Journal of the American Oil Chemists' Society (v.88, #5)

Flaxseed oil (FO) containing crawfish (Procambarus clarkii) astaxanthin (FOA) was evaluated for lipid oxidation and astaxanthin degradation. The FOA was analyzed for astaxanthin content, free fatty acids (FFA), peroxide value (PV), fatty acid methyl esters (FAMEs) profile, and color. The amount of extractable astaxanthin in the crawfish byproducts was 3.02 mg/100 g of crawfish byproducts. FOA and FO had a similar alpha-linolenic acid (ALA) content (on a weight% basis). The FO was lighter and more yellow in color than FOA. The oxidation rate of FOA was lower than that of FO. When FO and FOA were heated to 30 °C, both oils exhibited minimal lipid oxidation with increasing heating time, whereas FO, when heated to 40, 50, 60 °C, had a higher lipid oxidation rate than FOA with increasing the heating time from 0 to 4 h. Astaxanthin was an effective antioxidant agent in FO when it was heated from 30 to 60 °C. The degradation of astaxanthin in FOA could be described by first order reaction kinetics. Astaxanthin was stable in flaxseed oil at 30 and 40 °C, while its stability decreased significantly at 50 and 60 °C. The rate of astaxanthin degradation in FOA was significantly influenced by temperature.
Keywords: Crawfish; Flaxseed oil; Astaxanthin degradation; Lipid oxidation rate

Effect of Stripping Methods on the Oxidative Stability of Three Unconventional Oils by Abdalbasit Mariod; Bertrand Matthäus; Ismail H. Hussein (603-609).
Stripped and non-stripped oils from Sclerocarya birrea [marula oil (SCO)], Aspongopus viduatus [melon bug oil (MBO)] and Agonoscelis pubescens [sorghum bug oil (SBO)], traditionally used for nutritional applications in Sudan, were investigated for their fatty acid and tocopherol composition, and their oxidative stability. Three stripping methods were used, phenolic compounds extraction, silicic acid column, and aluminum oxide column. The stripping methods did not affect the fatty acid composition. Non-stripped SCO, MBO and SBO contained oleic, palmitic, stearic and linoleic acids, which were not significantly (P < 0.05) different than stripped SCO, MBO and SBO. The stripping methods’ effect on the tocopherol composition of the studied oils, the total amount of tocopherol in non-stripped oils decreased by extraction of phenolic compounds, mean that part of the tocopherols was extracted with the phenolic compounds. No traces of tocopherols were found in oils stripped using silicic and aluminum columns and the tocopherols were eliminated during the stripping processes. The stability of SCO, MBO and SBO oils was 43, 38 and 5.1 h, respectively, this stability decreased by 22.0, 37.6 and 23.5%, respectively after extraction of phenolic compounds. This stability decreased by 96.9, 98.2 and 90.2% respectively, when stripped using the aluminium column and decreased by 92.6, 96.1 and 86.3% when stripped by the silicic column. It is possible to assume that the tocopherols and phenolic compounds play a more active role in the oxidative stability of the oils than the fatty acid composition and phytosterols.
Keywords: Agonoscelis pubescens ; Aspongopus viduatus ; Aluminum oxide column; Oxidative stability; Stripping; Silicic column; Sclerocarya birrea

Oxidative Stability of Lipids by Means of EPR Spectroscopy and Chemiluminescence by Arkadiusz Szterk; Ireneusz Stefaniuk; Bożena Waszkiewicz-Robak; Marek Roszko (611-618).
The aim of this study was to investigate the oxidation of selected vegetable oils (CLSO, CCSO, CBO) at accelerated oxidation rates. Several seldom used analytical methods were applied including electron paramagnetic resonance (EPR), spin trapping with α-(4-pyridyl-1-oxide)-N-tert-butylnitrone (POBN) and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), Fe2+-induced chemiluminescence, Rancimat tests, and the determination of conjugated diens at λ = 233 nm. The antioxidative properties of POBN and DMPO were also investigated. The time required for each method was determined. EPR spectrometry of trapped radicals generated during oxidation turned out to be the fastest method to determine oxidative stability. Chemiluminometric determination of oxidation kinetics showed that POBN has a very strong anti-oxidative potential: it significantly (by 160–277%) lengthened the time to the chemiluminescence peak, as well as the induction time in the Rancimat test (by 110–140%). Photo-oxidation studies showed that superoxide anion radicals are the main factor responsible for the oxidation of lipids in the investigated oils.
Keywords: EPR; Chemiluminescence; Antioxidants; Vegetable oils

Optimization of Biomass and Arachidonic Acid Production by Aureispira maritima Using Response Surface Methodology by Sutanate Saelao; Akkharawit Kanjana-Opas; Songsri Kaewsuwan (619-629).
Statistically based experimental designs, based on the Plackett–Burman protocol, were applied to the optimization of biomass and arachidonic acid (ARA) production in Aureispira maritima shake-flask cultures. Tryptone and culture temperature were identified to have a significant effect on biomass production, whereas ARA production was only affected significantly by the pH and agitation rate. These four factors were subsequently optimized using response surface methodology. The validity of the optimum conditions was verified by separate experiments in which biomass and ARA yield were increased 4.02-fold (2.05 g l−1) and 3.59-fold (21.50 mg g−1), respectively, in 3-day fermentations. Under non-optimized culture conditions the corresponding values were 0.51 g l−1 and 5.99 mg g−1, respectively. The results suggest that A. maritima might be a potential strain for further large scale investigations to determine whether this bacterium might be suitable for commercial production of ARA. To our knowledge, this is the first report of the statistically optimization of biomass and ARA production from the marine gliding bacterium A. maritima.
Keywords: Aureispira maritima ; Arachidonic acid; Plackett–Burman design; Response surface methodology; Central composite design

Effect of Grape Seed Extracts on the Physicochemical and Sensory Properties of Corn Chips during Storage by Taha M. Rababah; Sevil Yücel; Khalil I. Ereifej; Mohammad N. Alhamad; Majdi A. Al-Mahasneh; Wade Yang; Al–u’datt H. Muhammad; Khalid Ismaeal (631-637).
This study evaluated the effectiveness of grape seed extracts (GSE) on lipid oxidation of corn chips stored for 90 days in comparison to tert-butylhydroxytoluene (BHT). Proximate chemical analysis results showed that corn chips contained low moisture contents (less than 2%) and also that no significant differences were found in the dry matter values in ash, fat, protein, and fiber. Antioxidant activity of the GSE measured by an oxidative stability instrument ranged from 1.6 to 9.3 h of induction time, while BHT prevented oxidation by 18.8 h. GSE (800 ppm) increased the redness and decreased the brightness and yellowness of the corn chip samples, whereas no significant differences were observed for other concentrations of the GSE compared to the control. The peroxide values (PV) for the control and the lower concentration (200 ppm) of GSE increased from 4.5 to 32.7 mequiv/kg, and from 4.4 to18.7 mequiv/kg, respectively, while no increase in PV was found for the higher level (400 and 800 ppm) of GSE or BHT. These changes were observed after 90 days of storage. Descriptive and consumer results showed that the control and the low concentration of GSE were associated with an increase in rancidity and the appearance of off-flavor, while no noticeable increase in either rancidity or off-flavor was observed when using a higher concentration of GSE or BHT. GSE has great potential for use as a natural antioxidant to preserve the extruded corn chips.
Keywords: Lipid oxidation; Sensory; Antioxidants

Classification of Turkish Extra Virgin Olive Oils by a SAW Detector Electronic Nose by Pınar Kadiroğlu; Figen Korel; Figen Tokatlı (639-645).
An electronic nose (e-nose), in combination with chemometrics, has been used to classify the cultivar, harvest year, and geographical origin of economically important Turkish extra virgin olive oils. The aroma fingerprints of the eight different olive oil samples [Memecik (M), Erkence (E), Gemlik (G), Ayvalık (A), Domat (D), Nizip (N), Gemlik–Edremit (GE), Ayvalık–Edremit (AE)] were obtained using an e-nose consisting a surface acoustic wave detector. Data were analyzed by principal component analysis (PCA) and discriminant function analysis (DFA). Classification of cultivars using PCA revealed that A class model was correctly discriminated from N in two harvest years. The DFA classified 100 and 97% of the samples correctly according to the cultivar in the 1st and 2nd harvest years, respectively. Successful separation among the harvest years and geographical origins were obtained. Sensory analyses were performed for determining the differences in the geographical origin of the olive oils and the preferences of the panelists. The panelists could not detect the differences among olive oils from two different regions. The cultivar, harvest year, and geographical origin of extra virgin olive oils could be discriminated successfully by the e-nose.
Keywords: Extra virgin olive oil; Electronic nose; Classification; Principal component analysis; Discriminant function analysis; Sensory analysis

Effect of Bene Kernel Oil on the Frying Stability of Canola Oil by Parvin Sharayei; Reza Farhoosh; Hashem Poorazrang; Mohammad Hossein Haddad Khodaparast (647-654).
Canola oil (CAO) with (0.05–0.4%) and without added bene kernel oil (BKO) and tert-butylhydroquinone (TBHQ, 100 ppm) was used for deep-fat frying of potatoes at 180 °C for 48 h. Frying stability of the oil samples during the frying process was measured based on the variations of total polar compounds (TPC) content, conjugated diene value (CDV), acid value (AV), carbonyl value (CV) and total tocopherols (TT). In general, frying stability of the CAO significantly (P < 0.05) improved in the presence of the TBHQ and BKO. The best frying performance for the CAO was obtained by using of 100 ppm TBHQ and 0.1% BKO. The effectiveness of TBHQ and BKO at these levels was found to be nearly the same. Increasing the level of BKO from 0.1 to 0.4% caused a decrease in the oxidative stability of the CAO, indicating the pro-oxidant effect of the oils added at these levels.
Keywords: Canola oil; Frying; Bene kernel oil; TBHQ; Stability

To date, the standardized method for glycerol quantification in biodiesel production utilizes gas chromatography (GC); however, availability to manufacturers and instrumentation cost limits GC as an analytical method for general quality enforcement among producers. The method developed here is a bench top technique for quantitative determination of glycerol in biodiesel, with practical application in pharmaceutical and environmental quality control. The method extracts the glycerol contaminant from biodiesel using a normal phase solid phase extraction column (SPE). The protocol proceeds by rinsing with hexane to remove residual methyl esters, then collecting the glycerol with water. The aqueous extract is analyzed spectrophotometrically by an anthrone coloring reagent. Use of 2-g SPE columns and the solvent system developed has achieved 85% glycerol recovery. The assay applied has a detection range of 0.004–0.400% free glycerol, comparable to the established American Society of Testing and Materials (ASTM) D 6584-07 GC technique. Results were confirmed by GC and high-pressure liquid chromatography (HPLC). The bench top technique reduces the costs of operation relative to current methods, completes analysis in proficient time, requires minimal labor, and has analytical limits comparable to existing standard methods of biofuel analysis.
Keywords: Biodiesel analysis; Methyl esters; Free glycerine; Free glycerol; Anthrone; Spectrophotometric analysis

In order to improve the oxidative stability and cold flow properties of oleic acid or methyl oleate, branch chain isomerization was conducted using a beta zeolite catalyst. Reaction conditions of temperature (200–300 °C), pressure (0.1–3.0 MPa), and co-catalyst (0–2 wt%) were optimized based on branch chain conversion and the cloud point of the ester following the isomerization reaction of oleic acid or methyl oleate. Fourier transform infrared spectroscopy (FTIR) and Gas Chromatograph equipped with Mass Spectrometry (GC/MS) analyses were used to analyze and quantify the isomerization product samples, while the cloud point of each sample was tested. The lowest and therefore, best cloud point measured was −15.2 °C at conditions of 200 °C, 3 MPa, and 2% co-catalyst using methyl oleate as a starting material. The highest branch chain conversion achieved was 50% under conditions of 300 °C, 1.5 MPa and 0% co-catalyst using oleic acid as a starting material. The use of oleic acid and methyl oleate is based on whether it is optimal to carry out the skeletal isomerization before or after the esterification reaction. Performing the isomerization reaction on the ester was preferred over the fatty acid based on the trans isomerization and cloud point results. Reducing the unbranched trans isomers was desirable in obtaining a low cloud point.
Keywords: Fatty acid methyl ester; Isomerization; Branch chain; FTIR; Cloud point

A soy-based formaldehyde-free adhesive consisting of soy flour (SF), polyethylenimine (PEI), maleic anhydride (MA) and NaOH was investigated for making three-layer particleboard. The weight ratio of SF/PEI/MA/NaOH was 7/1.0/0.32/0.1. Hot-press temperature, hot-press time, particleboard density and adhesive usage were optimized in terms of enhancing the modulus of rupture (MOR), modulus of elasticity (MOE) and internal bond strength (IB) of the resulting particleboard. The MOR, MOE and IB met the minimum industrial requirements of M-2 particleboard under the following variables: hot-press temperature of 170 °C, hot-press time of 270 s, the adhesive usage of surface particles at 10 wt%, the adhesive usage of the core particles at 8 wt%, and the targeted particleboard density of 0.80 g/cm3.
Keywords: Wood adhesive; Particleboard; Soy flour; Polyethylenimine

Spectroscopic Analysis of Cotton Treated with Neutralized Maleinized Soybean Oil by Ericka N. J. Ford; Sharathkumar K. Mendon; James W. Rawlins; Shelby F. Thames (681-687).
Water-soluble vegetable oil derivatives were synthesized and investigated as biobased reagents for cellulosic textiles. Maleinized soybean oil (MSO), having an acid value of 156 mg KOH/g, was neutralized with ammonium hydroxide to render it water soluble. Infrared spectroscopy indicated the formation of ester linkages during the cure of MSO treated textiles. Therefore, the formation of anhydride and amide intermediates upon heating ammonia neutralized MSO were investigated. Construction of the cyclic anhydride was observed as a pathway to esterification; however, amidation was not observed among this ammonia neutralized MSO. Neutralization of MSO with ethanolamine and triethylamine yielded secondary and tertiary amides but not esters at 160 °C.
Keywords: Vegetable oil macromonomer; Maleinized soybean oil; Cotton; Esterification; Ammonia; Amine; Amidation; Succinic anhydride; Neutralized

Ozonolysis of Canola Oil: A Study of Product Yields and Ozonolysis Kinetics in Different Solvent Systems by Tolibjon S. Omonov; Ereddad Kharraz; Jonathan M. Curtis (689-705).
The use of ozonolysis has been proposed as a step in the production of vegetable-oil-based polyols as replacements for the equivalent petrochemicals. As part of an evaluation of the commercial viability of ozonolysis, the intermediates and products formed from the ozonolysis of canola oil using different protic and aprotic solvents and solvent mixtures were systematically studied by GC-FID and size-exclusion chromatography with refractive index detection (SEC-RI). It was found that the use of an aprotic solvent (ethyl acetate) leads to the formation of oligomeric ozonolysis products whereas alcohols and/or mixtures of ethyl acetate with alcohols for the ozonolysis of canola oil do not form high molecular weight compounds. In addition, when ethyl acetate is used as the solvent, the formation of carboxylic acids is observed in the early stages of ozonolysis whereas the use of alcohols significantly reduces acid formation. As expected, extending the ozonolysis time led to extensive carboxylic acid formation, especially using ethyl acetate as a solvent. It was found that the optimum time for the complete ozonolysis of canola oil was largely independent of the solvent used for ozonolysis. However, the yield of ozonolysis products differs considerably depending on the solvents employed. Overall, a clear correlation between the ozonolysis time, product yields and the reaction exothermicity was observed.
Keywords: Canola oil; Ozonolysis; Oxidative cleavage

Supercritical CO2 Extraction of Flax Lignans by Lauren M. Comin; Feral Temelli; Marleny Aranda Saldaña (707-715).
Lignans, such as flaxseed secoisolariciresinol diglucoside (SDG), have been implicated in the prevention of hormonally related cancers and other prevalent diseases. Lignans are typically extracted using organic solvents, which must then be removed from the extract. Supercritical carbon dioxide (SC-CO2) is a non-toxic, inexpensive solvent, which, when combined with polar modifiers, can be used to extract polar phenolic compounds, such as SDG. The effects of processing conditions and pre-treatment on the extraction of SDG using SC-CO2 were investigated. Extraction from defatted flaxseed was performed with SC-CO2 modified with ethanol at levels of 0, 10 and 20 mol% at different temperature (40, 50 and 60 °C) and pressure (35, 40 and 45 MPa) conditions. Extracts were analyzed using RP-HPLC. The condition (7.8 mol% ethanol, 45 MPa and 60 °C) which produced the maximum CO2 loading of SDG (0.49 μg/g CO2) was used for the pre-treatment study, in which flaxseed defatted with petroleum ether and SC-CO2, full-fat hulls, defatted hulls and pre-hydrolyzed flaxseed were used. Temperature, pressure and solvent modifier level had no significant effect (p > 0.05) on the SDG loading of CO2. However, pre-hydrolyzed seed resulted in a significantly (p ≤ 0.05) higher CO2 loading of SDG (3.8 μg/g CO2) compared to the other treatments studied. The yields obtained represented only a small fraction of the original lignan content (15 mg/g petroleum ether defatted flaxseed).
Keywords: Flaxseed; Lignan; Secoisolariciresinol diglucoside (SDG); Supercritical carbon dioxide (SC-CO2)

Response Surface Modeling of Processing Parameters for the Preparation of Phytosterol Nanodispersions Using an Emulsification–Evaporation Technique by Wai-Fun Leong; Kok-Whey Cheong; Oi-Ming Lai; Kamariah Long; Yaakob B. Che Man; Misni Misran; Chin-Ping Tan (717-725).
The purpose of this study was to optimize the production parameters for water-soluble phytosterol nanodispersions. Response surface methodology (RSM) was employed to model and optimize three of the processing parameters: mixing time (t) by conventional homogenizer (1–20 min), mixing speed (v) by conventional homogenizer (1,000–9,000 rpm) and homogenization pressure (P) by high-pressure homogenizer (0.1–80 MPa). All responses [i.e., mean particle size (PS), polydispersity index (PDI) and phytosterols concentration (Phyto, mg/l)] fitted well to a reduced quadratic model by multiple regressions after manual elimination. For PS, PDI and Phyto, the coefficients of determination (R 2) were 0.9902, 0.9065 and 0.8878, respectively. The optimized processing parameters were 15.25 min mixing time, 7,000 rpm mixing speed and homogenization pressure 42.4 MPa. In the produced nanodispersions, the corresponding responses for the optimized preparation conditions were a PS of 52 nm, PDI of 0.3390 and a Phyto of 336 mg/l.
Keywords: Phytosterol; Nanodispersion; Response surface methodology; High-pressure

Aqueous Enzymatic Extraction of Oil and Protein Hydrolysates from Roasted Peanut Seeds by Shao Bing Zhang; Qi Yu Lu; Hongshun Yang; Yu Li; Shuai Wang (727-732).
To evaluate the effects of the roasting process on the extraction yield and oil quality, peanut seeds were roasted at different temperatures (130–220 °C) for 20 min prior to the aqueous extraction of both oil and protein hydrolysates with Alcalase 2.4 L. Roasting temperatures did not significantly affect the yields of free oil, whereas the temperature of 220 °C led to a reduced recovery of protein hydrolysates. The color and acid values of peanut oils did not change significantly with roasting temperatures. The enzyme-extracted oil with roasting at 190 °C had a relatively low peroxide value, a strong oxidative stability, and the best flavor score. Using the same seed-roasting temperature (190 °C), quality attributes such as color, acid and peroxide values, phosphorus content and oxidative stability of the enzyme-extracted oil were better than those of the oil obtained by an expeller. After the peanut seeds were roasted at 190 °C for 20 min, with a seeds-to-water ratio of 1:5, an enzyme concentration of 2%, and an incubation time of 3 h, the yields of free oil and protein hydrolysates were 78.6 and 80.1%, respectively. After demulsification of the residual emulsion by a freezing and thawing method, the total free oil yield increased to 86–90%.
Keywords: Aqueous enzymatic extraction; Peanut oil; Peanut protein; Roasting temperature

Pilot Plant Recovery of Soybean Oleosome Fractions by an Enzyme-Assisted Aqueous Process by Lili T. Towa; Virginie N. Kapchie; Catherine Hauck; Hui Wang; Patricia A. Murphy (733-741).
An aqueous enzymatic procedure for oleosome fractionation from 25 g of soy flour was developed in our laboratory. This fractionation procedure was evaluated with 75 kg using pilot plant equipment to evaluate the effect of the scale-up on the recovery, proximate composition, soybean storage protein profiles, and subcellular microstructure of oleosome fractions. The process included enzymatic hydrolysis, grinding, and centrifugation, respectively. Pilot-scale grinding and centrifugation of the slurry were accomplished with a Stephan® Microcut mill grinder and a three phase decanter. A blender and swinging bucket rotor were used for the laboratory-scale fractionation. The oleosome fractions recovered in the pilot plant were similar in oil and protein content to those obtained in the laboratory. The pilot-scale process resulted in a significantly higher oil yield of 93.40% as total oleosomes compared to that of 76.83% achieved in the laboratory. Urea–SDS gel electrophoresis of proteins extracted from the oleosomes and supernatant from the pilot-scale fractionation had similar profiles to those obtained in the laboratory. Electron microscopy verified that the structure of isolated oleosomes was virtually identical with that of in situ oleosomes. This work confirms that large-scale fractionation of oleosomes from full fat soybean flour can be accomplished.
Keywords: Soy oleosomes; Oil yield; Pilot plant process