hydrolyzate are admixed. This could be related to stepwise crystallization. Further analysis reveals that the dissolution/melting behavior of the wax ester mixtures can be surprisingly well described as ideal solubility of a single pseudocomponent. The approach to unravel the individual contributions of the different species present in waxes is successful and marks a first step to better understand the systematic of wax functionality as oleogelators. Practical Application: The substitution of hardstock fats in structured oil phases is of interest for two reasons. The improved nutritional profile oleogels offer are beneficial for public health while the elimination of palm oil based ingredients appears to be a general public desire. Among the technical solutions for non-TAG oil structuring waxes are very promising. This is primarily due to their availability, prior consumption, potentially low cost for functionality. Currently waxes are technically and scientifically wrongly treated as single components. In order to better utilize the potential of waxes and design future sourcing strategies it is necessary to understand the wax functionality at a compositional/molecular level. This contribution marks the first step into this direction by considering classes of molecules with respect to their contribution to functionality. This understanding is considered as a key for future compositional design.     

Crude Wax Extracted from Rice Bran Oil Improves Oleogel Properties and Oxidative Stability

Crude wax extracted from rice bran oil (RBO) is used to improve the oleogel properties and oxidative stability of RBO. The effect of crude rice bran wax (CrBW) on the formation characteristics and oxidative stability of oleogels is discussed. The results show that oleogels can be formed with 7.0 wt% CrBW at 20 °C. As the concentration of CrBW increases from 7.0 to 11.0 wt%, the hardness and solid fat content (SFC) of the oleogels increase significantly, and the oleogels are primarily β' crystals. Moreover, oleogel crystals formed with 5 and 7 wt% CrBW are flocculent; when the amount included is 9%, the oleogel crystals are transformed into long dendrites, and the density rises. After 90 days of storage at 20 °C, the peroxide value of oleogels formed with 9.0 wt% CrBW slowly rises from 3.21 to 6.52 mmol kg⁻¹. Practical Applications: Oleogels prepared here by CrBW and RBO are an innovative structural lipid without trans fats. Useful information on the rich fats and nutrients in CrBW is provided, which reduces the production cost and improves the industrial production capacity.     

不同种类凝胶因子对芝麻油基凝胶油特性的影响

以芝麻油为原料,通过添加虫胶(Shellac,LAC)、单硬脂酸甘油酯(Monoacylglycerol,MAG)、乙基纤维素(Ethyl Cellulose,EC)三种不同种类凝胶因子制备出构型不同的凝胶油,并对凝胶油的持油能力、硬度、热力学性质、结晶形态等特性做了初步研究.结果表明,凝胶因子种类及添加比例对凝胶油临...     

New gelification method for vegetable oils I: cosmetic application

A new gelification process of vegetable oils was developed using a cellulose derivative in order to obtain transparent oleogels (anhydrous gels based on fatty components) of different consistencies. The study of their structure has been carried out by infra-red spectroscopy, differential thermal analysis and X-ray diffractometry. All these physical tests have demonstrated the gel structure of the formulations. Finally, a rheological study was run to elucidate their specific properties and their stability during storage.     

X-ray characterization of three possible edible oleogelators: Experiment and theory

Three oleogelator molecules (Triacontane (TC), Stearic acid (SA), and Behenyl Lignocerate (BL)) were studied individually, in pairs, or all together to make an oleogel using triolein as the oil. WAXS, SAXS and USAXS were used to elucidate the solid structures from angstroms to a few micrometers. A two-dimensional mapping of atomic positions for each molecule was carried out to understand the crystalline multilayer structures formed. We assumed that the molecules were rigidly extended and that they underwent no significant (hindered) rotations so that the free energy is determined by the Lennard-Jones interactions of closely packed multilayers. TC molecules were predicted to form a tilt angle of ${\theta }_t\approx 33°$, yielding a SAXS line at $q\approx 0.194$ Å^─1, in acceptable agreement with the measured $q=0.181{\AA }^{-1}$. For SA crystals ${\theta }_t\approx 33°$ (predicted) yielding a SAXS line at $q=0.150{\AA }^{-1}$ compared to $q=0.159{\AA }^{-1}$ (observed). No mixed crystals were observed for any pair of molecules or when all three were used. USAXS data showed that SA forms large nanocrystals compared to TC and BL. All three combinations of molecular pairs showed basic scatterers smaller or similar to those of individual molecules. The theory presented here, together with the experimental results, showed why no mixed crystals are formed from two or all three molecules. Data from the USAXS region suggested that, when using all three molecules, a more compact fractal structure was obtained, compared with those if one or two of the molecules were used.     

食用植物油脂凝胶化技术研究进展

油脂凝胶化技术在提高液态油脂塑性方面效果突出,并在减少或替代食品中的反式脂肪酸或饱和脂肪酸的应用开发中潜力巨大。综述了植物油凝胶和乳凝胶两大类油脂凝胶的形成机理,凝胶化油脂的制备方法、应用特性等,重点介绍了近年来上述两类凝胶化技术的国内外开发与应用进展,举例分析了该类技术在食品起酥、涂抹填充、巧克力反砂抑制等诸多应用的可行性,并对今后的深入研究方向进行了展望。     

植物甾醇对其凝胶化大豆油结构稳定性和热氧化特性的影响

研究植物甾醇凝胶剂(β-谷甾醇与γ-谷维素质量比2:3)对大豆油凝胶网络结构及氧化特性的影响.结果表明,在植物甾醇凝胶剂添加量为2％～10％(质量分数)时,6％及以上的凝胶化大豆油的G′始终大于G″,说明体系已形成稳定的类固体凝胶结构.偏振光显微镜显示,6％凝胶化大豆油在45℃贮藏10 d时,呈现规则且紧密的聚集态,其...