Feasibility of Hemp Seed Oil Oleogels Structured with Natural Wax as Solid Fat Replacement in Margarine

Cold-pressed hempseed oil (HSO) is known to have many health benefits due to many phytochemicals and high polyunsaturated fatty acids content. In this study, HSO oleogels were prepared with 3, 5, and 7% natural waxes including sunflower wax (SW), rice bran wax (RBW), beeswax, and candelilla wax to evaluate their potential as solid fat replacements in margarines and spreads. Firmness, crystal structures, and melting properties of these oleogels were evaluated. In general, wax-based HSO oleogels except for RBW-HSO oleogels had lower firmness and weaker crystal network than the corresponding soybean oil (SBO) oleogels. In contrast, RBW-HSO oleogels had similar firmness, comparable or stronger crystal network, and higher melting and crystallization enthalpies compared to those of SBO oleogels. After removing polar compounds from HSO, waxes except for RBW provided oleogels with greater firmness, higher melting and crystallization enthalpies, and stronger crystal network. Therefore, it was concluded that polar compounds negatively affected the physical properties of wax-HSO oleogels but not those of RBW-HSO oleogels. Margarine samples were prepared with SW- and RBW-HSO oleogels, and their firmness and melting properties were examined. The firmness of these margarines indicated that wax-HSO oleogels may achieve the firmness of commercial spreads with less than 3% wax while the firmness of stick margarines cannot be achieved even with 7% wax. Although the properties of wax-HSO oleogels should be further improved, they showed potential as solid fat replacements in margarines and spreads.

Crystallization and mechanical properties of carbon nanotube/continuous carbon fiber/metallocene polypropylene composites

In this work, a high fluidity polypropylene prepared with the metallocene catalyst (mPP) was used as matrix, carbon nanotube (CNT) and continuous carbon fiber (CCF) were added to prepare composites, and their mechanical properties, melting and crystallization behavior were investigated. In the mechanical properties, the effects of tension force in the preparation process and compatibilizer maleic anhydride grafted polypropylene (MAPP) on the tensile strength of the composites were researched. The results show that the tensile strength of the composites increases first and then decreases with the increase of tractive force. In addition, the melting and crystallization behaviors and dynamic mechanical behaviors of mPP, CNT/mPP and CNT/CCF/mPP composites were characterized and studied by a differential scanning calorimetry (DSC) and dynamic mechanical analyzer (DMA). The results show that the melting point (Tm ), crystallization temperature (Tc ) and storage modulus (E') of CNT/mPP are all increased by adding 1wt% CNT, especially the Tc is increased by 8.8 ºC. It shows that after CNT was added to mPP as inorganic carbon material, it plays a prominent role in heterogeneous nucleation. After CCF was composited with CNT/mPP, the composites with CCF content of 30 and 42wt% were prepared, and their Tm , Tc , crystallinity (Xc ) and E' were all improved, especially E' was greatly improved, such as the initial E' was increased by 5.64 and 11.74 times. Even at the end of the curve, the E' of the composites with CF is still significantly higher than that of mPP and CNT/mPP. It indicates that adding CCF will greatly improved the deformation resistance and load deformation temperature of mPP.

Melting, Crystallization, and In Vitro Digestion Properties of Fats Containing Stearoyl-Rich Triacylglycerols

Fats containing the stearoyl-rich triacylglycerols (TAGs) of 1,2-distearoyl-3-oleoylglycerol (SSO) and 1,3-dioleoyl-2-stearoylglycerol (OSO) were synthesized via the lipase-catalyzed acidolysis of tristearin (SSS)-rich fat and oleic acids, followed by solvent fractionation. Their physicochemical properties and in vitro digestibilities were compared. The SSS-, SSO-, and OSO-rich fats comprised 81.6%, 52.9%, and 33.1% stearic acid, respectively, whereas oleic acid comprised 2.9%, 37.5%, and 56.2%, respectively. The SSS-, SSO-, and OSO-rich fats contained the TAGs of SaSaSa (100.00%), SaSaMo (86.98%), and MoSaMo (67.12%), respectively, and the major TAGs were SSS, SSO, and OSO, respectively. Melting and crystallization temperatures were higher and fat crystals were larger and densely packed in the descending order of SSS-, SSO and OSO-rich fats. Both in vitro multi-step digestion and pH-stat digestion were more rapid for OSO- than SSO-rich fat. Oleic acid was digested faster than stearic acid during the initial digestion, then the rate decreased, whereas that of stearic acid increased over prolonged digestion. Fats that were richer in stearoyl at the sn-1,3 position of TAG melted and crystallized at higher temperatures, had a densely packed microstructure of large fat crystals and were poorly digested. Stearic acid imparts the essential physical attributes of melting and crystallization in solid fats, and the low digestible stearoyl-rich fat would be a viable substitute for trans fatty acids in food lipid industry.

Physical Properties of Mineral Fibers Depending on the Mineralogical Composition

A developed methodology for determining the physical properties of mineral fibers prepared from different input mixtures under the same spinning wheel conditions is described and discussed. Energy dispersive X-ray fluorescence spectroscopy was combined with simultaneous thermal analysis and thermogravimetry to study the mineralogical composition and typical melting and crystallization temperatures. The mechanical properties measured with nanoindentation were related to the mineralogical properties and the results obtained are in agreement with the literature. The developed methodology shows reliable performance and demonstrates the ability to study the mechanical properties of mineral fibers, their mineralogical composition, and thermal properties. The presented experimental methodology opens up the possibility of researching the mechanical properties of mineral fibers for the purpose of defining production recipes in the field of mineral thermal insulation materials.