Physical properties of oleogels fabricated by the combination of diacylglycerols and monoacylglycerols

Oleogelation is an efficient way to structure oil and reduce saturated fatty acids of lipid products. Multi-component gels are of particularly interest attributed to the ability to tune gel properties by alteration of the component proportions. In this study, monoacylglycerol (MAG) and diacylglycerol (DAG) are used as gelator mixture and the influence of the ratio of these two crystalline particles on the characteristics of oleogels was investigated. The crystallization and melting behavior, solid fat content (SFC), crystal morphology, polymorphism and mechanical properties of the oleogels were characterized. The oleogels with higher gelator level displayed higher oil binding ability and shorter crystal formation time. The oleogels with higher MAG ratio exhibited more blade-like crystals, and the mixed oleogels with MAG: DAG of 3:7 and 5:5 showed altered crystal morphology with finer crystal size and reduced crystallization enthalpies possibly due to the increased nucleation seeds promoted by MAG. The oleogels with high MAG level showed lower equilibrium SFC during isothermal crystallization but faster crystallization rate, higher hardness and elasticity. Therefore, by changing the ratio of DAG with MAG, the crystallization profile and rheological properties of oleogels can be tailored and used as traditional solid fat substitutes in lipid-based products.

Inhibitory effect of thyme oil as an antioxidant for waste cooking oil biodiesel crystallization

The effects of thyme oil extract as an antioxidant on crystallization properties of waste cooking oil biodiesel were investigated. The inhibitory effect was determined for ASTM D7545 standard method for biodiesel added with 1000, 2000, and 3000 ppm of additives by using oxifast device and compared with the chemical antioxidant butylated hydroxytoluene (BHT). Inhibition time data were determined by converting the oxidation stability analysis results. The crystallization temperatures (Tcr) of the samples were determined by using a Differential Scanning Calorimetry (DSC) technique. Tcr values of samples with antioxidants were decreased compared to the non-antioxidant biodiesel sample (B100). The order of antioxidant power was B100<B100T1<B100T2 = B100BHT1<B100BHT2<B100T3<B100BHT3. The solid fat content (SFC %) values were determined with different antioxidant concentrations versus different times. The minimum SFC % was determined in B100T3 and B100BHT3 in 3000 ppm antioxidant concentrations in 720 min. DSC results show that the crystallization onset temperatures for B100, B100T3, and B100BHT3 were −51.83 °C, −53.59 °C, and −54.15 °C, respectively. The kinetics of crystallization was determined and k and n values were calculated. The addition of thyme oil extract as a natural antioxidant has a positive effect on biodiesel oxidative stability for all concentrations.

Simulation of the properties of a frying composition based on ostrich oil and СО2-marjoram extract

The article reveals the optimization of a fat frying composition formulation based on ostrich oil and natural stabilizing additive using mathematical modeling of its component composition and analysis of the qualitative characteristics of the product. The object of the research was experimental versions of the frying composition obtained according to the developed recipes, which included liquid and solid fraction of ostrich oil in the following ratio, wt. %: 30,0–70,0 – the liquid one, 30,0–70,0 the solid one and 0,01–0,20 CO2 -marjoram extract. The selection and ratio of the components of the frying fat recipe was carried out using the mathematical modeling methods based on the Scheffe-simplex lattice design. A comparative analysis of the consumer properties of the fat frying composition was carried out using E.K. Harrington’s desirability function. It was shown that the best technological and qualitative characteristics of the properties of the fat frying composition were established at a ratio of 0,5 percent of liquid or 0,5 solid fractions of the frying composition mass with the addition of at least 0,1 wt. % CO2 -extract of marjoram. Positive results were also noted in samples with a minimum solid fat content of 30,0 wt. %, but with a significant amount of a stabilizing additive – 0,15 wt. %. The inhibiting effect of the introduced natural additive, which slowed down oxidative processes in the process of frying the product, were proven. It was determined that only experimental versions of deep-frying fat in the established optimum of the quantitative ratio of fractions and CO2 - extract had the highest desirability scores of 0,723 and 0,792, confirming the high level of product quality. In addition, the proposed combination of ingredients provided an increase in the time of use of the deep-frying composition, due to the increased resistance to oxidation.

Thermal and chemical characterization of fractions from Syagrus romanzoffiana kernel oil

The Jerivá (Syagrus romanzoffiana) kernel oil (JKO) has a pleasant coconut-like smell, with about 33% lauric acid and 28% oleic acid. The oil also contains bioactive compounds, such as phenolics, carotenoids, and tocopherols. JKO has a solid consistency at low temperatures, but has a low melting point and low solid content at room temperature. Thus, this work aimed to evaluate the thermal properties related to crystallization and fusion, as well as the chemical and oxidative characteristics of JKO fractions, olein and stearin, obtained from dry and solvent fractionation. In general, stearins had higher crystallization and melting temperatures, and higher solid fat content, unlike oleins, which may be associated with the concentration of high melting triglycerides in the stearins. No statistically significant difference was found for fatty acid profile or oxidative stability of the fractions. The type of fractionation influenced the chemical and thermal properties of JKO fractions. The solvent process promoted the most relevant differentiation of fractions. An olein was obtained with 7% less solid fat at 25 °C which remained visually liquid at 2 °C below the oil, as well as a stearin with 17% more solid fat at 25 °C which remained visually solid at 3 °C above the oil.

Development and Evaluation of Palm-based Tibetan Butter Equivalent: Formulation, Rheology, Texture and Microstructure

Palm-based Tibetan butter equivalent was developed and evaluated from formulation, rheology, texture to microstructure. Firstly, the compatibility of palm stearin and palm olein was ascertained. The formulations of palm-based Tibetan butter equivalent were then optimally developed using a combination of palm stearin (37.5%), palm olein (37.5%) and soybean oil (25%). These were found to contain high unsaturated fatty acids and analogous solid fat content (SFC) at varying temperatures. Moreover, the palm-based Tibetan butter equivalent (TBE) showed a shear-thinning behavior, a gel characteristic, good plasticity and comparable texture characteristics (such as hardness, adhesion, cohesiveness and elasticity) to traditional Tibetan butter (TB). Furthermore, as determined by polarized light microscopy (PLM) and confocal laser scanning microscopy (CLSM), the microstructures also showed a similar structure, thus further indicating that palm oil is a good candidate as a substitute in making Tibetan-style butter. Overall, the palm-based Tibetan butter equivalent was developed by physical technology and could assist in increasing the enjoyable population as well as addressing the challenge of resource shortage, geographical origin and season of production.

Development of a Caramel-Based Viscoelastic Reference Material for Cutting Tests at Different Rates

Cutting speed plays a crucial role for the behavior during and the final quality of viscoelastic foods after cutting and is, in industrial applications, usually adjusted on an empirical basis. Although previous studies investigated the interplay between the time-dependent properties and cutting behavior of model systems on an elastomer basis, there is still a need to elaborate such cause-effect relations for real foods. The aim of this study was to establish a reproducible manufacture of model caramels on a laboratory scale and to investigate the influence of the compositional parameters, moisture, and solid fat content, as well as cutting speed, on cutting behavior. It was possible to visualize ductile-brittle transitions in cutting force profiles, with an increase in cutting speed resulting in effects similar to that induced by a decreasing moisture content or an increasing solid fat content. Quantitatively, the progression of both maximum force and cutting energy reversed when cutting speed increased and composition changed in favor of a more brittle behavior. This work provides the basis for further research on distinct loading phenomena observed during the cutting of foods and for numerical modeling of the cutting process.

Preparation of Low-Diacylglycerol Cocoa Butter Equivalents by Hexane Fractionation of Palm Stearin and Shea Butter

Herein, we prepared 1,3-dipalmitoyl-2-oleoyl glycerol (POP)-rich fats with reduced levels of diacylglycerols (DAGs), adversely affecting the tempering of chocolate, via two-step hexane fractionation of palm stearin. DAG content in the as-prepared fats was lower than that in POP-rich fats obtained by previously reported conventional two-step acetone fractionation. Cocoa butter equivalents (CBEs) were fabricated by blending the as-prepared fats with 1,3-distearoyl-2-oleoyl glycerol (SOS)-rich fats obtained by hexane fractionation of degummed shea butter. POP-rich fats achieved under the best conditions for the fractionation of palm stearin had a significantly lower DAG content (1.6 w/w%) than that in the counterpart (4.6 w/w%) prepared by the previously reported method. The CBEs fabricated by blending the POP- and SOS-rich fats in a weight ratio of 40:60 contained 63.7 w/w% total symmetric monounsaturated triacylglycerols, including 22.0 w/w% POP, 8.6 w/w% palmitoyl-2-oleoyl-3-stearoyl-rac-glycerol, 33.1 w/w% SOS, and 1.3 w/w% DAGs, which was not substantially different from the DAG content in cocoa butter (1.1 w/w%). Based on the solid-fat content results, it was concluded that, when these CBEs were used for chocolate manufacture, they blended with cocoa butter at levels up to 40 w/w%, without distinctively altering the hardness and melting behavior of cocoa butter.

Preparation and characterization of oleogels with tallow and partially hydrolyzed tallow as organogelators

The aim of this study was to evaluate the organogelation potential of tallow fat (TF) and partially hydrolyzed tallow fat (HTF) against saturated monoglyceride (MG) and a saturated monoglyceride + diglyceride mixture (MDG) as the organogelators. TF itself created oleogel at a 30% addition level, while HTF, MG and MDG oleogels were prepared at 10% addition levels. Fatty acid composition data showed that the oleogel of HTF (HTFO) was quite similar to those of MG and MDG oleogels. Solid fat content, free fatty acidity and peroxide values were found to be in acceptable ranges for HTFO. Thermal properties, crystal morphology and X-ray diffraction patterns were also evaluated. Rheological analyses indicated that all oleogels had higher storage modulus (G´) than loss modulus (G´´). The time-sweep test showed that after applying higher shear rates, the gels re-formed at rest. Further, all oleogels maintained their gelled consistency until around 54 °C. The results suggest that HTF could be a cheap, efficient, fast melting, safe and readily available organogelator.