Oxidative stability of oil from blubber of harp seal (Phoca groenlandica) as assessed by NMR and standard procedures

Oils from seal blubber and cod liver were extracted, refined and bleached in a laboratory scale process. Oxidative stability of oils was evaluated over a 16-day period under accelerated oxidation conditions at 65°C. Peroxide value (PV), contents of conjugated dienes (CD) and trienes (CT), 2-thiobarbituric acid reactive substances (TBARS) and p-anisidine values (AnV) were determined. In addition, NMR spectroscopy was used to monitor relative changes in the proton pattern of the fatty acids of oils during storage. Cod liver oil showed higher PV, CD, CT and TBARS values as compared with seal blubber oil. The ratio of aliphatic to olefinic protons in both oils determined by NMR spectroscopy increased steadily over the entire length of the storage period, indicating progressive oxidation of unsaturated fatty acids in both oils. A significant correlation (P ≤0·05) was found between these ratios and TOTOX values (2PV + AnV) for both oils, thus suggesting that NMR methodology can be used as an effective means to simultaneously estimate both primary and secondary oxidation changes.     

Fatty acids and triacylglycerols in the seed oils of Saudi Arabian date (Phoenix dactylifera L.) palms

Total lipids, fatty acids and triacylglycerols in seeds of the four Saudi Arabian date cultivars ‘Anbra’, ‘Megadwel’, ‘Sacai’ and ‘Sfwai’ were analysed. Total lipid contents ranged between 7.3 and 8.6%. Oleic, lauric and myristic acid represented the most abundant fatty acids in date seed oil. HPLC-DAD-ESI-MSⁿ analysis enabled the identification of 40 triacylglycerols with equivalent carbon number (ECN) 36–54, of which 17 were detected for the first time. Triacylglycerols mainly comprised LaOL, LaLaL, LaML, MML/LaPL and LaOO. ‘Anbra’ oil was characterised by highest proportions of saturated fatty acids and triacylglycerols with ECN 36 and 48–54. Unsaturated fatty acids prevailed in the three remaining varieties. Elevated proportions of triacylglycerols with medium ECNs were found in ‘Megadwel’ and ‘Sfwai’ oils. Aside from highest total lipid contents, ‘Sacai’ seeds predominantly contained triacylglycerols with low ECNs. Multivariate statistical analyses elucidated varietal influences on the fatty acid and triacylglycerol composition of date seed oil.     

Stabilizing Oils from Smoked Pink Salmon (Oncorhynchus gorbuscha)

ABSTRACT:  Smoking of meats and fish is one of the earliest preservation technologies developed by humans. In this study, the smoking process was evaluated as a method for reducing oxidation of pink salmon ( Oncorhynchus gorbuscha ) oils and also maintaining the quality of oil in aged fish prior to oil extraction. Salmon heads that were subjected to high temperatures (95 °C) during smoking unexpectedly produced oils with fewer products of oxidation than their unprocessed counterparts, as measured by peroxide value (PV), thiobarbituric acid reactive substances (TBARS), and fatty acids (FA). Higher temperatures and longer smoking times resulted in correspondingly lower quantities of oxidative products in the oils. Fatty acid methyl ester (FAME) analysis of smoke-processed oils confirmed that polyunsaturated fatty acids (PUFA) were not being destroyed. Smoke-processing also imparted antioxidant potential to the extracted oils. Even when antioxidants, such as ethoxyquin or butylated hydroxytoluene, were added to raw oils, the smoke-processed oils still maintained lower levels of oxidation after 14 d of storage. However, decreased antioxidant capacity of smoke-processed oils was noted when they were heated above 75 °C. Vitamin studies supported the antioxidant results, with smoke-processed oils displaying higher levels of α-tocopherol than raw oils. Results suggest that smoking salmon prior to oil extraction can protect valuable PUFA-rich oils from oxidation. Improved preservation methods for marine oils may extend their usefulness when added as a supplement to enhance levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in foods.     

Comparison of fatty acid profile changes between unroasted and roasted brown sesame (Sesamum indicum L.) seeds oil

The conditions of roasting are the key step in manufacturing Sesame (Sesamum indicum L.) oil. Roasting sesame seeds changed its oil, moisture, and ash content. In oils from unroasted and roasted seeds, nine fatty acids analyzed by gas chromatography-mass spectrometry. The fatty acids composition were changed in both oils. Oleic and linoleic changed in large amount, but changes for other fatty acids were small. ¹H and ¹³C NMR analysis showed the frequency changes for both oils, the roasting condition caused to shift the frequency to lower degree.     

Blending of corn oil with black cumin (Nigella sativa) and coriander (Coriandrum sativum) seed oils: Impact on functionality, stability and radical scavenging activity

Blends (10% and 20%, w/w) of black cumin seed oil (BCSO) and coriander seed oil (CSO) with corn oil (CO) were formulated. Oxidative stability (OS) and radical scavenging activity (RSA) of CO and blends stored under oxidative conditions (60 °C) for 15 days were studied. By increasing the proportion of BCSO and CSO in CO, levels of polyunsaturated fatty acids (PUFA) decreased, while monounsaturated fatty acids (MUFA) content increased. Progression of oxidation was followed by measuring peroxide value (PV), conjugated dienes (CD) and conjugated trienes (CT). Inverse relationships were noted between PV and OS at termination of storage. Levels of CD and CT in CO, and blends, increased with increase in time. CO:BCSO and CO:CSO blends gave 12-22% and 26-36% inhibition of DPPH radicals, respectively. Oxidative stability of oil blends were better than CO, most likely as a consequence of changes in fatty acids and tocopherols’ profile, and minor bioactive lipids (e.g., sterols and phenolics) found in coriander and black cumin oils.     

Stereospecific Positional Distribution of Fatty Acids of Camellia (Camellia japonica L.) Seed Oil

Abstract: The stereospecific positional distribution of fatty acids of camellia seed oil (also called camellia oil) was determined. The camellia oil was mainly composed of neutral lipids (88.2%), and the oleic acid (86.3%) was found to be a major fatty acid of neutral lipids. In the glycolipids and phospholipids, the oleic acid was also found to be a major fatty acid at 62.5% and 54.2%, respectively. The oleic acid was distributed abundantly in all sn‐1, 2, and 3 positions. It was found that the oleic acid was present more at sn‐2 (93.6%) and 3 positions (94.7%), than at sn‐1 position (66.0%). Practical Application: The information of stereospecific positional distribution of fatty acids in the camellia oil can be used for the development of the structured lipids for food, pharmaceutical, and medical purposes.     

Changes in fatty acid and essential oil composition of sage (Salvia officinalis L.) leaves under NaCl stress

Fatty acids and essential oils from hydroponically cultivated Salvia officinalis leaves were analyzed by GC and GC–MS. Four different levels of NaCl (25, 50, 75 and 100 mM) were applied. The first results showed that salt treatment reduced significantly the plant growth by 61% and the total fatty acids (TFA) content by 32% at 100 mM NaCl. Alpha-linolenic, gadoleic, palmitic and oleic acids were the major fatty acids. Moreover, the polyunsaturated fatty acids decreased, while the monounsaturated ones increased with respect to increasing salinity. Regarding the essential oil composition, the main compounds were α-and β-thujone, 1,8-cineole, camphor, α-humulene, viridiflorol and manool at all salt treatments. The yield had a maximum increase at 75 mM NaCl. Hence, sage can be considered as moderately salt sensitive.     

Distribution of fatty acids in triacylglycerols and phospholipids from peas (Pisum sativum L.)

BACKGROUND: The fatty acid distribution of triacylglycerols (TAG) and major phospholipids (PL) obtained from four varieties of peas (Pisum sativum) was investigated. The total lipids extracted from the peas were separated by thin layer chromatography into seven fractions. RESULTS: The major lipid components were PL (52.2–61.3%) and TAG (31.2–40.3%), while hydrocarbons, steryl esters, free fatty acids and diacylglycerols (sn‐1,3 and sn‐1,2) were also present in minor proportions (5.6–9.2%). The main PL components isolated from the four varieties were phosphatidylcholine (42.3–49.2%), phosphatidylinositol (23.3–25.2%) and phosphatidylethanolamine (17.7–20.5%). Significant differences (P < 0.05) in fatty acid distribution were found for different pea varieties. Phosphatidylinositol was unique in that it had the highest saturated fatty acid content among the three PL. However, the principal characteristics of the fatty acid distribution in the TAG and three PL were evident among the four varieties: unsaturated fatty acids were predominantly located in the sn‐2 position while saturated fatty acids primarily occupied the sn‐1 or sn‐3 position in the oils of the peas. CONCLUSION: These results should be useful to both producers and consumers for the manufacture of pea foods in Japan. Copyright © 2007 Society of Chemical Industry     

Characterisation of fatty acids and bioactive compounds of kachnar (Bauhinia purpurea L.) seed oil

Information concerning the exact composition of kachnar (Bauhinia purpurea) seed oil is scare. In the present contribution, a combination of CC, GC, TLC and normal-phase HPLC were performed to analyse lipid classes, fatty acids and fat-soluble bioactives of kachnar seed oil. n-Hexane extract of kachnar oilseeds was found to be 17.5%. The amount of neutral lipids in the crude seed oil was the highest (ca. 99% of total lipids), followed by glycolipids and phospholipids, respectively. Linoleic, followed by palmitic, oleic and stearic, were the major fatty acids in the crude seed oil and its lipid classes. The ratio of unsaturated fatty acids to saturated fatty acid, was higher in neutral lipid classes than in the polar lipid fractions. The oil was characterised by a relatively high amount of phytosterols, wherein the sterol markers were β-sitosterol and stigmasterol. β-Tocopherol was the major tocopherol isomer with the rest being δ-tocopherol. In consideration of potential utilisation, detailed knowledge of the composition of kachnar (B. purpurea) seed oil is of major importance.     

微生物不饱和油脂研究

该文概述微生物油脂研究现状,列举不饱和脂肪酸功能、微生物不饱和油脂特点,包括产油微生物必备条件、生产原料、生成油脂的影响因素等;同时,介绍不饱和脂肪酸合成途径及制备工艺,并展望其应用前景。     

Effects of drying method on the extraction yields and quality of oils from quebec sea buckthorn (Hippophaë rhamnoides L.) seeds and pulp

The effects of air-drying and freeze-drying on the extraction yields and quality of oils from Quebec sea buckthorn (cv. Indian-summer) seeds and pulp were studied. Oil extractions were carried out using hexane. Air-dried (ADS) and freeze-dried (FDS) seeds, gave a similar extraction yields (∼12% w/w), whereas those of air-dried (ADP) and freeze-dried (FDP) pulps were significantly different (35.9 ± 0.8 vs. 17.1 ± 0.6% w/w). Fatty acid analysis revealed that α-linolenic (37.2–39.6%), linoleic (32.4–34.2%) and oleic (13.1%) acids were the main fatty acids in seed oils, while pulp oils were rich in palmitoleic (39.9%), palmitic (35.4%) and linoleic (10.6%) acids. Lipid fractionation of crude oils, obtained by solid phase extraction (SPE), yielded mainly neutral lipids (93.9–95.8%). The peroxide values of seed and pulp oils were ca. 1.8 meq/kg and between 3.0 and 5.4 meq/kg, respectively. The melting behavior of seed and pulp oils showed multiple endothermic transitions, as observed normally in vegetable oils.     

酶法改性微藻油脂制备功能性油脂的研究进展

多不饱和脂肪酸是一类对人体健康有益的生物活性物质,微藻油脂富含多不饱和脂肪酸,是天然可食用的潜在油源。利用微藻油脂开发制备型功能性油脂,替代动植物天然功能性油脂,不仅可提高天然功能性油脂的品质,解决供应问题,而且有望得到新的功能性油脂制品。对酶法制备功能性油脂的方法、常见微藻的油脂含量及其油脂的脂肪酸组成进行综述,并对酶法改性微藻油脂制备富含多不饱和脂肪酸的单酰甘油酯、结构三酰甘油酯、功能性磷脂等功能性油脂的研究进展进行了介绍。酶法改性微藻油脂制备功能性油脂是高值化利用微藻油脂的新途径。     

Compositional characteristics of muscle and visceral oil from steelhead trout and their oxidative stability

The quality of lipid from steelhead trout viscera, a byproduct of steelhead trout industry, was evaluated and compared with that of the muscle. Steelhead trout viscera had a higher lipid content than muscle and the visceral oil differed from muscle oil in its lipid class composition. Neutral lipids, mainly triacylglycerols (TAG), comprised the major lipid class in both muscle and visceral lipid. However, as expected, muscle contained a remarkably higher level of phospholipids (PL) than viscera, and the ratio of total neutral lipids to polar lipids was lower in muscle than in viscera. Visceral and muscle lipid had similar fatty acid compositions, with the concentration of muscle polyunsaturated fatty acids (PUFA) slightly higher than that of visceral PUFA. Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) were the major n-3 PUFA present in both muscle and visceral lipid; docosapentaenoic acid (DPA) was present at about 1.61–1.76%. With respect to minor components, muscle lipid had higher α-tocopherol and total carotenoids contents than visceral lipid. Oxidative stability of visceral and muscle lipid, as determined by conjugated dienes (CD) and thiobarbituric acid reactive substances (TBARS), showed that visceral lipid was more stable against oxidation than muscle lipid, probably due to their different lipid profiles. Besides, carotenoids, which were present more abundantly in muscle, might have acted as prooxidants and therefore, decreased the oxidative stability of muscle lipid. These results suggest that steelhead trout viscera may serve as a good source of lipid and could be utilized for production of omega-3 oils.     

Essential oils and fatty acids composition of Tunisian and Indian cumin (Cuminum cyminum L.) seeds: a comparative study

BACKGROUND: Cumin (Cuminum cyminum L.) seeds of two geographic origins, Tunisia (TCS) and India (ICS), were studied regarding their fatty acid and essential oil composition. RESULTS: Oil yields were 17.77 and 15.40% for TCS and ICS respectively. Petroselinic acid (C18:1n‐12) was the major fatty acid in both varieties, with a higher proportion being found in TCS (55.90% of total fatty acids (TFA)) than in ICS (41.42% TFA). Moreover, the most predominant fatty acids were palmitic, petroselenic and linoleic acids, accounting for more than 91% TFA in both varieties. The unsaturated fatty acid content was high: 70.95% TFA in TCS and 62.17% TFA in ICS. Essential oil yields differed significantly (P < 0.05) between the two varieties: 1.21 and 1.62% for ICS and TCS respectively. A total of 40 compounds were identified, 34 of which were present in both essential oils. The two varieties displayed different chemotypes: γ‐terpinene/1‐phenyl‐1,2‐ethanediol for TCS and cuminaldheyde/γ‐terpinene for ICS. CONCLUSION: The study revealed that the biochemical composition of cumin seeds is origin‐dependent and that cumin seeds are rich in an unusual fatty acid, petroselinic acid. Besides, cumin essential oil is a rich source of many compounds, including cuminaldehyde and γ‐terpinene. The overall results suggest the exploitation of cumin seeds as a low‐cost renewable source for industrial processing in the fields of cosmetics, perfumes and pharmaceuticals. Copyright © 2011 Society of Chemical Industry     

两种不同壁材结构脂微胶囊的氧化稳定性与体外消化特性比较

该研究选择两种配方（配方1：酪蛋白酸钠/麦芽糊精配方;配方2：乳清蛋白/乳糖配方）对结构脂进行包埋处理,测定其氧化稳定性与体外消化特性相关指标并进行比较分析。结果表明：在氧化稳定性方面,结构脂原油经氧化后其过氧化值（Peroxide Value,POV）、硫代巴比妥酸反应物（Thiobarbituric Acid Reactivesubstances,TBARS）值与酸价分别增加了55.199 meq/kg、4.532 mg/kg和0.280 mg/g,总单不饱和脂肪酸（Monounsaturated Fatty Acid,MUFA）与多不饱和脂肪酸（Polyunsaturated Fatty Acid,PUFA）的含量分别减少了9.621%和15.664%;配方1的POV值、TBARS值与酸价增加了16.438 meq/kg、1.348 mg/kg和0.124 mg/g,总MUFA与PUFA减少了5.630%和9.368%;配方2的POV值、TBARS值与酸价增加了13.255 meq/kg、1.176 mg/kg和0.127 mg/g,总MUFA与PUFA减少了5.163%和8.5...     

Detecting vegetable oil adulteration in hazelnut paste (Corylus avellana L.)

The possibilities of detecting hazelnut paste adulterated with refined and non-refined vegetable oils have been studied. Research was focussed mainly on peanut, high oleic-acid sunflower, corn and soybean oils which have a similar composition to hazelnut oil. The analytical procedures to detect fatty acid (FA), triacylglycerol (TAG) and tocopherol profiles as indicators of adulteration were determined. The better indicators experimentally determined were seven FA (palmitic, stearic, linoleic, linolenic, arachidonic, behenic and lignoceric acids) and different TAG with three unsaturated FA (the code letters used for FA are: P = C_16:0; S = C_18:0; O = C_18:1; L = C_18:2;; L_n = C_18:3) (LLL_n, LLL and OOO), two unsaturated FA (POL, PLL and SOO), and one unsaturated FA (PPL). As expected, when refined vegetable oils were added to hazelnut paste, the increment of stigmasta-3,5-diene allowed detection at levels of 2% oil added. Limits of detection were measured using standard and adulterated hazelnut with different amounts of non-refined vegetable oils added (5%, 10%, 20% and 30%). The distribution of tocopherols and tocotrienols is highly useful, except in the case of added sunflower oil. The differences between the experimental and theoretical values of the TAG with equivalent carbon number (ΔECN) of 42 does not improve the detection limit of hazelnut paste adulterated with peanut or sunflower oils. Similarly, tocopherols usually added to refined vegetable oils as an antioxidant were also determined.     

Total lipid content and fatty acid composition of the seeds of some Vicia L. species

The seed oils of eight Vicia species (Leguminosae) were investigated for their total lipid contents and fatty acid compositions. The seed lipid contents were found to be between 2.30 and 3.91%. The fatty acid compositions of these eight different species were determined by gas chromatography of the methyl esters of their fatty acids. The seed oils of Vicia species contain palmitic and stearic acids as the major component fatty acids, among the saturated acids, with a small amounts of myristic, pentadecanoic, arachidic and behenic acids. The major unsaturated fatty acids found in the seed oils were oleic, linoleic and linolenic acids.     

BIOCHEMICAL CHARACTERIZATION OF BORAGE (BORAGO OFFICINALIS L.) SEEDS

Gas chromatography–mass spectrometry analysis of seed Borago officinalis essential oil (EO) revealed the presence of 16 volatile components. β-Caryophyllene (26%) and p-cymene-8-ol (19.7%) represented the major components, while nonadecane (0.7%) and hexanol (0.7%) were the minor ones. The EO composition was characterized by higher abundance of oxygenated monoterpenes (27.7%), followed by sesquiterpenes (26%). Fatty acid composition showed the predominance of linoleic (35.4%), oleic (24.2%) and γ-linolenic (20.4%) acids. Polyphenols were analyzed by reversed-phase high-performance liquid chromatography after acid hydrolysis of phenolic acid esters. Six phenolic acids were identified in seed extract and rosmarinic acid was the predominant one with 1.65 mg/g dry matter weight equivalent to 33% of total phenolic acids.

PRACTICAL APPLICATIONS

Borage ( Borago officinalis L.) is of great interest because of its medicinal and nutritional properties. In fact, thanks to its characteristic composition in fatty acids, particularly high levels of gamma-linolenic acid in its seed oil, borage has gained importance. The potent consumers of this medicinal plant are hypertensive and hypercholesterolemic people. Borage consumption is also recommended for people suffering from rheumatism and eczema.
Unfortunately, the knowledge about antioxidative/antiradical properties of borage is very scanty. So, recently, an extensive investigation was focused on the antioxidant properties of borage extracts. These extracts showed excellent antioxidant properties and their effects were attributed to their phenolic constituents. These antioxidants can be concentrated, either as crude extracts or individual phenolic compounds, to be used in highly unsaturated oils such as marine oils. Furthermore, borage consumption has been reported as a possible gastric cancer protective factor.     

Effect of blending and lipase catalyzed interesterification reaction on the cholesterol lowering properties of palm oil with rice bran oil in rats

The effect of feeding blended and interesterified oils containing palm oil (PO) and rice bran oil (RBO) on serum and liver lipids was evaluated in rats. The PO and RBO were blended to contain saturated, monounsaturated and polyunsaturated fatty acids in the proportion of 1:1.5:1. The blended oil was subjected to transesterification reaction using immobilized lipase, lipozyme IM‐RM. Rats were fed a diet containing blended or interesterified oils for 8 weeks. Rats fed PO showed significantly higher levels of cholesterol in serum and liver as compared to those given RBO, blended oil of PO with RBO or interesterified oil. Rats fed blended oils showed a significant decrease in serum cholesterol by 51% compared to rats fed PO. Feeding interesterified oil to rats resulted in decrease in serum cholesterol by 56% compared to rats fed PO, which was 10% lower compared to that observed in rats given blended oil. The present study indicated that a combination of PO with RBO can significantly lower serum lipids in rats as compared to those given diet containing PO alone.     

不同压榨工艺下花生油风味成分的变化

该研究采用顶空固相微萃取-气相色谱-质谱联用仪（HS-SPME-GC-MS）及电子鼻对不同压榨工艺下花生油挥发性风味成分和脂肪酸组成进行分析。6种不同压榨工艺花生油中共检测到10类38种挥发性成分,其中包含19种风味成分。在热榨花生油中以呋喃类（63.43%~66.68%）、醛类（10.04%~5.47%）、酚类（8.83%~7.18%）为主要的挥发性成分,在冷榨花生油中以酯类（26.43%）、醛类（23.47%）、酸类（22.10%）为主要的挥发性成分。此外,热榨花生油检测出少部分吡嗪、吡啶、酮类关键风味成分,其在冷榨花生油中并没有检出。电子鼻结果基本与GC-MS一致,硫化物、芳香化合物、氮氧化合物和甲基类化合物对花生油整体风味贡献率较大,通过主成分分析和K-mean聚类分析结果显示6种花生油挥发性成分变化差异显著。6种花生油脂肪酸组成都以油酸、亚油酸、棕榈酸为主,含量可达到90%以上。然而通过对比不同温度下花生油脂肪酸组成发现随着压榨温度的升高,不饱和脂肪酸的氧化加速。综上,对比不同压榨工艺下花生油风味和营养成分的变化发现高温条件压榨下花生油的风味成分显著增加,花生油品质略有下降,利用电子鼻可快速区分不同压榨工艺花生油。