Bicarbonates and carbonates as antioxidants in vegetable oils at frying temperatures.

Antioxidant activity of bicarbonates and carbonates including NaHCO3 , Na2 CO3 , KHCO3 , and K2 CO3 was evaluated in soybean oil (SBO) at 180°C. KHCO3 and K2 CO3 had stronger activity than NaHCO3 and Na2 CO3 . KHCO3 (5.5 mEq/L, 0.060 wt.%) and K2 CO3 (5.5 mEq/L, 0.041 wt.%) were more effective than 0.02 wt.% tert-butylhydroquinone (TBHQ) in preventing oxidation of SBO. While the antioxidant activity of KHCO3 and K2 CO3 increased with increasing their concentrations up to 5.5 mEq/L, it decreased at 11 mEq/L. KHCO3 and K2 CO3 were also effective in preventing oxidation of other vegetable oils including avocado, canola, corn, high oleic soybean, and olive oils. Correlation tests conducted with the results from the six oils showed that KHCO3 and K2 CO3 had weak to moderate positive correlations with γ- and δ-tocopherols. In a separate study in stripped SBO, it was found that KHCO3 had a synergistic effect with α-tocopherol, but not with γ- and δ-tocopherols. KHCO3 had additive or synergistic effect with rosemary extract, epigallocatechin gallate, ascorbic acid, and ascorbyl palmitate. Antioxidant activity of KHCO3 was confirmed in frying of potato cubes in SBO and canola oil. Although more studies should be conducted for better understanding of the mechanisms and factors affecting the antioxidant activity of bicarbonates and carbonates, this study demonstrated that they could serve as antioxidants or co-antioxidants of other antioxidants in frying. PRACTICAL APPLICATION: Inorganic salts including NaHCO3 , KHCO3 , Na2 CO3 , and K2 CO3 hadstrong antioxidant activity in vegetable oils at frying temperatures when they wereadded as powder. Antioxidant activity of 0.06 wt.% KHCO3 was higherthan that of 0.02 wt.% TBHQ in soybean oil and canola oil during frying potato. KHCO3 had additive orsynergistic effect with rosemary extract, epigallocatechin gallate, ascorbicacid, and ascorbyl palmitate indicating that these inorganic salts can be usedas co-antioxidants to enhance the antioxidant activity of existing antioxidantswhile they can be used alone as well.

Texture and flavor evaluation of peanut butter stabilized with natural waxes.

Natural peanut butter was stabilized with 1.0%-2.0% (w/w) beeswax (BW), candelilla wax (CLW), rice bran wax (RBW), or sunflower wax (SFW). The appearance, spreadability, mouthfeel, and flavor attributes of these samples were evaluated by a trained sensory panel using commercial stabilized peanut butter and a sample stabilized with hydrogenated cottonseed oil as references. The waxes and their blend ratio significantly (p < 0.05) influenced appearance, spreadability, firmness, mouthfeel, and flavor attributes. Samples with 1.5%-2.0% CLW, or 1.0%-1.5% RBW had the fewest differences in appearance and texture from the reference and commercial samples. However, an off-flavor was attributed to 1.5% or higher CLW. Samples stabilized with BW or with 1.0%-1.5% RBW had the fewest difference in flavor compared to the reference sample. Overall, samples stabilized with 1.0%-1.5% RBW scored closest to the commercial and reference samples. The response of CLW, RBW, and SFW (which was only evaluated for appearance and spreadability) indicates that amounts of these waxes could be tailored in different products to achieve a product with desirable texture and flavor as well as stability to oil loss. PRACTICAL APPLICATION: This research provides information that could be used by food companies that make seed or nut butters as spreads or as ingredients for use in foods. It shows the impact of the use of four types of waxes as stabilizers, at commercially relevant levels (< 3.0%), and at levels previously shown to be effective for stabilization, on the firmness, spreadability, and other texture and flavor attributes, and thus provides a starting point for optimization for commercial product specifications.

Properties of margarines prepared from soybean oil oleogels with mixtures of candelilla wax and beeswax.

The aim of this study was to examine the physical properties of margarines prepared from oleogels with binary mixtures of candelilla wax (CDW) and beeswax (BW) in soybean oil. Some of the margarines made from oleogels with mixtures of CDW and BW had higher firmness than those made with one wax. For example, a 3% wax margarine made with 25% CDW and 75% BW had significantly higher firmness (0.97 N) than those with 100% CDW (0.59 N) and with 100% BW (0.11 N). Differential scanning calorimetry (DSC) and solid fat content (SFC) analyses revealed eutectic melting properties for binary wax margarines, which may be desirable since wax oleogel-based margarines often have higher melting points than conventional margarines. For example, the major melting point of 3% wax margarine made with 50% CDW and 50% BW was 43.85 °C, while for margarines made with 100% CDW or 100% BW, the melting points were at 46.00% and 47.61 °C, respectively. SFC was lowest for margarines with 50 or 75% BW; for example, 3% wax margarine with 25% CDW and 75% BW had 0.72% SFC at 40 °C while those with 100% CDW and 100% BW had 1.19 and 1.13% SFC, respectively. However, dropping point constantly decreased with increasing BW ratios. This study demonstrated that by mixing two waxes, the firmness of oleogel-based margarines could be increased, and the melting point could be tailored by the ratio of two waxes. PRACTICAL APPLICATION: This study demonstrated that firmness and melting properties of margarines prepared from wax-oleogels can be improved by mixing two waxes, making their practical application more feasible. Firmness of margarines prepared with oleogels of binary mixtures of candelilla wax and beeswax were higher than those with pure waxes. The melting point of wax oleogel-based margarines was decreased by use of binary mixtures of candelilla wax and beeswax.

The thermal, rheological, and structural characterization of grapeseed oil oleogels structured with binary blends of oleogelator.

Combination of oleogelators has recently started to receive scientific attention since single oleogelator may not adequately compensate for the diverse roles of solid fat in a complicated food system. In this study, grapeseed oil oleogels were prepared with candelilla wax (CDW) and glyceryl monostearate (GMS) blends at varying mass ratios (100:0, 75:25, 50:50, 25:75, and 0:100 [w/w]), and their physicochemical characteristics were characterized in terms of thermal, rheological, and microstructural properties. The oleogel with CDW and GMS at a blending ratio of 75 and 25 (CDW-75:GMS-25) exhibited the lowest melting point, implying a eutectic behavior. The CDW-75:GMS-25 oleogel also had a harder texture, greater viscoelasticity, and lower oiling-off characteristics that were highly attributed to its small crystals and dense structural network observed from phase-contrast microscopic images. When GMS from different vendors were examined for melting behavior and hardness of oleogels, it was found that the oleogel properties were highly dependent on the detailed composition of GMS. NMR study showed that the ternary system of CDW, glyceryl 1-monostearate, and glyceryl 1,3-distearate was responsible for the eutectic behavior of the CDW-75:GMS-25 oleogel. This study reports the unique and improved melting and physical properties of oleogels with the mixture of CDW and GMS, which can increase the feasibility of the oleogel technology in actual food products. However, caution should be taken in selecting the oleogelators because their detailed composition and properties can vary depending on sources and processing conditions. PRACTICAL APPLICATION: Increasing attention has been paid to the combination of oleogelators since single oleogelator may not adequately compensate for the diverse roles of solid fat in a complicated food system. This study showed new eutectic characteristics at a specific blending ratio of candelilla wax and glyceryl monostearate that could be positively correlated with the increased hardness, viscoelasticity, and oiling-off features. The results may encourage the food industry to utilize this binary oleogelator blend as an alternative to solid fat high in saturated fat by providing new functional properties.

Changes in markers of lipid oxidation and thermal treatment in feed-grade fats and oils.

BACKGROUND: Oxidized feed lipids have been shown to have detrimental effects on food animal growth and metabolism. The present study aimed to measure classes of lipid oxidation products (LOP) in feed-grade oils at temperatures representing production and storage conditions. RESULTS: There were significant oil type × time interactions in the accumulation of primary and secondary LOP. At 22.5 °C, peroxide value (PV), a marker for the primary phase of lipid oxidation, increased most in fish oil (FO), followed by tallow (TL), soybean oil (SO), linseed oil (LO) and modified algae oil (MAO), whereas palm oil (PO) showed no appreciable increase in PV. Secondary LOP, such as p-anisidine value, hexanal, 2,4,-decadienal, polymerized triacylglycerols and total polar compounds, increased only in FO. At 45 °C, FO and SO produced both primary and secondary LOP, whereas MAO, PO and TL had slower rates of PV increase and no secondary LOP. At 90 °C and 180 °C, all oils except for FO accumulated both primary and secondary LOP. CONCLUSIONS: Higher polyunsaturated fatty acid:saturated fatty acid oils and higher temperatures produced greater quantities of primary and secondary LOP. However, unrefined TL was more prone to oxidation at 22.5 °C than predicted, whereas LO was more stable than predicted, indicating that pro-oxidant and antioxidant compounds can markedly influence the rate of oxidation. Measuring both primary and secondary LOP will provide better information about the oxidative status of feed oils and provide better information about which classes of LOP are responsible for detrimental health effects in animals. Published 2020. This article is a U.S. Government work and is in the public domain in the USA.

Investigation of polymers and alcohols produced in oxidized soybean oil at frying temperatures.

Although significant amounts of polymers associated with adverse health effects in oils are produced during frying, the chemical bonds forming these polymers are not well understood. This study revealed that ester bonds are responsible for the polymerization of soybean oil during frying and heating at 175 °C. The ester value of soybean oil increased during frying up to day 3 of the experiment and slightly decreased on day 4 of the experiment indicating that esterification and hydrolysis concomitantly occurred. The 13C NMR spectra showed further evidence of the formation of ester bonds. This study also examined unidentified chemical bonds in the polymer products, other than ester bonds, with NMR spectroscopy. No NMR signals indicating ether bonds were observed. The NMR study after the reaction of oxidized soybean oil with acetyl chloride clarified assignments of proton signals, confirming some previous assignments, and assigning a new proton signal as an alcohol.

Study on Antioxidant Activity of Amino Acids at Frying Temperatures and Their Interaction with Rosemary Extract, Green Tea Extract, and Ascorbic Acid.

Some amino acids have strong antioxidant activity in frying oil. This study aimed to obtain further information including antioxidant activity at different concentrations and interactions with rosemary extract, green tea extract, and ascorbic acid. Antioxidant activity of arginine, cysteine, lysine, methionine, and tryptophan was examined by increasing the concentration in soybean oil (SBO) at 180 °C within the concentration range of 0 to 15 mM. These amino acids showed increased activity with increasing concentration without showing prooxidant activity at the given concentration range. Addition of 15 mM methionine did not inhibit the prooxidant activity of α-tocopherol at high concentrations in SBO while it significantly increased the activity at each concentration of α-tocopherol. Methionine showed an additive effect with a commercial rosemary extract while lysine had an antagonistic interaction in SBO at the total concentration of 5.5 mM. Mixtures of green tea extract and methionine did not show better activity than methionine alone in SBO and stripped SBO. (-)-Epigallocatechin gallate, the major active component in green tea, showed a synergistic effect with methionine in stripped SBO but there was no significant interaction effect in SBO. Although ascorbic acid had a synergistic effect with methionine in stripped SBO, it showed a significant antagonistic effect in SBO. Methionine had strong antioxidant activity in six other vegetable oils showing a moderate correlation (R2 = 0.45 to 0.52) with the ratio of unsaturated fatty acids to saturated fatty acids indicating the effectiveness may be related to the fatty acid composition of oil. PRACTICAL APPLICATION: Some amino acid such as methionine and lysine showed stronger antioxidant activity than the leading commercial natural antioxidant, rosemary extract. These amino acids showed great potential as a natural antioxidant in frying. The price of food-grade L-methionine is generally lower than rosemary extract and green tea extract. This paper provides information on the concentration effect and interactions with currently used antioxidants such as tocopherols, rosemary extract, green tea extract, and ascorbic acid.

Solubilization of cashew gum from Anacardium occidentale in aqueous medium.

Although cashew gum (CG) is known to be soluble in water, the solubilized CG does not exist as individual molecules in its solution. Instead, CG molecules form aggregates resulting in a turbid solution. For better solubilization of CG in water, two types of approaches are attempted: thermal degradation and changing the pH of solution medium. The thermal degradation at high temperatures does not follow the same pattern as a similar polysaccharide, starch: instead of being thermally degraded to smaller molecules that are readily soluble in water, the aggregated CG molecules were not fully disintegrated to individual molecules even after the heating to 190 °C. Size Exclusion Chromatography (SEC) shows that CG exists as entangled aggregates in aqueous solution at room temperature, and these aggregates disentangle in neutral or alkaline medium. Therefore, raising the pH of solution turns out to be a more efficient way to dissolve CG in water than thermal degradation. CG aggregates disintegrate only when the pH of its solution is adjusted to higher than 6.2. The peak MW of CG is measured to be 28 kDa. The lowest temperature that will initiate the thermal degradation and the temperature that induces full degradation of CG are estimated from the SEC chromatogram of heat-treated CG's.

Stability and Antioxidant Activity of Annatto (Bixa orellana L.) Tocotrienols During Frying and in Fried Tortilla Chips.

Annatto tocotrienols (AnT3), which contain approximately 90% δ-tocotrienol (δ-T3), were added to mid-oleic sunflower oil used for frying tortilla chips over 3 d. The objectives were to evaluate their stability during frying, absorption by the fried food, and activity as antioxidants in frying oil and in tortilla chips during storage. AnT3 did not significantly affect the stability of the oil during frying or the sensory profiles of freshly fried chips. The naturally present α-tocopherol (α-T) in the oil degraded at a lower rate in the presence of AnT3, resulting in significantly higher α-T by the end of the frying study. Levels of tocopherols and tocotrienols in the chips mirrored oil levels. AnT3 did not affect the sensory profile of the chips after 1 wk of storage at 50 °C, but after 3 wk of storage, the control chips had higher levels of painty and rancid flavors compared to chips with AnT3. Headspace hexanal was also significantly higher in the control chips compared to the chips with AnT3 after 3 wk of storage. PRACTICAL APPLICATION: Annatto tocotrienols, containing primarily delta- and gamma-tocotrienols, were added to mid-oleic sunflower oil used for frying tortilla chips. The tocotrienols were absorbed by the chips along with the oil. They slowed the degradation of α tocopherol during frying, and reduced levels of painty and rancid flavor scores as well as headspace hexanal in chips that were stored for 3 wk at elevated temperatures. The results indicated that fried snack foods such as tortilla chips may be a suitable and convenient vehicle for enriching tocotrienols in the diet, and that tocotrienols may also enhance the shelf-life of fried foods.

Utilization of Oleogels as a Replacement for Solid Fat in Aerated Baked Goods: Physicochemical, Rheological, and Tomographic Characterization.

Canola oil-carnauba wax oleogels were evaluated as a replacement for shortening in a baked cake system. The use of oleogels produced cake batters with a lower pseudoplastic property and also contributed to their viscous nature. The shortening replacement with oleogels at up to 50% was effective in maintaining the ability to hold air cells into the cake batters. The volume of cakes had an overall tendency to decrease with increasing shortening replacement with oleogels, leading to increased cake firmness. The tomographic analysis demonstrated that the total porosity and fragmentation index were reduced in the oleogel cakes, showing a more connected solid structure. The levels of saturated fatty acids in the cakes containing oleogels were significantly reduced to 13.3%, compared to the control with shortening (74.2%). As a result, the use of oleogels for shortening up to 25% produced cakes with lower levels of saturated fatty acids without quality loss.

Antioxidant activity of amino acids in soybean oil at frying temperature: Structural effects and synergism with tocopherols.

The purpose of this study was to evaluate amino acids as natural antioxidants for frying. Twenty amino acids were added to soybean oil heated to 180°C, and the effects of amino acid structure on the antioxidant activity were investigated. Amino acids containing a thiol, a thioether, or an extra amine group such as arginine, cysteine, lysine, methionine, and tryptophan had the strongest antioxidant activities. At 5.5mM, these amino acids had stronger antioxidant activities than 0.02% (1.1mM) tert-butylhydroquinone (TBHQ). A functional group such as an amide, carboxylic acid, imidazole, or phenol appeared to negatively affect amino acid antioxidant activity. Synergism between amino acids and tocopherols was demonstrated, and we found that this synergistic interaction may be mostly responsible for the antioxidant activity that was observed. In a frying study with potato cubes, 5.5mM l-methionine had significantly stronger antioxidant activity than 0.02% TBHQ.

Properties of Cookies Made with Natural Wax-Vegetable Oil Organogels.

The aim of this study was to examine the feasibility of cookies in which the conventional margarine is replaced with an organogel of vegetable oil (VO) and natural wax. New cookies from VO organogels contain no trans fats and much less saturated fats than cookies made with a conventional margarine. To understand the effects of different kinds of waxes, organogels were prepared from 4 different waxes including sunflower wax (SW), rice bran wax (RBW), beeswax, and candelilla wax and properties of cookie dough and cookie were evaluated. To investigate the effects of different VOs on the properties of cookies, 3 VOs including olive oil, soybean oil and flaxseed oil representing oils rich in oleic acid (18:1), linoleic acid (18:2), and linolenic acid (18:3), respectively, were used. Both the wax and VO significantly affected properties of organogel such as firmness and melting behavior shown in differential scanning calorimetry. The highest firmness of organogel was observed with SW and flaxseed oil. Properties of dough such as hardness and melting behavior were also significantly affected by wax and VO while trends were somewhat different from those for organogels. SW and RBW provided greatest hardnesses to cookie dough. However, hardness, spread factor, and fracturability of cookie containing the wax-VO organogel were not significantly affected by different waxes and VOs. Several cookies made with wax-VO organogels showed similar properties to cookies made with a commercial margarine. Therefore, this study shows the high feasibility of utilization of the organogel technology in real foods such as cookies rich in unsaturated fats.

Evaluation of canola oil oleogels with candelilla wax as an alternative to shortening in baked goods.

The oleogels of canola oil with candelilla wax were prepared and utilized as a shortening replacer to produce cookies with a high level of unsaturated fatty acids. The incorporation of candelilla wax (3% and 6% by weight) to canola oil produced the oleogels with solid-like properties. The firmness of the oleogels was lower than that of the shortening at room temperature. A more rapid change in the viscosity with temperature was observed with increasing levels of candelilla wax in the steady shear measurements. The replacement of shortening with oleogels in the cookie formulation reduced both viscoelastic parameters (G' and G") of the cookie doughs. The level of unsaturated fatty acids in the oleogel cookies was distinctly increased up to around 92%, compared to the shortening cookies (47.2%). The cookies with the oleogels showed desirable spreadable property and the replacement of shortening with the oleogels produced cookies with soft eating characteristics.

Synthesis of steryl ferulates with various sterol structures and comparison of their antioxidant activity.

Steryl ferulates synthesised from commercial sterols as well as commercial oryzanol were used to better understand how structural features affect antioxidant activity in vitro by the ABTS(+) radical decolorization assay, by oxidative stability index (OSI) of soybean oil, and by analysis of antioxidant activity during frying. Steryl ferulates inhibited the ABTS(+) radical by 6.5-56.6%, depending on their concentration, but were less effective, especially at lower concentrations, than ferulic acid. Ferulic acid and steryl ferulates had either no effect, or lowered the OSI of soybean oil by up to 25%, depending on the concentration. In their evaluation as frying oil antioxidants, steryl ferulates with a saturated sterol group had the best antioxidant activity, followed by sterols with one double bond in the C5 position. The results indicate that a dimethyl group at C4 as well as a C9,C19 cyclopropane group, as found in oryzanol, negatively affects antioxidant activity in frying oils.

Enhancing antioxidant activity of sesamol at frying temperature by addition of additives through reducing volatility.

Additives were evaluated to investigate their effects on volatility of sesamol at frying temperature with the hypothesis that the interaction between an additive and sesamol would reduce sesamol volatility. Twenty-two additive : sesamol combinations were examined by thermogravimetric analysis (TGA) under nitrogen in neat form and in soybean oil. The results indicate that these additives could bind to or interact with sesamol and consequently reduced its volatility. (1) H NMR study provided evidence for hydrogen bonding between sesamol and a hydroxyl group, an amino group, and ether groups. Subsequent heating tests were conducted to investigate the effect of the reduced volatility of sesamol on antioxidant activity in soybean oil at 180 °C. Oxidation of soybean oil was monitored with gel permeation chromatography for formation of polymerized triacylglycerols and with (1) H NMR for loss of olefinic and bisallylic protons. Sesamol retained in soybean oil during the heating process was determined by high-performance liquid chromatography. A strong correlation between the retained sesamol and the antioxidant activity was observed. The mixture of 830 ppm sesamol and mono-/diglycerides, polysorbate 20 or l-carnosine showed much improved antioxidant activity compared to sesamol itself and slightly better antioxidant activity than 200 ppm tert-butylhydroquinone. It is believed that this method can also be used for many other antioxidants for which volatility is a problem.

Preparation of margarines from organogels of sunflower wax and vegetable oils.

UNLABELLED: It was previously reported that sunflower wax (SW) had high potential as an organogelator for soybean oil-based margarine and spread products. In this study, 12 other vegetable oils were evaluated in a margarine formulation to test feasibility of utilization of SW as an alternative to solid fats in margarine and spread products containing these oils. The minimum quantity of SW required to form a gel with these oils ranged from 0.3% to 1.0% (wt.). Organogels were prepared from the vegetable oils with 3%, 5% and 7% SW and were tested for firmness as well as melting behaviors using differential scanning calorimetry. These organogels were also incorporated into a margarine formulation. All of the vegetable oil organogels produced relatively firm margarines. The margarines prepared from organogels containing 3% (wt.) SW had greater firmness than commercial spreads, whereas margarines made from 7% SW were softer than commercial stick margarines. However, dropping points of the margarine samples were higher than those of commercial spread and margarine products. Margarine firmness was modestly inversely correlated with the amount of polar compounds in the oils and did not correlate with fatty acid compositions. This study demonstrates the feasibility of using a number of healthy vegetable oils rich in polyunsaturated fatty acids to make healthy margarine and spread products by utilizing SW as an organogelator. PRACTICAL APPLICATION: This study showed that sunflower wax could be used as an alternative to traditional solid fats for the development of new margarine and spread products from a variety of healthy vegetable oils.

Rigid versus flexible: how important is ligand "preorganization" for metal ion recognition by lower rim-functionalized calix[4]arenes?

For an assessment of the outcomes from use of an appropriately "preorganized" calixarene-based ionophore versus its conformationally mobile prototype, solvent extraction propensities of flexible calix[4]arene di-[N-(X-sulfonyl)carboxamides] for alkali, alkaline earth metal cations, Pb2+, Ag+ and Hg2+ are compared with those for seven new rigid analogs fixed in the cone, partial cone and 1,3-alternate conformations. For each of the metal ions, the preferred calix[4]arene conformation was determined from the NMR spectra for the metal salt of the flexible ligand. Except for Ag+, flexible calix[4]arene di-[N-(X-sulfonyl)carboxamides] were found to provide greater metal ion extraction efficiency and better selectivity than the corresponding "preorganized" ionophores.

New Proton-Ionizable Lariat Ethers with Picrylamino-Type Side Arms and Their Alkali Metal Salts. Synthesis and Structural Studies(1).

Twelve novel proton-ionizable dibenzo lariat ethers with picrylamino-type sidearms attached to the central carbon of a three-carbon bridge have been prepared in high yields by a three-step synthesis from the lariat ether alcohols via the corresponding lariat ether mesylates and amines. Structural studies conducted in solution by (1)H NMR spectroscopy and in the solid state by X-ray diffraction show that the picrylamino-type lariat ethers are preorganized for metal ion complexation with the sidearms oriented toward the macrocyclic polyether cavities due to intramolecular NH.O bonding. Structural investigations of the alkali metal salts of representative ionized picrylamino-lariat ethers in solution demonstrate cooperative coordination of the metal cation by the macrocyclic polyether unit and the ionized sidearm that serves as the counterion with the negative charge localized on the one of o-nitro groups. In the Li(+) salt of ionized sym-(picrylamino)dibenzo-14-crown-4, this places the aromatic ring of the sidearm perpendicular to the plane of the four ring oxygens.