Stabilization of Camelina Oil with Synthetic and Natural Antioxidants

Camelina oil was found to have a much lower Oil Stability Index and higher p-anisidine rates in the oven storage test than either rapeseed or sunflower oils. Stabilization of camelina oil was evaluated with 21 food grade synthetic and natural antioxidants and antioxidant formulations, using both the Oil Stability Index (OSI) and the oven storage test. The Oil Stability Index of camelina oil was able to be increased above that of rapeseed oil with TBHQ and its formulation with citric acid, and above that of sunflower oil with EGC, EGCG, carnosic acid, propyl gallate, rosemary extract with ascorbyl palmitate or with gallic acid. para-Hydroxyphenols were found to be more effective than ortho-hydroxyphenols and monohydroxyphenols had no significant effect on the OSI. Good correlation (R ² = 0.96) was found between the stabilizing effect of ortho-hydroxyphenols and the molarity of the phenyl hydroxyl groups per weight of antioxidant. The oven storage test carried out with six of the evaluated antioxidants indicated that p-anisidine rates of camelina oil stabilized with commercial formulations of TBHQ with citric acid or rosemary extract with ascorbyl palmitate were about the same as that of sunflower oil, an almost 90% rate reduction when compared to camelina oil. Accordingly, camelina oils stabilized with TBHQ/citric acid and rosemary extract/ascorbyl palmitate formulations were more stable than rapeseed and sunflower oils, respectively in terms of OSI induction times and p-anisidine rates.     

Antioxidant Activity of Phytochemicals from Distillers Dried Grain Oil

A distillate was obtained by molecular distillation of oil extracted from distillers dried grains (DDG). The distillers dried grain oil distillate (DDGD) contained phytosterols, steryl ferulates, tocopherols, tocotrienols, and carotenoids. DDGD was tested for its impact on the oxidative stability index (OSI) at 110 °C of soybean, sunflower, and high-oleic sunflower oils, as well as the same oils that were stripped of their natural tocopherols and phytosterols. In addition, the impact of added DDGD on the stability of stripped sunflower oil during an accelerated storage study conducted at 60 °C was also determined. DDGD (0.5–1% w/w) had little impact on the OSI of soybean, sunflower, and high-oleic sunflower oil, but at levels of 0.1–1% it significantly increased the OSI for stripped soybean, sunflower, and high-oleic sunflower oil in a dose-dependent manner. DDGD also delayed peroxide value, conjugated diene, and hexanal formation during accelerated storage of stripped sunflower oil. The antioxidant activity is probably due to the combination of tocopherols, tocotrienols, and steryl ferulates.     

A rapid method for analysis of tert-butyl hydroquinone (TBHQ) in ethyl esters of fish oil

A rapid, quantitative gas Chromatographic method is described for quantitating the phenolic antioxidant,tert- butyl hydroquinone (TBHQ), in fish oil ethyl esters. The procedure entails silyl derivatization of TBHQ in an acetonitrile solution of ethyl esters followed by capillary gas chromatography (GC) analysis with an internal standard method of quantitation. Average recoveries of spiked samples were 98% at the legal limit of .02% (200 μg/g). The method can accurately determine as little as 20 μ/g of TBHQ in ethyl esters of fish oil. The technique has been applied to ethyl esters of vegetable oils with equal success.     

Antioxidant activity of almonds and their by-products in food model systems

Antioxidant activities of almond whole seed, brown skin, and green shell cover extracts, at 100 and 200 ppm quercetin equivalents, were evaluated using a cooked comminuted pork model, a β-carotene-linoleate model, and a bulk stripped corn oil system. Retention of β-carotene in a β-carotene-linoleate model system by almond whole seed, brown skin, and green shell cover extracts was 84–96, 74–83, and 71–93%, respectively. In a bulk stripped corn oil system, green shell cover extract performed better than brown skin and whole seed extracts in inhibiting the formation of both primary and secondary oxidation products. In a cooked comminuted pork model system, green shell cover and brown skin extracts inhibited the formation of TBARS, total volatiles, and hexanal more effectively than did the whole seed extract. HPLC analysis revealed the presence of caffeic, ferulic, p-coumaric, and sinapic acids as the major phenolic acids in all three almond extracts examined.     

Temperature Dependence of HNE Formation in Vegetable Oils and Butter Oil

The temperature dependence of the formation of toxic 4-hydroxy-2-trans-nonenal (HNE) was investigated in high and low linoleic acid (LA) containing oils such as corn, soybean and butter oils. These oils contain about 60, 54 and 3–4% of LA for corn, soybean and butter oils, respectively. The oils were heated for 0, 0.5, 1, 2, and 3 h at 190 °C and for 0, 5, 15 and 30 min at 218 °C. HNE concentrations in the oils were analyzed by high performance liquid chromatography (HPLC). The maximum HNE concentrations in heated (190 °C) corn, soybean and butter oils were 5.46, 3.73 and 1.85 μg HNE/g oil, respectively. The concentration of HNE at 218 °C increased continuously for all the three oils, although they were heated for much shorter periods compared to the lower temperature of heating (190 °C). HNE concentration at 30 min reached the maximum of 15.48, 10.72 and 6.71 μg HNE/g oil for corn, soybean and butter oils, respectively. HNE concentration at higher temperature (218 °C) was 4.9, 3.7, and 8.7 times higher than at the lower temperature (190 °C) and 30 min of heating for corn, soybean and butter oils, respectively. It was found that HNE formation was temperature dependant in the tested oils.     

The effect of 12, oxo-cis, 9-octadecenoic acid on the autoxidation of stripped corn oil

The effect of 12, oxo-cis, 9-octadecenoic acid (keto acid) on the autoxidation of stripped corn oil at 37°C. has been studied. The stripped corn oil containing 50 μg. of tocopherol per g. was prepared by Distillation Products Industries by removal of approximately 10% of the corn oil in a molecular still. Addition of 2.5% of the keto acid resulted in a higher rate of oxidation. As the concentration of keto acid was increased from 0 to 10%, peroxides increased rapidly, resulting in a shorter induction period. The antioxidants BHA, BHT, propyl gallate, NDGA, Ethoxyquin, and DPPD were found to lengthen the induction period for stripped corn oil in the presence of keto acid. DPPD was found to be by far the most effective and α-tocopherol acetate had no antioxidant activity in presence of keto acid. It was observed that keto acid oxidized very rapidly with the formation of peroxides and probable breakdown to free radicals. These free radicals then accelerated the autoxidation of stripped corn oil through a chain reaction mechanism. Heptanoic, suberic, and azelaic acids were identified among the breakdown products of keto acid. This investigation was supported by research grant No. A-1671 from the National Institute of Health, U. S. Public Health Service.     

Do antioxidants improve the oxidative stability of oil-in-water emulsions?

Oil-in-water emulsions were prepared with 30% stripped sunflower oil, stabilized by 20 g/L BSA and homogenized under high pressure to obtain a mean droplet size near 0.5 μm. The emulsions were shown to be physically stable during storage in a shaker at 47°C for 5 d. Such a medium was suitable to test the efficiency of different types of antioxidants. Oxidation of control emulsions appeared rapidly without a lag phase, and the contents of conjugated dienes and hexanal reached a plateau after around 20 h. In the presence of EDTA, the oxidation was strongly inhibited, suggesting that some metallic ions present in the oil or the protein solution act as inducers. Ascorbic acid and ascorbyl palmitate were inactive. Isoeugenol was found to be a powerful antioxidant, better than eugenol, α-tocopherol, and Trolox.     

Antioxidant Activity Evaluation of Tocored through Chemical Assays,Evaluation in Stripped Corn Oil,and CAA Assay

γ‐Tocopherol‐5,6‐quinone (tocored) is a crucial oxidized product of γ‐tocopherol (γ‐T) found in edible oil. Previously published studies on antioxidant activity (AOA) of tocored are not consistent. This study aims to monitor its AOA comprehensively through chemical assays (1,1‐diphenyl‐2‐picrylhydrazyl [DPPH] and ferric reducing antioxidant power [FRAP]), antioxidant evaluation in a food model system (stripped corn oil), and cellular antioxidant activity (CAA) assay, which would reasonably widen the knowledge of the AOA of γ‐T and tocored. In both DPPH and FRAP assays, tocored shows less AOA than γ‐T. Results of chemical properties in the Schaal oven test show that tocored possesses better AOA than γ‐T. Correlation coefficients of γ‐T and tocored between peroxide and K₂₃₄ or p‐AnV are 0.8784–0.9875 and 0.8716–0.9879, respectively. The CAA assay also shows that tocored possesses better cellar AOA than γ‐T, with an EC₅₀ at 21.55 µg mL^?1. Drawing conclusions from the results from chemical assays, evaluation in stripped corn oil, and CAA assay, tocored is verified as a potent antioxidant in edible vegetable oils compared to γ‐T. Practical Applications: The present work widens the knowledge of antioxidant activity of tocored and gamma‐tocopherol, and contributes to the understanding of existing antioxidant activity when gamma tocopherol is depleted when edible oils are in storage and processing processes.     

Hydroperoxide as a Prooxidant in the Oxidative Stability of Soybean Oil

Fifteen milliliters of soybean oil having peroxide value (PV) of 0, 2, 4, 6, 8, or 10 meq/kg oil in a 35 mL serum bottle was sealed air-tight with a Teflon rubber septum and aluminum cap and was stored in a forced-air oven at 50 °C. The oxidative stability of soybean oil was evaluated daily for six days by measuring the headspace oxygen content and volatile compounds in the headspace of a sample bottle by gas chromatography. As the initial PV of the oil increased from 0 to 2, 4, 6, 8 and 10, the headspace oxygen decreased and the volatile compounds increased at p < 0.05. Hydroperoxide accelerated the oxidation of soybean oil. The correlation coefficient (R ²) between the headspace oxygen and the volatile compounds was 0.95. The increase of tertiary butyl hydroquinone (TBHQ) from 0 to 50 ppm for the oil of PV 4 or 8 had a significant effect on the oxidative stability at p < 0.05. The increase from 50 to 100 ppm for the oil of PV 4 or 8 did not significantly increase the stability at p > 0.05. The oxidative stability of PV 8 meq/kg and 50 ppm TBHQ was better than the control with PV 0 and 0 ppm TBHQ at p < 0.05. TBHQ was an effective antioxidant to improve the oxidative stability of soybean oil.     

Antioxidant activity of amino acids bound to trolox-C

Various amino acids, selected for their potential antioxidant activity, were, covalently attached to 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox-C), a lower homolog of vitamin E that has great antioxidant effectiveness. The resulting Troloxylamino acids (T-AA) had greater antioxidant effectiveness than Trolox-C in a linoleate emulsion system oxidized by hemoglobin. Troloxyl-tryptophan-methyl ester and Troloxyl-methionine-methyl ester were the most effective T-AA evaluated in the linoleate emulsion. However, butylated hydroxyanisole (BHA), butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and α-tocopherol were more antioxidant than any T-AA in the emulsion system. In a Schaal oven test at 45 C. Trolox-C was by by far the most effective antioxidant evaluated in corn oil. BHT and Troloxylcysteine had significant antioxidant activity in corn oil, but no other T-AA was antioxidant in corn oil. In butter oil, Trolox-C again had the highest antioxidant activity, and BHA and BHT were also highly antioxidant. All t-AA had antioxidant activity in butter oil, with Troloxyl-methioninc and Troloxyl-cysteine having the grcatest antioxidant effectiveness. The T-AA of highest antioxidant activity were hydrolyzed by chymotrypsin and/or trypsin, in vitro.     

Fatty Acid Composition,Oxidative Stability,and Radical Scavenging Activity of Vegetable Oil Blends with Coconut Oil

Coconut (Cocos nucifera) contains 55–65% oil, having C12:0 as the major fatty acid. Coconut oil has >90% saturates and is deficient in monounsaturates (6%), polyunsaturates (1%), and total tocopherols (29 mg/kg). However, coconut oil contains medium chain fatty acids (58%), which are easily absorbed into the body. Therefore, blends of coconut oil (20–80% incorporation of coconut oil) with other vegetable oils (i.e. palm, rice bran, sesame, mustard, sunflower, groundnut, safflower, and soybean) were prepared. Consequently, seven blends prepared for coconut oil consumers contained improved amounts of monounsaturates (8–36%, p < 0.03), polyunsaturates (4–35%, p < 0.03), total tocopherols (111–582 mg/kg, p < 0.02), and 5–33% (p < 0.02) of DPPH (2,2-diphenyl-1-picrylhydrazyl free radicals) scavenging activity. In addition, seven blends prepared for non-coconut oil consumers contained 11–13% of medium chain fatty acids. Coconut oil + sunflower oil and coconut oil + rice bran oil blends also exhibited 36.7–89.7% (p < 0.0005) and 66.4–80.5% (p < 0.0313) reductions in peroxide formation in comparison to the individual sunflower oil and rice bran oil, respectively. It was concluded that blending coconut oil with other vegetable oils provides medium chain fatty acids and oxidative stability to the blends, while coconut oil will be enriched with polyunsaturates, monounsaturates, natural antioxidants, and a greater radical scavenging activity.     

Effects of Curcumin on the Oxidative Stability of Oils Depending on Type of Matrix,Photosensitizers, and Temperature

The photosensitizing activity of curcumin was tested in corn oil and oil‐in‐water (O/W) emulsion systems under visible light irradiation. In addition, the antioxidative/prooxidative properties of curcumin were evaluated in corn oil at 100 °C and in O/W emulsion at room temperature under riboflavin photosensitization or at 60 °C in the dark. Curcumin acted as a photosensitizer in corn oil and O/W emulsions . The oxidative stability of corn oil samples containing curcumin (0–5.0 mmol/kg oil) were not significantly different (p > 0.05) at 100 °C, implying curcumin did not act as an antioxidant nor a prooxidant in corn oil. However, curcumin inhibited lipid oxidation in O/W emulsions under riboflavin photosensitization at room temperature and 60 °C in the dark. The photosensitization and antioxidant abilities of curcumin were greatly influenced by matrix types and presence of riboflavin. Therefore, antioxidative or prooxidative characteristics of curcumin should be evaluated considering matrix type including bulk oil or O/W emulsions and presence of visible light irradiation.     

Surfactant-Based Oil Extraction of Corn Germ

An aqueous surfactant-based extraction system was developed for the extraction of corn oil from corn germ with anionic extended surfactants. The surfactants used in this study were sodium linear-alkyl polypropoxylated polyethoxylated sulfates (C_12,14–P₁₀–E₂–SO₄Na and C₁₀–P₁₈–E₂–SO₄Na). Interfacial tension, critical microemulsion concentration (CμC), and optimum salinity values of the extended surfactants with corn oil were determined. In the extraction process, the ground corn germ was shaken with predetermined surfactant and salt concentrations at room temperature for 45 min. About 83%, the sum of total free oil and total oil-in-water emulsion, of the corn oil was extracted from the corn germ using a formulation of 0.4% C_12,14–P₁₀–E₂–SO₄Na and 1% NaCl. A solid/liquid ratio of 1/10 performed best for efficient oil recovery. The chemical compositions of the extracted corn oils were found to be similar to that of hexane extracted corn oil.     

Effect of natural antioxidants in virgin olive oil on oxidative stability of refined,bleached, and deodorized olive oil

The factors influencing the oxidative stability of different commercial olive oils were evaluated. Comparisons were made of (i) the oxidative stability of commercial olive oils with that of a refined, bleached, and deodorized (RBD) olive oil, and (ii) the antioxidant activity of a mixture of phenolic compounds extracted from virgin olive oil with that of pure compounds andα-tocopherol added to RBD olive oil. The progress of oxidation at 60°C was followed by measuring both the formation (peroxide value, PV) and the decomposition (hexanal and volatiles) of hydroperoxides. The trends in antioxidant activity were different according to whether PV or hexanal were measured. Although the virgin olive oils contained higher levels of phenolic compounds than did the refined and RBD oils, their oxidative stability was significantly decreased by their high initial PV. Phenolic compounds extracted from virgin olive oils increased the oxidative stability of RBD olive oil. On the basis of PV, the phenol extract had the best antioxidant activity at 50 ppm, as gallic acid equivalents, but on the basis of hexanal formation, better antioxidant activity was observed at 100 and 200 ppm.α-Tocopherol behaved as a prooxidant at high concentrations (>250 ppm) on the basis of PV, but was more effective than the other antioxidants in inhibiting hexanal formation in RBD olive oil.o-Diphenols (caffeic acid) and, to a lesser extent, substitutedo-diphenols (ferulic and vanillic acids), showed better antioxidant activity than monophenols (p- ando-coumaric), based on both PV and hexanal formation. This study emphasizes the need to measure at least two oxidation parameters to better evaluate antioxidants and the oxidative stability of olive oils. The antioxidant effectiveness of phenolic compounds in virgin olive oils can be significantly diminished in oils if their initial PV are too high.     

Antioxidant Activity of Oat Malt Extracts in Accelerated Corn Oil Oxidation

Oat cultivar AC Vermont was malted to concentrate antioxidants, milled to fractionate only the endosperm portion and extracted with methanol to isolate the crude antioxidants. The oat malt antioxidant fraction was assessed as a natural antioxidant based upon enhancing the stability of corn oil against oxidation and compared to the synthetic antioxidant butylated hydroxytoluene (BHT). The induction time (time required for the formation of 10 meq hydroperoxide per kilogram corn oil thermally oxidized) was used to measure antioxidant activity of oat antioxidant or BHT. The protection factor achieved by crude oat malt antioxidant extract concentrate at 0.26% (2,600 μg/g) was comparable to BHT (75 μg/g). The antioxidant activity of the oat and barley malt extract concentrates was not significantly different. However, the extract concentrate of oat malt had 44% less color compared to that of barley malt at equal concentrations showing its potential as a natural food antioxidant.     

A Comparison of the Levels of Lutein and Zeaxanthin in Corn Germ Oil,Corn Fiber Oil and Corn Kernel Oil

All commercial corn oil is obtained by pressing corn germ and/or extracting the germ with hexane. In the current study, six types of corn oil were prepared by extracting corn germ, corn fiber and ground corn, each with hexane or with ethanol. The levels of lutein, zeaxanthin and other carotenoids were quantitatively analyzed in the six corn oils. The levels of lutein + zeaxanthin in the oil ranged from 2.3 μg/g for hexane-extracted corn germ oil to 220.9 μg/g for ethanol-extracted ground corn oil. These results indicate that a diet that includes 30 g (~2 tbsp) per day of the unrefined corn oil obtained by extracting ground corn with ethanol would provide ~6 mg of lutein + zeaxanthin, the daily dosage that is currently considered to be necessary to slow the progression of age-related macular degeneration. Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.     

Addition of ferulic acid,ethyl ferulate,and feruloylated monoacyl- and diacylglycerols to salad oils and frying oils

To determine antioxidative effects of ferulic acid and esterified ferulic acids, these compounds were added to soybean oils (SBO), which were evaluated for oxidative stability and frying stability. Additives included feruloylated MAG and DAG (FMG/FDG), ferulic acid, ethyl ferulate, and TBHQ. After frying tests with potato chips, oils were analyzed for retention of additives and polar compounds. Chips were evaluated for hexanal and rancid odor. After 15 h frying, 71% of FMG/FDG was retained, whereas 55% of ethyl ferulate was retained. TBHQ and ferulic acid levels were 6% and <1%, respectively. Frying oils with ethyl ferulate or TBHQ produced significantly less polar compounds than SBO with no additives. Chips fried in SBO with TBHQ or ferulic acid had significantly lower amounts of hexanal and significantly less rancid odor after 8 d at 60°C than other samples. Oils were also aged at 60°C, and stability was analyzed by PV, hexanal, and rancid odor. Oils with TBHQ or FMG/FDG had significantly less peroxides and hexanal, and a lower rancid odor intensity than the control. FMG/FDG inhibited deterioration at 60°C, whereas ethyl ferulate inhibited the formation of polar compounds in frying oil. Ferulic acid acted as an antioxidant in aged fried food. TBHQ inhibited oil degradation at both temperatures. Presented at the 94th AOCS Meeting & Expo, Kansas City, MO, May 4–7, 2003.     

High‐Purity Tocored Improves the Stability of Stripped Corn Oil Under Accelerated Conditions

γ‐Tocopherol‐5,6‐quinone (tocored) is of importance among the γ‐tocopherol (γ‐T) oxidant products and found in corn germ oil. Investigation on tocored is impeded in part by the difficulty to access high purity tocored. In this present study, high‐purity tocored is successfully prepared, and its antioxidant activity, together with γ‐T and TBHQ (positive control) in increasing concentrations in stripped corn germ oil is evaluated by Rancimat and Schaal oven tests. The stabilization factor in the Rancimat tests increases significantly (p < 0.05) along with an increase in the levels of antioxidants. Furthermore, tocored exhibits higher stabilization than γ‐T in the Schaal oven tests, although its efficacy gradually increases up to 100 mg kg^–1 and decreases significantly at higher levels (from 100 to 500 mg kg^–1), drawn from the comprehensive parameter A (considering both efficiency and strength) changes (5.06–11.21). In addition, the curves illustrating the residual contents of tocored and γ‐T run in different ways when the four levels are taken into consideration, further bearing the above results. Tocored tends to be a potent natural antioxidant for edible corn germ oil preservation. Practical Application: The present work provides more clear procedures for high‐purity tocored synthesis. Furthermore, tocored may be a potential natural antioxidant that is especially suitable for lipid base food substrates. The results of the present work contribute to the deeper understanding of the antioxidant activity of γ‐tocopherol. The antioxidant activity of tocored is higher than γ‐tocopherol in Schaal oven test. Tocored is a bright orange‐red substance that affects the appearance of the edible oil. Meanwhile, γ‐tocopherol is well known for its valuable health benefits, and appropriate measures should be adopted to store oils (corn oil, soybean oil, and so on) rich in γ‐tocopherol to control transformation in order to keep stability optimal. To some degree, the practical applications of the present results are also related to the processing and storage of edible oils.     

Antioxidant Activity of Rambutan (Nephelium lappaceum L.) Peel Extract in Soybean Oil during Storage and Deep Frying

Rambutan (Nephelium lappaceum L.) peel (RBP) is discarded as the main by‐product during processing of the fruit. Increasing attention is now paid to the valorization of RBP for the recovery of valuable compounds. Geraniin, ellagic acid, quercetin, and rutin are the main phenolic compounds found in methanolic RBP extract. Extracted rambutan peel powder (ERPP) is used to evaluate the oxidative stability of soybean oil stored at 4 and 30 °C in the dark and light and deep fried with potatoes at 160 °C. Tert‐butylhydroquinone (100 µg g^?1 oil, TBHQ) serves as positive control. Oil supplemented with ERPP of 1000 µg gallic acid equivalents (GAE) g^?1 of oil shows positive effects on the retardation of the oxidation process during storage in comparison with oil without addition. During deep frying, either ERPP (1000 µg GAE g^?1) or TBHQ retards the lipid oxidation of oil. Levels of thiobarbituric acid reactive substances of potatoes fried in oil fortified with the extract and TBHQ (0.4–0.59 µg g^?1) are much lower than those without the extract (1.31 ± 0.10 µg g^?1) (p < 0.05). Therefore, RBP extract exhibits favorable antioxidant effects and can be used for effectively inhibiting lipid oxidation in oil during storage and deep frying. Practical Applications: An extract from rambutan fruit peel containing phenolic compounds, that is, geraniin, ellagic acid, rutin, and quercetin showed promising results to be used as potential antioxidants in soybean oil during deep frying. Both oxidation of the frying oil as well as the oxidation of the food product, that is, potatoes were inhibited. These results demonstrated that rambutan fruit peel extract can be used as a natural antioxidant in frying oil to replace synthetic antioxidants, that is, TBHQ.     

Retardation of rancidity in deep-fried instant noodles (ramyon)

The storage stability of instant fried noodles (ramyon) was determined by accelerated aging at 63 C with organoleptic evaluation of the onset of rancidity. Three methods of extending the shelf-life of ramyon were examined: (a) addition of 200 ppm antioxidant, butylated hydroxyanisole (BHA), t-butylhydroquinone (TBHQ), or a polymeric antioxidant (Poly-A) to the frying (palm) oil; (b) coating the inner surface of the polyethylene package with TBHQ equivalent to 200, 500 and 1000 ppm based on the oil in the ramyon; and (c) addition of a mixture of 200 ppm TBHQ and 200 or 500 ppm disodium ethylene-diaminetetraacetate (EDTA) to the frying oil. When the antioxidants were added to the oil, BHA and Poly-A approximately doubled while TBHQ tripled the shelf-life of ramyon. The mixture of TBHQ (200 ppm) and disodium EDTA (500 ppm) in the frying oil quintupled the shelf-life. The inner surface application of TBHQ (200 ppm) extended shelf-life twice that of an equal amount of TBHQ in the frying oil. Rancid off-flavors developed slowest in noodles with a _w 0.3. Hexanal concentration in ramyon was a good indicator of the development of oxidative rancidity. Organoleptic evaluation showed the flavor of ramyon was objectionable when hexanal concentration reached 3.5 ppm based on the weight of ramyon (as is). The relative effectiveness of antioxidants in preventing off-flavor in ramyon could be determined from the hexanal concentration in stored ramyon. This paper was presented at the AOCS meeting in Philadelphia, Pennsylvania, in May 1985. It is contribution #85-167-J, cooperative investigation among the Agricultural Research Service, U.S. Department of Agriculture, and the departments of Grain Science and Industry and Agricultural Engineering, Kansas Agricultural Experiment Station, Kansas State University.