Potato Chip Quality and Frying Oil Stability of High Oleic Acid Soybean Oil

High oleic soybean (HOSBO) and low linolenic acid soybean (LLSBO) oils were evaluated individually and in a 1:1 blend along with cottonseed oil (CSO) to determine frying oil stabilities and the flavor quality and stability of potato chips. Potato chips were fried in the oils for a total of 25 h. Potato chips and oils were sampled periodically for sensory data, gas chromatographic volatile compounds, free fatty acids, and total polar compounds. Total polar compounds levels decreased with increasing amounts of oleic acid. The LLSBO had the highest overall increase (17.3%) in total polar compounds from 0 to 25 h of frying. Flavor evaluations of fresh and aged (0, 1, 3, 5, and 7 wk at 25 °C) potato chips showed differences between potato chips fried in different oil types. Potato chips fried in either LLSBO or in the 1:1 blend had significantly higher intensities of deep fried flavor than the chips fried in HOSBO. Potato chips fried in HOSBO, which had 2% linolenic acid and 1.3% linoleic acid, had significantly higher fishy flavor intensity than chips fried in the other oils. The presence of linoleic acid at a level lower than the amount of linolenic acid probably allowed for the fishy flavors from the degradation of linolenic acid in HOSBO to become more apparent than if the linoleic acid level was higher than linolenic acid. Hexanal was significantly higher in potato chips fried in LLSBO than in the chips fried in the other oils, indicating low oxidative stability during storage. Blending HOSBO with LLSBO in a 1:1 ratio not only improved flavor quality of chips compared with those fried in HOSBO, but also improved oil fry life and oxidative stability of chips compared with LLSBO.     

Inactivation of pathogenic bacteria by cucumber volatiles (E,Z)-2,6-nonadienal and (E)-2-nonenal

The effects of (E,Z)-2,6-nonadienal (NDE) and (E)-2-nonenal (NE) on Bacillus cereus, Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Typhimurium were investigated. A suspension of each organism of 6 to 9 log CFU/ml was incubated for 1 h at 37 degrees C in brain heart infusion solution that contained 0 to 500 or 1,000 ppm of NDE or NE. Depending on concentration, exposure to either NDE or NE caused a reduction in CFU of each organism. Treatment with 250 and 500 ppm NDE completely eliminated viable B. cereus and Salmonella Typhimurium cells, respectively. L. monocytogenes was the most resistant to NDE, showing only about a 2-log reduction from exposure to 500 ppm for 1 h. Conversely, this concentration of NDE caused a 5.8-log reduction in E. coli O157:H7 cells. NE was also effective in inactivating organisms listed above. A higher concentration of NE, 1,000 ppm, was required to kill E. coli O157:H7, L. monocytogenes, or Salmonella Typhimurium compared with NDE. In conclusion, both NDE and NE demonstrated an apparent bactericidal activity against these pathogens.     

单、双脂肪酸甘油酯(亚麻酸)乳液的制备及特性研究

针对单、双脂肪酸甘油酯（亚麻酸）极易氧化的特点,该研究以乳清浓缩蛋白（WPC）、大豆分离蛋白（SPI）、酪蛋白酸钠（SC）和吐温80（T80）为乳化剂制备乳液,考察乳化剂类型对乳液的理化性质、氧化稳定性和消化特性的影响。结果表明,乳液均具有较小的粒径（131.97~224.87 nm）,且在两周贮藏期内保持稳定。乳液包载能够提高单、双脂肪酸甘油酯（亚麻酸）的氧化稳定性,相比T80（过氧化值为377.40 mmol/kg）,蛋白质对油脂的氧化保护效果更好,其中SPI稳定的乳液过氧化值最低为197.73 mmol/kg。体外模拟消化试验表明,乳化剂类型对游离脂肪酸的释放影响较小,但蛋白稳定的乳液在胃消化阶段更容易发生液滴聚集;亚麻籽油的脂质水解程度最低为23.93%,而单、双脂肪酸甘油酯（亚麻酸）的初始消化速度更快,最终脂解程度更高（46.33%）。因此,蛋白质乳液能有效提高单、双脂肪酸甘油酯（亚麻酸）的氧化稳定性,且单、双脂肪酸甘油酯（亚麻酸）相比亚麻籽油具有更好的消化效率,有望替代亚麻籽油作为人体亚麻酸的食物来源。     

不同大豆品种提取油脂氧化稳定性研究

该实验采用自动索氏抽提仪对不同大豆品种提取油脂,气相色谱分析其脂肪酸组成,酸败仪测其氧化稳定性方法,研究不同大豆品种提取油脂脂肪酸组成与其氧化稳定性之间关系。实验发现,一般而言,油酸、亚油酸含量较高大豆品种油脂氧化稳定性相对较好,亚麻酸含量较高品种油脂氧化稳定性较差;但有些大豆品种,如:栽培种169号,野生种y112号大豆脂肪酸组成,其亚麻酸含量较高,分别为10.89%、13.45%,测得诱导时间却较长,分别为8.15h、8.25h;分析原因,发现其中含有天然抗氧化成分,可阻止或延缓油脂氧化。     

Chemical and physical characteristics, fatty acid composition and toxicity of buffalo gourd oil, Cucurbita foetidissima

In this study, Cucurbita foetidissima (Buffalo gourd) was investigated as a source of edible oil for human consumption. The seeds are rich in oil (28%) as well as protein (29%). General chemical tests such as the iodine number, saponification number, acid value and others were favourably compared to values of other edible oils. The analysis of the crude oil by means of gas liquid chromatography showed that it is rich in linoleic acid (63%) and has a high unsaturated to saturated fatty acid ratio. The high percentage of linoleic acid and the extremely low percentage of linolenic acid indicate that the oil could be a valuable edible oil, with a relatively good stability. Chicken feeding experiments showed that the oil did not contain any toxic substances causing death or interfering with growth rate and feed conversion.     

Fatty acid composition of meat from typical lamb production systems of Spain, United Kingdom, Germany and Uruguay

The fatty acid composition of commercial lambs from different production systems of Spain, Germany, United Kingdom and of two types of Uruguayan lambs (heavy and light) was studied. Concentrate fed lambs, as Spanish lambs, displayed the highest proportions of linoleic acid (C18:2), while Uruguayan lambs, reared under extensive grazing conditions, showed the highest proportions of linolenic acid (C18:3), due to the great concentration of this fatty acid in grass. German and British lambs, which were fed grass and concentrate, displayed intermediate proportions of linolenic acid (C18:3). Heavy Uruguayan lambs had higher intramuscular fat content (5.92%) than German (4.25%) and British (4.32%) lambs, and this content was twofold higher than light lambs (Spanish (2.41%) and light Uruguayan (3.05%)). Heavy Uruguayan, German and British lambs had a low polyunsaturated/saturated (P/S) ratio due to their high saturated fatty acid (SFA) content and proportion. Principal component analysis was performed to study the relationship between fatty acids. Spanish lambs were clearly separated from the other types and were situated close to the proportions of short chain and n-6 fatty acids and n-6/n-3 ratio in the data plot for fatty acid proportions. Light Uruguayan lambs were located close to long chain fatty acids, and heavy Uruguayan and British lambs were placed near the antithrombotic potential (ATT), stearic acid (C18:0), SFA and conjugated linoleic acid (CLA) proportions. German lambs were located between Spanish lambs and the other types.     

CHARACTERIZATION OF LIPOXYGENASE FROM MACKEREL (SCOMBER SCOMBRUS) MUSCLE

The polyunsaturated fatty acids (PUFA) in fish render them potentially susceptible to enzymatic oxidation. Lipoxygenase (LOX) activity from mackerel (Scomber scombrus) was characterized with respect to pH stability and activity, temperature stability, buffer and substrate preferences and inhibition patterns. The partially purified enzyme was stable over the pH range 4.0–11.0 and had a pH-activity optimum pH of 5.6. Mackerel muscle LOX (mmLOX) was stable at 0–50C but lost activity at higher temperatures. Enzymatic assays using different buffers revealed that MES-NaOH and Bistris-HCl were the suitable buffers for reaction. Substrate preference was for unoleic acid compared to linolenic, arachidonic, docosahexaenoic oroleicacid. K_m values were 0.69 and 0.57 mM and V_max was 0.058 and 0.019 μmol mm^-1, for linoleic and linolenic acid, respectively. mmLOX was inhibited by classical LOX inhibitors such as BHA, BHT, NDGA, esculetin and also by the heme protein inhibitor KCN. Values for the IC₅₀ (concentration for half maximal inhibition) was between 0.02 μM and 41 μM.
Normal phase high performance liquid chromatography (HPLC) analyses revealed that both 13- and 9-hydroperoxides were formed during mmLOX catalyzed oxidation with Unoleic acid substrate although a higher proportion of the 13-isomer was formed. With enzymes from different mackerel tissues (skin, gills and muscle), mmLOX had the highest hydroperoxide forming ability.     

不同制取方法对亚麻籽油和亚麻籽粕品质影响研究

以未处理和焙炒处理后的亚麻籽为原料,采用溶剂浸提、液压压榨和螺旋压榨三种制油工艺,得到六种亚麻籽油和粕,探讨不同制取方法对亚麻籽油和亚麻籽粕品质的影响。结果表明：焙炒溶剂浸提法样品出油率最高（34.50%）;在三种制油工艺中,焙炒处理后制得的亚麻籽油过氧化值和酸价均高于未处理组,但焙炒前处理可以提高亚麻籽油中总酚和维生素E含量;此外,制取工艺对亚麻籽油的氧化稳定性也有一定影响,其中螺旋压榨油氧化稳定性最好,且同种制取工艺间焙炒前处理可以增强亚麻籽油的氧化稳定性;制取工艺和焙炒前处理对亚麻籽油中亚麻酸含量和不饱和脂肪酸含量影响不显著,但焙炒处理组中的吡嗪、吡咯物质分别比未处理组高5.1%、15.8%、9.3%,未处理组中的醇类物质分别比焙炒处理组高6.1%、11.8%、3.7%。不同制取方法得到的亚麻籽粕中,未处理液压粕粗脂肪、粗蛋白和NSI（氮溶解系数）最高,焙炒螺旋压榨粕木脂素聚合物含量（16.70%）最高,且NSI也处于较高水平（33.13%）;焙炒螺旋亚麻籽粕木脂素聚合物对DPPH、ABTS自由基清除率的半数清除率（IC50）分别为0.49 mg/mL和0.88 mg/mL。本研究结果对亚麻籽油的产业发展和亚麻籽加工副产物的利用提供了参考。     

我国10种铁核桃油的组成特性和氧化稳定性

选取我国新疆、云南和西藏三大主要产区的10种代表性铁核桃样品,制备铁核桃油,测定了铁核桃油的脂肪酸组成,总酚、生育酚、植物甾醇含量及氧化稳定性,采用化学计量学的方法对铁核桃油的组成特性进行分析。结果表明:我国铁核桃油的脂肪酸主要为亚油酸(54.84%~66.97%),油酸(15.88%~26.04%),亚麻酸(6.82%~12.25%)和棕榈酸(5.12%~7.62%)。微量伴随物生育酚含量176.89~832.86 mg/kg、植物甾醇含量530.96~1 095.47 mg/kg、总酚含量1.42~15.84 mg/kg,氧化稳定性指数(OSI)为0.55~3.39 h。基于回归分析发现,影响铁核桃油氧化稳定性的主要组成物质是亚油酸、亚麻酸、γ-生育酚和总酚。     

Effect of vitamin C addition to ground beef from grass-fed or grain-fed sources on color and lipid stability, and prediction of fatty acid composition by near-infrared reflectance analysis

Research was conducted to determine the effect of postmortem vitamin C addition (VITC) versus no VITC (CONTROL) to ground beef from grass-fed (GRASS) or grain-fed (GRAIN) sources on color and lipid stability during 8 days of illuminated display at 4 °C. The use of near-infrared reflectance (NIR) spectroscopy to predict the fatty acid composition of ground beef and its potential to discriminate samples from different nutritional backgrounds were also evaluated. Total lipid content of ground beef was 53% lower (P<0.05) for GRASS than GRAIN. Ground beef from GRASS had greater (P<0.01) percentages of saturated (SFA) and polyunsaturated (PUFA) fatty acids, and lower (P<0.01) percentages of monounsaturated (MUFA) fatty acids than GRAIN. For GRAIN, VITC reduced (P<0.01) lipid oxidation, and resulted in darker (P<0.01) and redder (P<0.01) color of the ground beef from 2 to 8 days of display compared to CONTROL. For GRASS, lipid oxidation did not differ (P>0.05) for VITC and CONTROL. VITC improved (P<0.01) color stability by prolonging more red color in GRASS during 8 days of display. Results from partial least squares modeling showed accurate predictions using NIR for total saturated [standard error of performance (SEP=1.16%), coefficient of determination on the validation set (r(2)=0.87)] and unsaturated (SEP=1.18% and r(2)=0.90) fatty acid contents of ground beef, as well as the composition of stearic, oleic, and linolenic (SEP=1.2%, 1.27%, and 0.07%; r(2)=0.91, 0.92, and 0.93, respectively). However, the composition of other individual fatty acids was poorly predicted. VITC was effective in retarding pigment oxidation in ground beef from both GRAIN and GRASS; however, VITC reduced lipid oxidation in GRAIN samples only, despite higher PUFA percentages in GRASS. NIR can be used to predict accurately the content of total saturated and unsaturated, and stearic, oleic, and linolenic fatty acids in ground beef. NIR showed potential to discriminate meat samples originating from different feeding production systems.     

Production and stability of chlorine dioxide in organic acid solutions as affected by pH, type of acid, and concentration of sodium chlorite, and its effectiveness in inactivating Bacillus cereus spores

We studied the production and stability of chlorine dioxide (ClO₂) in organic acid solutions and its effectiveness in killing Bacillus cereus spores. Sodium chlorite (5000, 10,000, or 50,000 μg/ml) was added to 5% acetic, citric, or lactic acid solution, adjusted to pH 3.0, 4.0, 5.0, or 6.0, and held at 21 °C for up to 14 days. The amount of ClO₂ produced was higher as the concentration of sodium chlorite was increased and as the pH of the acid solutions was decreased. However, the stability in production of ClO₂ was enhanced by increasing the pH of the organic acid solutions. To evaluate the lethal activity of ClO₂ produced in various acid solutions as affected by acidulant and pH, suspensions of B. cereus spores were treated at 21 °C for 1, 3, 5, or 10 min in hydrochloric acid or organic acid solutions (pH 3.0, 4.0, 5.0, or 6.0) containing ClO₂ at concentrations of 100, 50, or 25 μg/ml. Populations of viable spores treated with ClO₂ at concentrations of 100 or 50 μg/ml in organic acid solutions decreased more rapidly than populations treated with the same concentrations of ClO₂ in HCl. Rates of inactivation tended to increase with higher pH of ClO₂ solutions. Results show that ClO₂ formed in organic acid solutions has higher stability and is more lethal to B. cereus spores than ClO₂ formed at the same concentration in HCl solution. This finding emphasizes the benefits of using organic acid solutions to prepare ClO₂ intended for use as an antimicrobial.     

Effects of Fatty Acids on the Oxidative Stability of Soybean Oil

Effects of 0, 0.5, and 1.0% levels of stearic, oleic, linoleic or linolenic acid or octadecane on the oxidative stability of soybean oil were determined by a combination of peroxide values and measurements of volatile compounds and oxygen in the headspace of samples by gas chromatography. These fatty acids showed similar prooxidant activities which were not statistically different at α= 0.05. However, octadecane which had the same number of carbons as stearic, oleic, linoleic or linolenic acid but no carboxylic group, did not show prooxidant activity.     

Capillary gas chromatography analysis of Ethiopian mustard to determine variability of fatty acid composition

Ethiopian mustard (Brassica carinata A. Braun) is an oil crop grown in Ethiopia. However, the oil is considered low quality, as it contains long chain monounsaturated fatty acids, mainly erucic acid. High erucic acid content is beneficial for the polymer industry, whereas low erucic acid is recommended for food purposes. Both linoleic and linolenic acids are essential fatty acids; however, less than 3% linolenic acid is preferred for oil stability. The objectives of this study were to determine fatty acid composition of Ethiopian mustard to determine the range of genetic diversity for these traits. The genotypes were analysed by capillary gas chromatography (CGC). Twenty‐six fatty acids were identified. In all accessions, the predominant fatty acids were erucic, linoleic, α‐linolenic and oleic, followed by gadoleic and palmitic. To a lesser extent stearic, vaccinic, nervonic and behenic acids were found in all accessions. Significant correlations were found between palmitic acid and stearic acid (positive), between erucic acid and palmitic, stearic, vaccinic, oleic, linoleic and α‐linolenic acids (negative) and eicosenoic acid (positive). Selection and hybridization techniques can be applied to modify the oil content of Ethiopian mustard, considering the variability observed. Copyright © 2004 Society of Chemical Industry     

Effect of excess dietary iron on lipid composition of calf liver, heart, and skeletal muscle

Effect of excess dietary iron on lipid composition of calf liver, skeletal muscle, and heart was assessed. High dietary iron (5000 versus 100 ppm in milk replacer DM) had no effect on the relative proportion of lipid classes in liver or their unsaturated fatty acid composition. In muscle some minor lipid components were reduced and cholesterol and sphingomyelin increased. Excessive iron had a marked effect, however, on heart lipid composition, reducing total lipids and almost all lipid classes; triglycerides, sphingomyelin, and lysophosphatidylcholine were increased. Characteristically, sphingomyelin increases in cell membranes in response to aging and numerous pathological conditions. High dietary iron reduced linolenic acid in phosphatidyl-ethanolamine and phosphatidylcholine of both skeletal and cardiac muscle. This may have resulted from iron-caused ethane production from autoxidation of linolenic acid or other n-3 family fatty acids, an effect known to occur in the rat. Linoleic and arachidonic fatty acids appeared to be unaffected. Plasmalogens in muscle and heart phosphatidylethanolamine and phosphatidylcholine were increased by high iron intake. As these alk-1-enyl ethers protect cells from oxidation and radiation damage, their synthesis may have been increased in response to stress from excessive iron. The results indicate that a relatively high concentration of vitamin E may be required in calf milk replacer when excessive iron is present.     

Fresh forage and solin supplementation on conjugated linoleic acid levels in plasma and milk

Two experiments were run concurrently to determine the effect of fresh forage consumption on the production and proportions of plasma and milk fat vaccenic acid (VA), conjugated linoleic acid (CLA), and linolenic acid in diary cattle. In experiment 1, the cows consumed 50, 65, and 80% of their feed intake as pasture with the remainder of intake as a barley-based concentrate. The proportion of VA in milk fatty acids increased 12% when pasture intake increased from 50 to 65% of total dry matter intake and VA, CLA, and linolenic acid proportions increased 26, 18, and 27%, respectively, as pasture increased from 65 to 80% of dietary intake. In experiment 2, fresh forage was compared to conserved hay (cut from the same pasture the previous summer) to determine the effect on plasma and milk fat VA, CLA, and linolenic acid. Also, the effect of crushed solin seed (a flax cultivar that is high in linoleic acid) supplementation to the fresh forage diet was determined. Fresh forage compared to conserved hay in the diet, increased the proportion of CLA in the plasma very low density lipoproteins (VLDL) fraction by 71% but had no effect on linolenic acid. Supplementation of the fresh forage diet with a linoleic acid source increased VA and CLA in the plasma VLDL fraction 25 and 58% and slightly decreased the proportion of linolenic acid. Fresh forage, compared to conserved hay, increased milk fat VA and CLA proportions by 22 and 15%. Supplementing the fresh forage diet with linoleic acid from crushed solin seed further increased milk fat VA and CLA proportions 41 and 25%. Solin supplementation in a lactation diet is a superior method to increase CLA levels in milk fat than feeding fresh forage alone.     

Composition, Functionality, and Sensory Evaluation of Eggs from Hens Fed Dietary Menhaden Oil

Enrichment of omega-3 fatty acid content of egg yolk may increase consumer acceptance of egg products if eggs maintain characteristic functionality, exhibit compositional stability, and are sensorially acceptable. The diet of laying hens was enriched with 3% menhaden oil. Arachidonic acid (20:4n-6) was decreased 70.2%, and linolenic (18:3n-3) and docosahexaenoic acid (22:6n-3) were increased 78.5% and 356%, respectively, in egg yolk. Eicosapentaenoic acid (20:5n-3) was also incorporated into test egg yolk as compared to nondetectable levels in control eggs. Cooking did not alter the fatty acid composition of eggs nor were functional properties of test eggs affected. Panelists differentiated n-3 enriched eggs from controls (P ≤ 0.01) when scrambled but not when hard cooked.     

Relationship between fat depots in carcasses of beef bulls and effect on meat colour and tenderness

The growth and the effects of four species of staphylococci and six lactic acid bacteria (LAB) of the genus Carnobacterium, Lactobacillus and Pediococcus on unsaturated free fatty acids were studied. The strains were grown in complex medium supplemented either with oleic, linoleic or linolenic acids. Growth was followed and oxidation of the substrates measured by TBARS. The strains of Staphylococcus xylosus 873, 16, Staphylococcus warneri 863 and Staphylococcus saprophyticus grew well on all the substrates. Whereas, the growth of the two strains of Staphylococcus carnosus and Staphylococcus xylosus 831 was inhibited in the media with linolenic acid. The addition of manganese to this media allowed good growth of these strains. All the LAB did not grow well in the media with linoleic acid, but their growth was favoured by addition of manganese to the media. Under our conditions, only linoleic and linolenic acids were oxidised. All the strains had no prooxidant activity. All the staphylococci limited oxidation of linoleic acid and had a small effect on linolenic acid. LAB did not limit oxidation of linoleic acid. With manganese in the media: the oxidation of the sterile controls was delayed for 2 days and then increased; strains of S. carnosus and S. xylosus inhibited oxidation of linolenic acid; and Lactobacillus plantarum and Pediococcus pentosaceus limited oxidation of linoleic acid. The two Carnobacterium, whatever the conditions, had no antioxidant properties.     

Chemical Composition Analysis,Sensory, and Feasibility Study of Tree Peony Seed

Eight wild species in Sect. Moutan DC (tree peony) of the genus Paeonia grown in natural habitats and 1 cultivated specie were investigated to analyze their fatty acid and bioactive phenolic compound profiles. For fatty acid composition, P. ludlowii contained the lowest α‐linolenic acid (27.68%) and P. jishanensis contained the highest (51.96 %) content of the 9 species. For phenolic compounds, P. qiui contained the highest resveratrol (2.12 mg/g), P. delavayi contained the highest β‐gentiobiosylpaeoniflorin (26.23 mg/g), and P. ostii contained the highest paeoniflorin (23.66 mg/g). P. ostii was selected to perform a feasibility study because of its relatively high level of α‐linolenic acid 46.53%, low in ω‐6 to ω‐3 ratio of 1:2, and high level of the preferred bioactive phenolic compounds l including paeoniflorin and resveratrol. Physical pressing and refining process were conducted to obtain P. ostii seed oil. It exhibited bland sensory attributes described as slight grassy, very slight nutty, no painty or fishy aroma and slight grassy, slight nutty flavor with a very slight throat catch. Tocol results reported high level in tree peony seed oil 223.5 ± 13.65 mg/100 g with γ‐tocopherol 70.1 ± 2.14 mg/100 g, and γ‐tocotrienol 149.6 ± 15.83 mg/g. Because of the high total tocol, γ‐tocopherol and γ‐tocotrienol levels, and tree peony seed oil exhibited better oxidation stability than flaxseed oil even with similar α‐linolenic acid levels. In addition, high levels of γ‐tocopherol and γ‐tocotrienol can introduce therapeutic effects such as antiinflammation and antioxidation. Therefore, this study showed that tree peony seed oil has a great potential to be used in edible oil, nutraceutical supplement, and other health care products.     

大豆脂肪氧合酶催化合成亚麻酸氢过氧化物的研究

大豆脂肪氧合酶催化亚麻酸生成亚麻酸氢过氧化物,在氢过氧化物裂解酶的作用下可生成具有青草自然风味的化合物.为了得到转化率高、纯度高的亚麻酸氢过氧化物,研究了反应温度、pH、亚麻酸浓度、加酶量、搅拌速度和氧气压力等对亚麻酸氢过氧化物转化率的影响.实验得出:当反应温度为4℃,pH为9.0,亚麻酸浓度为0.025 mol/L,加酶量为2.5 U/mL,搅拌速度为800 r/min,氧气压力为0.2 MPa时,生成的亚麻酸氢过氧化物的转化率和纯度分别为82.3%和87.01%.