Properties of Oleogels Formed With High‐Stearic Soybean Oils and Sunflower Wax

In an effort to develop alternatives for harmful trans fats produced by partial hydrogenation of vegetable oils, oleogels of high‐stearic soybean (A6 and MM106) oils were prepared with sunflower wax (SW) as the oleogelator. Oleogels of high‐stearic oils did not have greater firmness when compared to regular soybean oil (SBO) at room temperature. However, the firmness of high‐stearic oil oleogels at 4 °C sharply increased due to the high content of stearic acid. High‐stearic acid SBO had more polar compounds than the regular SBO. Polar compounds in oil inversely affected the firmness of oleogels. Differential scanning calorimetry showed that wax crystals facilitated nucleation of solid fats of high‐stearic oils during cooling. Polar compounds did not affect the melting and crystallization behavior of wax. Solid fat content (SFC) showed that polar compounds in oil and wax interfered with crystallization of solid fats. Linear viscoelastic properties of 7% SW oleogels of three oils reflected well the SFC values while they did not correlate well with the firmness of oleogels. Phase‐contrast microscopy showed that the wax crystal morphology was slightly influenced by solid fats in the high‐steric SBO, A6.     

Physical properties of shortenings with low‐trans fatty acids as affected by emulsifiers and storage conditions

The quality of shortenings, such as solid fat content (SFC) and texture, strongly depends on temperature fluctuations during storage and handling. The quality of a shortening might be affected not only by temperature fluctuations but also by its chemical composition and the presence of emulsifiers. The objective of this work was to investigate the effect of emulsifier addition and storage conditions on the texture, thermal behavior and SFC of low‐trans shortenings formulated with palm oil, palm kernel oil, and vegetable oils such as sunflower and soybean oils. Several conclusions can be drawn from this study: (a) The crystallization behavior of fat blends strongly depends on the type of emulsifier used and the chemical composition of the sample; (b) the addition of emulsifiers affects not only the type of crystals formed (fractionation) but also the amount of crystals obtained (enthalpy, SFC), inducing or delaying the crystallization process; (c) emulsifiers affect the texture of the crystalline structure formed by making it softer; (d) the storage conditions affect both the texture and the SFC of the materials. This study shows that samples that are highly super‐cooled during storage become harder while samples that are less super‐cooled become softer with storage conditions.     

The influence of food emulsifiers on fat and sugar dispersions in oils. III. Water content,purity of oils

The influence of water on the interactions between fat and sugar crystals dispersed in triglyceride (vegetable) oils was qualitatively estimated from sedimentation and rheological experiments. The experiments were performed both with and without food emulsifiers (monoglycerides and lecithins) present in the oil. The effects of minor natural oil components (nontriglycerides) on the interactions and on emulsifier adsorption to the crystals were examined by comparing a commercial refined oil and a chromatographically purified oil. The results show that water generally increases the adhesion between fat and sugar crystals in oils and also increases the surface activity of the oil-soluble food emulsifiers. Minor oil components give a small increase in the adhesion between fat and sugar crystals in oils, but do not influence the adsorption of food emulsifiers in any systematic way.     

Interfacial Crystallization of Diacylglycerols Rich in Medium‐ and Long‐Chain Fatty Acids in Water‐in‐Oil Emulsions

The effects of diacylglycerols rich in medium‐ and long‐chain fatty acids (MLCD) on the crystallization of hydrogenated palm oil (HPO) and formation of 10% water‐in‐oil (W/O) emulsion are studied, and compared with the common surfactants monostearoylglycerol (MSG) and polyglycerol polyricinoleate (PGPR). Polarized light microscopy reveals that emulsions made with MLCD form crystals around dispersed water droplets and promotes HPO crystallization at the oil‐water interface. Similar behavior is also observed in MSG‐stabilized emulsions, but is absent from emulsions made with PGPR. The large deformation yield value of the test W/O emulsion is increased four‐fold versus those stabilized via PGPR due to interfacial crystallization of HPO. However, there are no large differences in droplet size, solid fat content (SFC), thermal behavior or polymorphism to account for these substantial changes, implying that the spatial distribution of the HPO crystals within the crystal network is the driving factor responsible for the observed textural differences. MLCD‐covered water droplets act as active fillers and interact with surrounding fat crystals to enhance the rigidity of emulsion. This study provides new insights regarding the use of MLCD in W/O emulsions as template for interfacial crystallization and the possibility of tailoring their large deformation behavior. Practical Applications: MLCD is applied in preparing W/O emulsion. It is found that MLCD forms unique interfacial Pickering crystals around water droplets, which promote the surface‐inactive HPO nucleation at the oil‐water interface. Thus MLCD‐covered water droplets act as active fillers and interact with surrounding fat crystals, which can greatly enhance the rigidity of emulsion. This observation would provide a theoretical reference and practical basis for the application of the MLCD with appreciable nutritional properties in lipid‐rich products such as whipped cream, shortenings margarine, butter and ice cream, so as to substitute hydrogenated oil. MLCD‐stabilized emulsions can also be explored for the development of novel confectionery products, lipsticks, or controlled release matrices.     

Phylloquinone (vitamin K1) and dihydrophylloquinone content of fats and oils

Assessment of vitamin K (VK) dietary intakes has been limited by the incompleteness of VK food composition data for the U.S. food supply, particularly for VK-rich oils. The phylloquinone (VK-1) and 2′,3′-dihydrophylloquinone (dK) concentrations of margarines and spreads (n=43), butter (n=4), shortening (n=4), vegetable oils (n=6), and salad dressings (n=24) were determined by RP-HPLC with fluorescence detection. Each sample represented a composite of units or packages obtained from 12 or 24 outlets, which were geographically representative of the U.S. food supply. Butter, which is derived from animal fat sources, had less VK-1 compared to vegetable oil sources. The VK-1 and dK of the margarines and spreads increased with fat content and the degree of hydrogenation, respectively. In some margarines or spreads and in all shortenings, the dK concentrations were higher than the corresponding VK-1 concentrations. As the fat content of salad dressings increased, the VK-1 concentrations also increased. Fat-free foods had <1 μg/100 g of either form of the vitamin. No dK was detected in the salad dressings or oils tested. Some margarines, spreads, and salad dressings may be significant sources of vitamin K in the U.S. food supply.     

Application of Indirect Enzymatic Method for Determinations of 2-/3-MCPD-Es and Gly-Es in Foods Containing fats and Oils

Because of the potential health risks, fatty acid esters of 3‐chloro‐1,2‐propanediol (3‐MCPD‐Es), 2‐chloro‐1,3‐propanediol (2‐MCPD‐Es) and glycidol (Gly‐Es) in foods are drawing the attention of public health authorities. To assess applicability of the rapid indirect method developed earlier by using a Candida rugosa lipase for the analyses of refined fats and oils was applied to the analyses of various foods. Mayonnaise, vegetable oil margarine and fat spread could be analyzed with the hydrolysis condition of 30 min at room temperature. Analyses of 3‐MCPD‐Es in margarines and fat spreads containing milk fat could be analyzed by increasing the hydrolysis temperature to 40 °C. The results in a mayonnaise, four fat spreads and five margarines analyzed by the enzymatic method were 0.10–0.98 mg/kg for 3‐MCPD, 0.05–0.41 mg/kg for 2‐MCPD and 0.15–0.59 mg/kg for Gly, and correlated well with the results obtained by AOCS Cd 29a with Cd 30–15 with slopes of 0.99–1.13, and R²s of 0.87–0.99. Further, by adding a simple fat extraction step using a solvent mix at 60 °C, foods high in protein and carbohydrate, such as infant formulas, could also be successfully analyzed with >90 % recovery in 1 day. Because the enzymatic method requires only 30 min for hydrolysis, the method is considered suitable for routine analyses of 2‐/3‐MCPD‐Es and Gly‐Es in foods.     

Effect of Different Frying Methods on the Total <Emphasis Type="Italic">trans</Emphasis> Fatty Acid Content and Oxidative Stability of Oils

The main objective of this study was to determine the effect of different frying oils and frying methods on the formation of trans fatty acids and the oxidative stability of oils. Sunflower, canola and commercial frying oils, the most commonly used oils for frying potatoes in the fast food industry, were used as the frying medium. The value for total polar compounds was highest when commercial frying oil was used in the microwave oven (22.5 ± 1.1). The peroxide value, as an indicator of oil oxidation, was lowest for microwave oven frying (2.53 ± 0.03). The K₂₃₂ and K₂₇₀ values were 0.41 ± 0.04 and 0.18 ± 0.02, respectively, for commercial frying oil in the microwave oven. The lowest free fatty acid content was recorded for the commercial frying oil used in the deep‐fat fryer at 190 °C. The highest iodine value was measured for sunflower oil used in the deep‐fat fryer (148.14 ± 0.07), indicating a greater degree of unsaturation. The lowest trans fatty acid value was recorded for sunflower oil in the microwave oven (0.17 ± 0.05), with a higher overall amount of total trans fatty acids observed for oils after frying in the electrical deep‐fat fryer compared to the microwave. Sunflower oil was favourable for both frying methods in terms of the trans fatty acid content.     

In Situ Observation and Physical–Chemical Characteristics of Rambutan (Nephelium lappaceum L.) Kernel Olein Crystals Obtained from Acetone Fractionation

Hard fat stocks containing highly saturated fats are a necessary ingredient for fabrication of trans-free plastic fats. Crystal fractions obtained from the fractionation of fats naturally containing saturated fatty acids (SFA) may be a promising approach to produce the desired hard fat stocks. Influences of cooling rate (0.4, 2.0 and 10.0 °C·min⁻¹) and fractionation temperature (15 and 20 °C) on the formation of solid fat crystals of rambutan (Nephelium lappaceum L.) kernel olein (RKOle) during acetone fractionation were examined using in situ observation with polarized light microscopy (PLM). The resulting stable crystals were then separated and characterized by their iodine values, fatty acid compositions, crystal polymorphism, solid fat index, and melting behavior. PLM results showed that cooling rate affected crystal formation. Entrained oil on the surface and number of small crystals increased at higher cooling rates of RKOle. Stable crystals were obtained at a cooling rate of 2.0 °C·min⁻¹ and 6 hours, which had lower iodine value and contained more SFA with a higher amount of solid fat than incipient RKOle. Crystals fractionated at 20 °C were larger in size, fewer in number, and had less entrained oil compared to those fractionated at 15 °C. Their main polymorph was the β' form with a melting range comparable to common fully hydrogenated oils. Results suggested that RKOle crystals have potential for use as hard fat stocks for various purposes.     

Tripalmitin-Driven Crystallization of Palm Oil: The Role of Shear and Dispersed Particles

While palm oil (PO) is a reliable ingredient in formulations for biscuits, cream fillings, and compound chocolates, our understanding of its crystallization behavior and physico-chemistry pales in comparison to many other fats and oils. Phase diagrams of triacylglycerol (TAG) mixtures may be used to elucidate fat crystal polymorphism and composition of such oils, yet conditions important to the food industry such as shear speed, relevant processing temperatures, and presence of secondary ingredients are regularly overlooked. Here, the effects of shear speed (n = 0–500 RPM), dispersion concentration (0–5 wt.%), and dispersed particle surface chemistry [silica or octadecyl-functionalized (C18) silica] on the thermal properties of commercial PO when cooled from 60 to 20 °C at 1 °C min⁻¹ were explored, with focus placed on PO's higher-melting fraction. Using a series of high-purity TAG standards, X-ray diffraction revealed PO's higher-melting fraction as mainly composed of tripalmitin (PPP) crystals and molecular compounds (MC) of PPP either with 1,3-dipalmitoyl-2-oleoyl-sn-glycerol (POP) or with POP and 1,2-dipalmitoyl-3-oleoyl-rac-glycerol (PPO) in combination, all in a double chain-length β' (i.e., β'-2) conformation. Shear increased the formation of lower-melting α-2 POP and β'-2 MC_POP:PPO:PPP crystals while depleting the system of β'-2 MC_POP:PPP and β'-2 PPP crystals. This loss was further exacerbated by the addition of dispersed particles to the point where PPP was completely incorporated as MC and β'-2 PPP crystals were eliminated. While heterogeneous nucleation tends to favor kinetic products of fat crystallization, the interactions between shear and surface chemistry varied between crystal types.     

Lecithins in oil-continuous emulsions. Fat crystal wetting and interfacial tension

Lecithin is a powerful emulsifier widely used in foods, feeds and pharmaceuticals. Several analytical methods have been proposed to characterize lecithins, but they are often inadequate to determine the industrial functionality. The purpose of this study was to find a relationship between the interfacial properties of lecithins (adsorption to oil/water and fat crystal/oil/water interfaces), phospholipid composition and functionality. Results show that all lecithins adsorb to fat crystals at the triglyceride oil/water interface, making their surface more polar (observed as an increase in the contact angle measured through the oil at the interface: fat crystal/oil/water). This adsorption process is quick (less than five minutes) for relatively polar lecithins, such as soybean phosphatidylcholine (PC), and results in highly polar surfaces (contact angle ∼180°). Less polar lecithins give slow adsorption (some hours) and less polar crystals (contact angle ≤90°). The adsorption of different lecithins to the oil/water interface, observed as a decrease in interfacial tension, follows the adsorption pattern to the fat crystals. We found a relation between high-fat crystal polarity and poor lecithin functionality in margarine (margarines spatters during frying), and also between high-fat crystal polarity and a high polar to nonpolar phospholipids [Σ(PI + PA + LPC)/ΣPE; PI, phosphatidylinositol; PA, phosphatidic acid; LPC, lysoPC, PE, phosphatidylethanolamine] ratio in lecithin. The correlations might bevia aggregation properties of lecithin in the oil. We found also that monoolein shifted the adsorption kinetics of lecithin (soybean PC) to fat crystals and the hydrophilicity of adsorbed layers probably due to formation of mixed aggregates between monoolein and soybean PC.     

Fatty Acid and Phytochemical Compositions of Plantago Seed Oils and Their Functionalities

To develop the potential applications of Plantago plants, seed oils were extracted from 14 cultivars of Plantago around China. Their fatty acid profiles, tocopherols, carotenoid compositions, anti‐inflammatory and antioxidant properties were also investigated. The Plantago seed oils (PSO) were abundant in linolenic acid from 11.12 to 29.36 g/100 g oil and had low fatty acid ratio of n‐6/n‐3 ratio matched with the dietary recommendations. The tocopherol contents of PSO ranged from 693.25 to 3708.80 μg/g and the lutein contents ranged from 2.29 to 26.68 μg/g. The PSO showed significant inhibitory effects on TNF‐α, IL‐1β, and COX‐2 mRNA expression in RAW 264.7 mouse macrophage cells induced by LPS. In addition, the properties on scavenging DPPH, oxygen and hydroxyl radicals indicated that PSO had potential antioxidant properties. The results could develop PSO as novel functional foods to improve human health.     

Chemical Compositions of Walnut (Juglans regia L.) Oils from Different Cultivated Regions in China

This study is a comprehensive report on the quality of Chinese walnut oil, which enriches the research of oil resources. A total of 16 walnut samples from China were selected, and walnut oils were obtained using the pressing process. The lipid compositions and micronutrient contents were analyzed. The fatty acids corresponded to palmitic acid (3.05–8.25%), oleic acid (12.56–26.03%), linoleic acid (51.21–68.97%), and linolenic acid (6.83–15.01%), and the main triacylglycerols were trilinolein (27.87–39.47%), followed by oleoyl‐linoleoyl‐linolenoyl‐glycerol (17.07–24.18%), dilinoleoyl‐oleoyl‐glycerol (9.65–15.46%), palmitoyl‐dilinoleoyl‐glycerol (5.96–14.98%), and dilinoleoyl‐linolenoyl‐glycerol (6.42–12.43%). In addition, high amounts of micronutrients, including phytosterol, squalene, tocopherol, and total phenolic content, were found in walnut oils ranging from 540 to 1594, 17 to 131, 345 to 1280, and 1.04 to 20.39 mg kg^?1 among different samples, respectively. The differences in the geographical location and climate caused different regions of cultivation, which resulted in the differences in the chemical composition of walnut oil. Further multiple linear regression analyses between oxidative stability indices, fatty‐acid compositions, and micronutrients revealed that linoleic acid (R = ?0.891; P < 0.05), α‐tocopherol (R = 0.713; P < 0.05), and total phenolic content (R = 0.369; P < 0.05) were the main factors that affect the oxidative stability of the walnut oil.     

Matching the Functionality of Single-Cell Algal Oils with Different Molecular Compositions

The fatty acid composition, triglyceride composition, melting/crystallization profiles, crystallization kinetics, X-ray diffraction patterns, microstructure and mechanical properties of a pair of algal oils were studied to elucidate structural reasons for the similarity in melting and mechanical properties. Oil A is a predominantly saturated fat, rich in capric, myristic and palmitic acids, composed mostly of trisaturated triglycerides while Oil B contains predominantly palmitic and oleic acids in triglycerides such as POP/OPP and OOP/OPO. The DSC thermogram of Oil A shows similar peak melting temperatures to that of Oil B with Oil B exhibiting a few additional peaks. Both oils exhibit identical SFC-temperature profiles. Polarized light microscopy revealed a needle-like morphology for both Oil A and Oil B, with an average length of approximately 3.5–4.0 μm. The similar morphology of the crystals was attributed to a similar polymorphic form (β’) present in both. The fractal dimensions for the distribution of crystalline material within the fat crystal networks of both oils were also similar. The identical melting and mechanical properties of Oil A and Oil B were thus be attributed, respectively, to the presence of different triglycerides (in approximately equal proportions) with similar melting points and the assembly of these triglycerides into crystals of identical shape and size, which are in turn assembled into a network with identical crystal mass distributions. This work suggests that the mechanical and thermal properties of oils with vastly different molecular compositions can be matched by targetting specific TAG combinations which yield similar melting behavior, microstructure and mechanical response.     

Determination of polyphenols,tocopherols, and antioxidant capacity in virgin argan oil (Argania spinosa,Skeels)

This study establishes data on polyphenols, tocopherols, and antioxidant capacity (AC) of virgin argan oil. A total of 22 samples from Morocco were analyzed. Total polyphenol content ranged between 6.07 and 152.04 mg GAE/kg. Total tocopherols varied between 427.0 and 654.0 mg/kg, being γ‐tocopherol the major fraction (84.68%); α‐, β‐, and δ‐tocopherols represent 7.75, 0.33, and 7.29%, respectively. No influence of oil extraction method on total tocopherols was observed. The AC of argan virgin oils determined by the ABTS method in n‐hexane oils dilution ranged between 14.16 and 28.02 mmol Trolox/kg, and by the ABTS, DPPH, and FRAP methods in methanolic oil extracts between 2.31–14.15, 0.19–0.87, and 0.62–2.32 mmol Trolox/kg, respectively. A high correlation was found between ABTS and DPPH methods applied to a methanolic oil extract. Virgin argan oil presents a higher polyphenol and tocopherol content, and total AC than other edible vegetable oils.     

Chemical Characterization of Virgin Almond and Hazelnut Oils and Their By‐Products

Various cultivars of almonds (“Ferragnes,” “Guara,” “Largueta,” and “Marcona”) and hazelnuts (“Negret,” “Pauetet,” and “Tonda”), particularly their virgin oils and by‐products, are evaluated in this study. The almond and hazelnut virgin oils present high contents of oleic acid (59–73% and 76–80%, respectively) and α‐tocopherol (420–542 and 310–378 mg kg^–1, respectively), as compared with other virgin vegetable oils. Aldehydes are the major contributors to their aromatic profile (54–74% almond oil and 30–40% hazelnut oil of total content), especially, benzaldehyde in almond oils (1.35–7.52 mg kg^–1), and hexanal in hazelnut oils (0.99–1.27 mg kg^–1). Statistical differences exist between the virgin almond and hazelnut oils and their varieties, for most of the chemical compounds studied. While all the nut varieties are high in polar phenolic compounds, “Ferragnes” almonds (1262 mg kg^–1) and “Negret” hazelnuts (1720 mg kg^–1) stand out. Accordingly, high antioxidant activity is also observed. Finally, the residual cakes may be considered a good source of polar phenolic compounds (823–2064 mg kg^–1 almond cakes, 2261–4179 mg kg^–1 hazelnut cakes), possessing high antioxidant capacity with potential applications of these by‐products as functional ingredients in food and non‐food formulations. Practical Applications: Virgin nut oils are gaining consumers’ preference due to their unique organoleptic attributes and potential health effects. It is therefore very relevant to establish their specific chemical composition, directly related to their properties, and that are greatly affected by the cultivar.     

Chemical Compositions and Mineral Contents of Some Hull-Less Pumpkin Seed and Oils

The main objective of this study was to determine total oil, total phenol, antioxidant activity and mineral contents of hull‐less pumpkin seeds and also fatty acid composition of seed oils. The results indicated that total oil, total phenol content and antioxidant activity values were found between 33.04 and 46.97 %, 56.94 and 87.15 mg GAE/100 g and 0.19 and 11.75 %, respectively (p < 0.05). Linoleic, oleic, palmitic and stearic acids were the most prominent fatty acids in all genotypes. The most abundant mineral in the studied seeds, which belong to different genotypes, was potassium (2704.75–1033.63 ppm) followed by phosphorus (3569.690–9108.835 ppm) and magnesium (1275.15–3938.16 ppm) (p < 0.05). Particularly genotype‐1 was the richest seed in essential fatty acids and minerals.     

Detection of Extra Virgin Olive Oil Adulteration With Edible Oils Using Front‐Face Fluorescence and Visible Spectroscopies

Synchronous front‐face fluorescence and visible spectroscopies are utilized for the simple, rapid, and nondestructive quantification of extra virgin olive oil (EVOO) adulteration with corn, soybean, and sunflower oils. For each adulterant, 42 adulterated EVOO samples in the adulterant amount in the range 1.0–50 g/100 g were prepared. The partial‐least‐squares regression was executed for quantification. Both full (leave‐one‐out) cross‐validation and external validation were performed to evaluate the predictive ability. The plots of observed vs. predicted values exhibit high linearity. The coefficient of determination (R²) values are larger than 0.99. The root mean square errors of both cross‐validation and prediction are no more than 2%. The detection limits for the three seed oils using fluorescence and visible spectroscopies are in the range of 1.5–2.2% and 1.8–2.4%, respectively. The merit of this method is that both the front‐face fluorescence and visible spectroscopies are recorded toward neat oils, avoiding any sample pretreatment including dilution.     

The development and application of novel vegetable oils tailor‐made for specific human dietary needs

Conventional edible oils, such as sunflower, safflower, soya bean, rapeseed (canola) oils, were modified to obtain high‐oleic, low‐linoleic or even low‐linolenic oils. The aim was to develop salad, cooking and frying oils, that are very stable against lipid peroxidation. They are also suitable for margarine blends, as additives to cheeses and sausages, or even as feed components. Oils containing higher amounts of medium‐chain length or long‐chain polyunsaturated fish oil fatty acids are suitable as special dietetic oils or as nutraceuticals. High‐stearic oils are designed as trans‐fatty acid‐free substitutes for hydrogenated oils. New tailor‐made (designer) oils are thus a new series of vegetable oils suitable for edible purposes, where conventional oils are not suitable.     

Phenols and Volatiles of Istarska Bjelica and Leccino Virgin Olive Oils Produced with Talc,NaCl and KCl as Processing Aids

The effect of processing aids (2.5 % of talc, NaCl or KCl) on oil extractability and the profile of phenolic and volatile compounds of Istarska bjelica and Leccino oils was studied. Talc significantly increased extractability in both cultivars, while salts increased extractability in Leccino cv. In the laboratory extracted oils, phenols were determined by a RP‐HPLC–DAD method, whereas volatiles were determined by SPME/GC–MS. Talc addition significantly decreased hydroxytyrosol and increased ligstroside derivatives in produced oils, but did not affect the total phenol content. Among volatile compounds, only Z‐2‐penten‐1‐ol in Leccino and 1‐pentene‐3‐one in Istarska bjelica oils significantly increased by talc addition. Salts improved transfer of most individual phenols into oil, particularly oleuropein derivatives, and increased C6 aldehydes and C5 volatiles in Leccino oils. NaCl exerted a stronger effect in increasing individual phenols and volatiles than KCl.