Partially Hydrogenated Soybean Oil Research Articles

Comparison of Plasma Metabolome Response to Diets Enriched in Soybean and Partially-Hydrogenated Soybean Oil in Moderately Hypercholesterolemic Adults-A Pilot Study.

Partially-hydrogenated fat/trans fatty acid intake has been associated with adverse effects on cardiometabolic risk factors. Comparatively unexplored is the effect of unmodified oil relative to partially-hydrogenated fat on the plasma metabolite profile and lipid-related pathways. To address this gap, we conducted secondary analyses using a subset of samples randomly selected from a controlled dietary intervention trial involving moderately hypercholesterolemic individuals. Participants (N = 10, 63 ± 8 y, BMI, 26.2 ± 4.2 kg/m2, LDL-C, 3.9 ± 0.5 mmol/L) were provided with diets enriched in soybean oil (SO) and partially-hydrogenated soybean oil (PHSO). Plasma metabolite concentrations were determined using an untargeted approach and pathway analysis using LIPIDMAPS. Data were assessed using a volcano plot, receiver operating characteristics curve, partial least square-discrimination analysis and Pearson correlations. Among the known metabolites higher in plasma after the PHSO diet than the SO diet, the majority were phospholipids (53%) and di- and triglycerides (DG/TG, 34%). Pathway analysis indicated upregulation of phosphatidylcholine synthesis from DG and phosphatidylethanolamine. We identified seven metabolites (TG_56:9, TG_54:8, TG_54:7, TG_54:6, TG_48:5, DG_36:5 and benproperine) as potential biomarkers for PHSO intake. These data indicate that TG-related metabolites were the most affected lipid species, and glycerophospholipid biosynthesis was the most active pathway in response to PHSO compared to SO intake.

Differing unsaturation levels of soybean oils impact the properties of peroxide‐vulcanized carbon black‐filled ethylene‐propylene‐diene monomer rubber

AbstractSoybean oils having less unsaturation than conventional soybean oil (SBO) were studied as sustainable plasticizers for ethylene‐propylene‐diene monomer (EPDM) rubber compounds vulcanized with peroxide. In EPDM formulations, part of the petroleum‐based paraffinic oil (PO) was replaced with soy‐derived plasticizers such as high oleic soybean oil (HOSO), partially hydrogenated soybean oil (PHSO), and completely hydrogenated soybean oil (HSO). The mechanical and viscoelastic properties of EPDM rubbers formulated with soy‐derived plasticizers were studied and compared with the properties of PO‐based rubber. Torque rheometry was used to study the vulcanization process and the properties of the vulcanized rubber compounds were evaluated using tensile testing, compression testing, dynamic mechanical analysis, and solvent swelling experiments. The equilibrium swelling test and examination of gel fraction demonstrated the incorporation of soy‐based process aids into the rubber network during vulcanization. It was found that soy‐derived plasticizers could partially substitute for the petroleum‐based plasticizer in EPDM compounds with minimal impact on properties. An additional benefit of the use of hydrogenated SBO is the increase of crosslink density in vulcanized rubber indicating enhanced peroxide efficiency.

Dietary soybean oil, canola oil and partially-hydrogenated soybean oil affect testicular tissue and steroid hormone levels differently in the miniature pig

The present study was conducted to examine the influence of dietary canola oil (CAN) and partially-hydrogenated soybean oil (HSO) compared to soybean oil (SOY, control) on the morphology and function of testes using miniature pigs as the test subject. Male miniature pigs were fed a diet containing 10%SOY, 9%CAN+1%SOY, or 9%HSO+1%SOY for 18 months. The scheduled autopsies revealed no abnormalities in histopathological examination of the major organs, except the testes. Atrophy of the seminiferous tubules and hyperplasia in the Leydig cells were found in the SOY and CAN groups. DNA microarray analysis indicated downregulation in the CAN and the HSO groups of genes encoding for gonadotropins in the pituitary gland and of enzymes and proteins involved in steroid hormone metabolism in the testes, compared to the SOY group. Plasma levels of sex hormones in the CAN and HSO groups tended to be higher and testosterone and dihydrotestosteorne in the HSO group were significantly higher than in the SOY group. These results demonstrate that testes are morphologically and functionally affected by the dietary oils, while the plasma steroid hormone levels do not necessarily reflect the gene expression, probably owing to feedback regulation via the gonadal hormones in the hypothalamus-pituitary-gonadal axis.

Effect of a trans fatty acid-enriched diet on biochemical and inflammatory parameters in Wistar rats.

Recent data regarding trans fatty acids (TFAs) have implicated these lipids as particularly deleterious to human health, causing systemic inflammation, endothelial dysfunction and possibly inflammation in the central nervous system (CNS). We aimed to clarify the impact of partially hydrogenated soybean oil (PHSO) with different TFA concentrations on cerebrospinal fluid (CSF), serum and hepatic parameters in adult Wistar rats. Wistar rats (n=15/group) were fed either a normolipidic diet or a hyperlipidic diet for 90days. The normolipidic and hyperlipidic diets had the same ingredients except for fat compositions, concentrations and calories. We used lard in the cis fatty acid group and PHSO in the trans fatty acid group. The intervention groups were as follows: (1) low lard (LL), (2) high lard (HL), (3) low partially hydrogenated soybean oil (LPHSO) and (4) high partially hydrogenated soybean oil (HPHSO). Body weight, lipid profiles and the inflammatory responses in the CSF, serum and liver tissue were analyzed. Surprisingly, with the PHSO diet we observed a worse metabolic response that was associated with oxidative stress in hepatic tissue as well as impaired serum and CSF fluid parameters at both PHSO concentrations. In many analyses, there were no significant differences between the LPHSO and HPHSO diets. Dietary supplementation with PHSO impaired inflammatory parameters in CSF and blood, induced insulin resistance, altered lipid profiles and caused hepatic damage. Overall, these findings suggest that fat composition is more important than the quantity of fat consumed in terms of cis and trans fatty acid diets.

Enzymatic production of trans fatty acid free fat from partially hydrogenated soybean oil (PHSO) – Theory, strategy and practicability

Development of an advanced process/production technology for healthful fats constitutes a major interest of plant oil refinery industry. In this work, a strategy to produce trans fatty acid (TFA) free (or low TFA) products from partially hydrogenated soybean oil by lipase-catalysed selective hydrolysis was proposed, where a physically founded mathematic model to delineate the multi-responses of the reaction as a function of selectivity factor was defined for the first time. The practicability of this strategy was assessed with commercial trans-selective Candida antarctica lipase A (CAL-A) as a model biocatalyst based on a parameter study and fitting to the model. CAL-A was found to have a selectivity factor 4.26 and to maximally remove 73.3% of total TFAs at 46.5% hydrolysis degree.

Predicted Changes in Fatty Acid Intakes, Plasma Lipids, and Cardiovascular Disease Risk Following Replacement of trans Fatty Acid‐Containing Soybean Oil with Application‐Appropriate Alternatives

The varied functional requirements satisfied by trans fatty acid (TFA)—containing oils constrains the selection of alternative fats and oils for use as potential replacements in specific food applications. We aimed to model the effects of replacing TFA-containing partially hydrogenated soybean oil (PHSBO) with application-appropriate alternatives on population fatty acid intakes, plasma lipids, and cardiovascular disease (CVD) risk. Using the National Health and Nutrition Examination Survey 24-hour dietary recalls for 1999–2002, we selected 25 food categories, accounting for 86 % of soybean oil (SBO) and 79 % of TFA intake for replacement modeling. Before modeling, those in the middle quintile had a mean PHSBO TFA intake of 1.2 % of energy. PHSBO replacement in applications requiring thermal stability by either low-linolenic acid SBO or mid-oleic, low-linolenic acid SBO decreased TFA intake by 0.3 % of energy and predicted CVD risk by 0.7–0.8 %. PHSBO replacement in applications requiring functional properties with palm-based oils reduced TFA intake by 0.8 % of energy, increased palmitic acid intake by 1.0 % of energy, and reduced predicted CVD risk by 0.4 %, whereas replacement with fully hydrogenated interesterified SBO reduced TFA intake by 0.7 % of energy, increased stearic acid intake by 1.0 % of energy, and decreased predicted CVD risk by 1.2 %. PHSBO replacement in both thermal and functional applications reduced TFA intake by 1.0 % of energy and predicted CVD risk by 1.5 %. Based solely on changes in plasma lipids and lipoproteins, all PHSBO replacement models reduced estimated CVD risk, albeit less than previously reported using simpler replacement models.

Fractionation of Trans from Partially Hydrogenated Soybean Oil Fatty Acids

A multi-stage, low temperature solvent fractional crystallization process was developed in this work for the removal of trans fatty acids (TFA) and saturated fatty acids in free fatty acids (FFAs) obtained from hydrolysis of partially hydrogenated soybean oil (PHSO). The effects of host solvents, concentration of FAs, crystallization temperature and time on separation of TFA and SFA were studied. Among all the three solvents examined namely acetone, hexane and ethanol, acetone proved to be promising solvent. By employing acetone as a solvent TFA can be reduced to 11.6% from an initial content of 19.5% and SFA can be drop down to 3% from an initial content of 20%, by applying stepwise crystallization temperatures from 5oC to -20oC. Crystallization temperatures lower than -30oC such as -35oC and -40oC can further lower the TFA content in liquid fraction down to 5-8% by employing acetone as a solvent. TFA content can be reduced down to 12.2% and 14%; and SFA content could be reduced to 3.3% and 3.1% from an initial content of 20% when hexane and ethanol were employed as solvents, respectively. Optimum FAs to solvent ratio was 1:5 (w/v) and with a time period of 12 h for each step of crystallization. The crystallization behavior of TFA strongly depends on the type of solvents employed and crystallization temperature, while SFA crystallization depends mostly upon temperature rather than nature of solvent. Even though total removal of TFA could not be achieved in the present study, a road map has been developed for a fractionation of TFA and SFA from partially hydrogenated oil FFAs.

Interference effects from coexisting fatty acids on elaidic acid separation by fractionating crystallization: A model study

A multi-stage temperature-programmed fractionating crystallization process was carried out to examine the effects of the presence of stearic acid (SA), oleic acid (OA), and linoleic acid (LA) on the separation of elaidic acid (EA). The results showed that the efficiency of fractionating crystallization of EA depended largely on the crystallization temperature, initial concentration of EA and presence of SA. The content of SA plays very important role for the fractionating performance. It was a characteristic observation that only when SA <2%, substantial crystallization of EA (>50% in stepwise crystal fractions) were obtained regardless of the initial concentration of SA. In general, SA induced crystallization of EA in earlier stage but delayed further crystallization of EA in later stage; the crystallization of EA was independent from co-existing OA and LA. After reduction of EA content in solution to certain extent (7–10%, at −20°C), further reduction of EA content requires much lower crystallization temperatures (<−40°C, ∼5%) with significant loss of OA, indicating the limitation of the method. Instead, SA content could be easily reduced down to low concentration (∼0.5%, at −20°C). Practical applications: Presently, development of methodologies for the removal of trans-fatty acids (TFA) from partially hydrogenated soybean oil (PHSO) is of high commercial interest. One of the strategies is to selectively release TFAs as free fatty acids from PHSO enzymatically. However, all commercially available enzymes are far away from qualified to selectively release TFAs, where there are always substantial non-trans FAs hydrolyzed simultaneously. Therefore, developing post-processing technology is requisite in order to recover those non-trans fatty acids. Thus, this model system was designed based on FA composition characteristic of PHSO, which aimed to acquire some basic data and experience that lack in available literatures, so as to serve designing efficient practical process for removing trans-fatty acid moieties from PHSO. The results from this work may be of general value to achieve a better understanding of fractionating crystallization behaviors of different FAs, relationship with individual molecular feature and property, and their interference effects, which might contribute to the design of practically feasible protocol to remove TFAs from PHSO and recover non-trans FAs at the same time.

Evaluation of the performance of Frying Oils using an ultrasonic technique

The performance of unhydrogenated soybean oil (USBO) and partially hydrogenated soybean oil (PHSBO) was evaluated by comparing their frying stability. Ultrasonic velocity was used to evaluate the oils. Measurements of free fatty acids (FFA) and total polar compounds (TPC) are typical indexes of oil degradation. Oils were heated at 180 °C for periods of 8 h per day for 4 consecutive days. The results from the ultrasonic analyses show different influences of thermo-oxidation on USBO and PHSBO. The ultrasonic measurements had strong correlations with chemical changes. Consequently, the ultrasonic method is useful to obtain information on the quality of the used frying oils.

Substitution of vegetable oil for a partially-hydrogenated fat favorably alters cardiovascular disease risk factors in moderately hypercholesterolemic postmenopausal women

Objective Compared to vegetable oils in their unmodified state, partially-hydrogenated fat is associated with less favorable effects on cardiovascular disease (CVD) risk factors. Acceptable alternatives must be adjudicated. Our objective was to assess the effect of a recent commercial fat substitution, corn oil for partially-hydrogenated soybean oil. Methods Using a double-blind cross-over design, 30 postmenopausal women ≥50 years with LDL-cholesterol concentrations ≥120 mg/dL were randomly assigned to each of two 35-day phases; all food and beverage was provided to maintain body weight. Corn or partially-hydrogenated soybean oil was incorporated throughout the diet and contributed two-thirds of fat. Primary outcomes included fasting and non-fasting lipid, lipoprotein, apolipoprotein, and fasting high sensitivity C-reactive protein (hsCRP) concentrations; secondary outcomes included fasting small dense LDL (sdLDL)-cholesterol, remnant lipoprotein cholesterol (RemLC), glycated albumin, adiponectin and immunoreactive insulin concentrations, and endogenous cholesteryl ester transfer protein (CETP) and lecithin:cholesterol acyl transferase (LCAT) activities. Results Relative to the partially-hydrogenated soybean oil enriched diet, the corn oil enriched diet resulted in lower fasting total cholesterol (7%; P < 0.0001), LDL-cholesterol (10%; P < 0.0001), VLDL-cholesterol (7%; P = 0.052), apo B (9%; P < 0.0001), lipoprotein (a) [Lp(a)] (5%; P = 0.024), sdLDL-cholesterol (17%; P = 0.001), and RemLC (20%; P = 0.007) concentrations, and no significant effect on the other outcomes. Changes in postprandial (4-h post-meal) lipid, lipoprotein and apolipoprotein concentrations were similar to the fasting state. Conclusion The replacement of partially-hydrogenated soybean oil with corn oil favorably affects a range of CVD risk factors and is an appropriate option to decrease cardiovascular disease risk factors in moderately hypercholesterolemic individuals.

Physicochemical and Rheological Properties of Crystallized Blends Containing trans‐free and Partially Hydrogenated Soybean Oil

AbstractThree vegetable oil blends, intended for formulation of high melting temperature confectionary coatings, were prepared by mixing different proportions of coconut oil, palm stearin, and either partially hydrogenated soybean oil (PH‐SBO) or native soybean oil (i.e., trans‐free SBO). The blends were crystallized under the same isothermal conditions and the crystallized systems evaluated by DSC, SFC, polarized light microscopy, and rheology under low [i.e., G′ and yield stress (σ*)] and high (i.e., creep and recovery profiles) stress forces. Overall, all trans‐free blends showed lower SFC and heat of crystallization than the ones obtained with PH‐SBO blends. These results showed that trans‐fatty acids decrease the level of structural order of the crystals, and probably also the organization of the crystal network. As a result, most of the crystallized blends with PH‐SBO showed lower σ* values and higher creep profiles (i.e., softer texture) than trans‐free blends, particularly in systems crystallized at high supercooling and blends with saturated medium chain TAG. Nevertheless, at particular crystallization temperatures some trans‐free formulations provided crystallized systems with rheological properties that would result in softer textures than the ones obtained with PH‐SBO blends. Knowledge of the rheological properties under low and high stress forces is vital when comparing the functionality of crystallized TAG systems with and without TAG with trans‐fatty acids.

Trans fatty acids in partially hydrogenated soybean oil inhibit prostacyclin release by endothelial cells in presence of high level of linoleic acid

Partially hydrogenated soybean oil (PHSBO) and natural soybean oil (SBO) were obtained from a commercial source and their fatty acids were fractionated into saturates, monoenes and diene fractions. The present study compared the effect of the total, monoene and diene fatty acid fractions of PHSBO with those of the SBO on the fatty acid composition of the cell phospholipids (PL) and the prostacyclin (PGI 2) release by endothelial cells (EC) in culture. Results showed that arachidonic acid (AA) level decreased significantly and linoleic acid (LA) significantly increased in the cells incubated with the diene fraction or the monoene fraction of PHSBO plus 18:2 at 3:1 ratio compared to the cell incubated with those fractions of SBO. These changes were attributed to the inhibition of LA conversion to AA by trans 18:1 and 18:2 isomers present in the monoene or diene fractions of PHSBO leading to a significant decrease of PGI 2 released by the cells incubated with monoene or diene fractions of PHSBO. The cells incubated with the monoene of PHSBO or SBO plus 18:2 at a 1:1 ratio showed no inhibition of LA conversion to AA and the level of AA was almost equal in their PL, but the PGI 2 released by the cells incubated with the monoene of PHSBO was significantly less than the cells incubated with the monoene of SBO. This decrease was not related to the inhibition of PGI 2 synthesizing enzymes or phospholipase (PLA 2) activities. Our data show that trans acids in PHSBO inhibited the PGI 2 release by the cells through controlling the level of AA as substrate, either by (a) inhibiting the conversion of LA to AA or (b) by shunting the free AA released by the PLA 2 action to metabolism by another pathway leaving less AA available for PGI 2 synthesis.

Stearic acid-rich interesterified fat and trans-rich fat raise the LDL/HDL ratio and plasma glucose relative to palm olein in humans

BackgroundDietary trans-rich and interesterified fats were compared to an unmodified saturated fat for their relative impact on blood lipids and plasma glucose. Each fat had melting characteristics, plasticity and solids fat content suitable for use as hardstock in margarine and other solid fat formulations.MethodsThirty human volunteers were fed complete, whole food diets during 4 wk periods, where total fat (~31% daily energy, >70% from the test fats) and fatty acid composition were tightly controlled. A crossover design was used with 3 randomly-assigned diet rotations and repeated-measures analysis. One test fat rotation was based on palm olein (POL) and provided 12.0 percent of energy (%en) as palmitic acid (16:0); a second contained trans-rich partially hydrogenated soybean oil (PHSO) and provided 3.2 %en as trans fatty acids plus 6.5 %en as 16:0, while the third used an interesterified fat (IE) and provided 12.5 %en as stearic acid (18:0). After 4 wk the plasma lipoproteins, fatty acid profile, as well as fasting glucose and insulin were assessed. In addition, after 2 wk into each period an 8 h postprandial challenge was initiated in a subset of 19 subjects who consumed a meal containing 53 g of test fat.ResultsAfter 4 wk, both PHSO and IE fats significantly elevated both the LDL/HDL ratio and fasting blood glucose, the latter almost 20% in the IE group relative to POL. Fasting 4 wk insulin was 10% lower after PHSO (p > 0.05) and 22% lower after IE (p < 0.001) compared to POL. For the postprandial study the glucose incremental area under the curve (IAUC) following the IE meal was 40% greater than after either other meal (p < 0.001), and was linked to relatively depressed insulin and C-peptide (p < 0.05).ConclusionBoth PHSO and IE fats altered the metabolism of lipoproteins and glucose relative to an unmodified saturated fat when fed to humans under identical circumstances.

Letter to the editor: healthy alternatives to trans fats

Consumption of trans fats is associated with an increase of cardiovascular disease (CVD) risk. To comply with regulatory policies and public health authorities recommendations, trans fats should be replaced in food products. The study by Sundram et al. (Nutrition & Metabolism 2007, 4:3) reporting the effect on CVD risk factors of interesterified fat (IE) and partially hydrogenated soybean oil (PHSO) compared to palm olein (POL) has been critically analyzed. The study design and in particular the composition of the tested fats was not suitable to properly answer the question raised regarding the effect of alternative ingredients to trans fats on plasma lipids. The observed effects are divergent with predicted data derived from the literature model consolidated using the individual results of 60 randomized clinical trials. The results of the study published by Sundram and co-workers have to be considered with awareness.

Iron accumulation in oil during the deep‐fat frying of meat

AbstractIron accumulation in oil is a potential problem when frying food containing substantial amounts of iron. Selected meat products (skinless chicken breast, beef liver, and lean beef) were ground and fried (ca. 2‐cm spheres, ca. 10 g/sphere) in partially hydrogenated soybean oil (PHSBO). Samples (450 g) of ground meat were fried 3 times/h for 8 h/d for 3 d. Oil samples were collected for analysis for iron (every 8 h) and oil degradation (every 4 h) and replaced with fresh oil. The iron contents of oil samples after 3 d of frying were approximately 0.11, 0.48, and 4.01 mg of iron/kg of PHSBO for the oil used to fry chicken, beef, and liver, respectively. There was a notable darkening in color and an increased tendency to foam for the beef liver oil sample compared with the other samples. After frying, the acid values were 0.9, 1.1, and 1.4 for the oil samples for chicken, beef, and liver, respectively. After frying, the p‐anisidine values were 11.5, 12.8, and 32.6 for the oil samples for chicken, beef, and liver, respectively; the food oil sensor values were 0.96, 0.96, and 0.83 for the oil samples for chicken, beef, and liver, respectively.

Vegetable Oil Stability at Elevated Temperatures in the Presence of Ferric Stearate and Ferrous Octanoate

The thermoxidative stability of partially hydrogenated soybean oil (PHSBO) was examined after addition of ferric stearate and ferrous octanoate, and then heating the samples at 120, 160, 180, and 200 degrees C. In a second experiment, the effect of iron concentration (ferric stearate) on PHSBO stability was examined at 180 degrees C, and at concentrations of approximately 0.5 and 1.2 mg of added iron/kg PHSBO. Oil samples were heated continuously for 72 h and sampled every 12 h. The acid value, p-anisidine value, color, dielectric constant and the triacylglycerol polymer content of oil samples were compared to oil samples containing no added iron. Generally, the value of each oxidative index increased with (1) an increase in temperature, (2) an increase in heating time, and/or (3) an increase in iron. The results demonstrate that low concentrations of iron will substantially increase the rate of oxidation for vegetable oil samples heated to temperatures of 120 degrees C to 200 degrees C.

Frying oil and fat quality measured by chemical, physical, and test kit analyses

AbstractThe performance of soybean oil (SBO) and a partially hydrogenated soybean oil (PHSBO) was monitored by chemical, physical, and test kit analyses during 50 h of deep‐frying of potatoes in SBO and 50 h of deep‐frying of potatoes in PHSBO. The oxidative stability of SBO and PHSBO was measured by the iodine value, color index, FFA content, total polar compounds, and FA analysis of deep‐frying SBO and PHSBO. SBO, with higher levels of unsaturated FA, had the faster rate of formation of geometric and positional isomers of unsaturated FA as measured by GC with standards. PHSBO performance under deep‐frying conditions was significantly better than SBO with respect to iodine value, color index, and total polar compounds. The results from analyses using test kits had a good correlation with analytical parameters.

Nutritional Evaluation of an Inter-Esterified Perilla Oil and Lard in Comparison with Butter and Margarine Based on the Survival of Stroke-Prone Spontaneously Hypertensive (SHRSP) Rats

Some kinds of vegetable oil and a partially-hydrogenated oil shorten the survival of the stroke-prone spontaneously hypertensive (SHRSP) rats compared with perilla seed oil, soybean oil and lard. The n-3/n-6 ratio of constituent fatty acids, phytosterol content and other factors in these oils have been proposed to affect the survival of this strain. Here, we examined the safety of a fat produced by the inter-esterification of perilla oil and lard (Perilla-Lard) on the bases of the survival of SHRSP rats. The mean survival time decreased in the order of the butter, the Perilla-Lard, the lard, the margarine and the partially-hydrogenated soybean oil (Hyd.Soy) group. The correlations between survival time and cholesterol content or phytosterol content in the diet were analyzed, and the probable health benefits of the new margarine-type fats made of animal fats and oils with high n-3/n-6 ratios were discussed.

Determination of nonvolatile components in polar fractions of rice bran oils

AbstractHigh‐oryzanol rice brain oil (HORBO), rice bran oil (RBO), and partially hydrogenated soybean oil (PHSBO) were used to prepare french fries. Polar fractions of the three oils were analyzed for nonvolatile components by high‐performance size‐exclusion chromatography (HPSEC) with ELSD. In all frying experiments, both HORBO and RBO yielded predominantly dimeric and monomeric materials. The concentrations of polymeric species in HORBO and RBO were greater than in PHSBO. The major degradation products from HORBO, RBO, and PHSBO were dimers (8.93 mg/100 mg oil), monomers (10.5 mg/100 mg oil), and DG (22.4 mg/100 mg oil), respectively. Thermal degradation via hydrolysis was much greater in PHSBO than in HORBO or RBO. Distribution data indicated that the extent of polymer formation from frying was in the order RBO&gt;HORBO &gt;PHSBO, consistent with the degree of lipid unsaturation and the oryzanol content in these oils. HPSEC‐ELSD results from the two RBO showed that the amounts of various polymeric species, including trimers and higher polymers, were lower in HORBO than in RBO. The percentage of polar materials and the percentage of polymerized TG, which were used as indicators of oil quality and stability, decreased with increasing tocopherol and oryzanol contents in the order PHSBO&gt;HORBO&gt;RBO.

Comparison of a low‐linolenic and a partially hydrogenated soybean oil using pan‐fried hash browns

AbstractHash browns (HB) were fried (Teflon‐coated pan, ∼180°C) with low‐linolenic acid (LL‐SBO) and creamy partially hydrogenated soybean oils (PH‐SBO). High‐performance size‐exclusion chromatography of the oil extracted before heating indicated a relatively low polymer content (LL‐SBO, 3.8%; PH‐SBO, 1.6%), although the oil remaining in the pan after frying had a much greater polymer content (38.8%, LL‐SBO; 17.5%, PH‐SBO). The percentage of altered TAG in the LL‐SBO sample (extracted from HB) was 34.4% after frying, whereas the PH‐SBO had 33.2% altered TAG (as determined by supercritical fluid chromatography). In the LL‐SBO pan‐fried HB samples (not the extracted oil), 2‐pentanone, hexanal, 2‐hexenal, trans‐2‐heptenal, 2‐pentylfuran, and trans‐2‐octenal were found, whereas the major volatile compounds in the HB fried with PH‐SBO included hexanal, trans‐2‐hexenal, and trans‐2‐heptenal. Hexanal was the most abundant volatile compound in both HB samples (LL‐SBO, 2.7 ppm; PH‐SBO, 0.3 ppm). There were significant differences in the polymer content, hexanal content, p‐anisidine values, and Foodoil sensor readings between LL‐SBO and PH‐SBO (P&lt;0.05). The PH‐SBO sample was more stable than the LL‐SBO sample. Moreover, the LL‐SBO oil sample in the pan after frying had the greater increase in polymer content.