Decomposition products of glycidyl esters of fatty acids by heating.

In this study, decomposition products of glycidyl palmitate (GP) of fatty acids heated at high temperature such as deep frying were investigated. When GP and tripalmitin (TP) were heated at 180 and 200 °C, they were decreased with heating time. The weight of GP was less than that of TP, although both GP and TP were converted to polar compounds after heating. The decomposition rate of GP was higher than TP. Both GP and TP produced considerable amounts of hydrocarbons and aldehydes during heating. Aldehydes produced from GP and TP included saturated aldehydes with carbon chain length of 3-10, while hydrocarbons consisted of carbon chain length of 8-15. It was observed that major hydrocarbons produced from GP during heating were pentadecane. Moreover, the level of carbon dioxide (CO2) released from GP was higher than that of TP. It was suggested that fatty acids in GE might be susceptible to decarboxylation. From these results, GP might be quickly decomposed to hydrocarbons, aldehydes and CO2 besides polar compounds by heating, in comparison with TP.

Effects of Heat-Cooking with Edible Fats and Oils on the Levels of 3-Chloro-1, 2-Propanediol Fatty Acid Esters (3-MCPDEs), 2-Chloro-1, 3-Propanediol Fatty Acid Esters (2-MCPDEs) and Glycidyl Fatty Acid Esters (GEs) in Processed Foods.

This study investigated the effect of cooking on the levels of 3-chloro-1, 2-propanediol esters (3-MCPDEs), 2-chloro-1, 3-propanediol esters (2-MCPDEs) and glycidyl esters (GEs) in deep-fried rice cracker, fried potato, croquette, fish fillet, chicken fillet and cooking oils (rice bran oil and palm oil). The levels of 2-/3-MCPDE in rice cracker fried with rice bran oil and the used oil remained about the same, while the levels of GEs in them fell with frying time. The levels of 2-/3-MCPDEs in fried potato, croquette, fried fish and chicken cutlet fried with rice bran oil and palm oil respectively fell with frying time, while the level of GEs in them remained about the same. The levels of 2-/3-MCPDEs and GEs in fried rice cooked with rice bran oil were under the method limit of quantification. These results provide insights the cooking has no influence with the levels of 2-/3-MCPDEs and GEs in cooked foods.

Differences in the Compositions of Vitamin E Tocochromanol (Tocopherol and Tocotrienol) in Rice Bran Oils Produced in Japan and Other Countries.

In this study, we investigated the compositions of vitamin E tocochromanol [tocopherol (Toc) and tocotrienol (T3)] in crude and refined rice bran oil (RBO) produced in Japan and other countries, including Brazil, Thailand, and Vietnam, based on high-performance liquid chromatography analysis. All RBO analyzed contained α-, ß- and γ-Toc and α-, γ- and δ-T3. Japanese crude RBO, although not refined RBO, also contained ß-T3. Furthermore, total Toc contents in both Japanese crude and refined oils were found to be higher than those in the crude and refined RBO from other countries. Total T3 contents in Japanese crude RBO were similar to those in the crude RBO from Brazil and Vietnam. The α-Toc and α-T3 contents in Japanese crude and refined RBO were considerably higher than those in the crude and refined RBO produced in other countries, whereas in contrast, γ-Toc and γ-T3 contents in Japanese crude and refined RBO were lower. Consequently, the ratios of total α-Toc and α-T3 contents to total γ-Toc and γ-T3 contents in Japanese crude and refined RBO (1.75 and 1.91, respectively) were notably higher than those in the crude and refined RBO produced in other countries. Similarly, the ratios of total Toc to total T3 in Japanese crude and refined RBO were higher than those in the crude and refined RBO produced in other countries. These results accordingly indicate that the ratio of total α-Toc and α-T3 contents to γ-Toc and γ-T3 contents could be used as an effective index to discriminate between the RBO produced in Japan and that produced in other countries.

Effects of non-methylene-interrupted polyunsaturated fatty acid, sciadonic (all-cis-5,11,14-eicosatrienoic acid) on lipid metabolism in rats.

We investigated effects of the non-methylene-interrupted polyunsaturated fatty acid, sciadonic acid (all-cis-5,11,14-eicosatrienoic acid), on the lipid metabolism in rats, to identify the mechanism for the plasma and hepatic triacylglycerol-lowering effects of Japanese torreya (Torreya nucifera) seed oil. Sciadonic acid was isolated from torreya seed oil by the combination of urea-adduct with lipase-esterification. Sprague-Dawley (SD) male rats were fed with experimental diets containing 5% and 10% sciadonic acid based on corn oil for 2 weeks. The serum and liver triacylglycerol levels were lower in the rats fed with sciadonic acid. Considerable amounts of sciadonic acid were detected in the triacylglycerol and phospholipid in both the serum and liver of the rats fed with sciadonic acid. These observations demonstrate that sciadonic acid could modify the lipid metabolism in rats.

Lipid Characteristics of Camellia Seed Oil.

Camellia oleifera, C. japonica and C. sinensis are three representative crops of the genus Camellia. In this work, we systematically investigated the lipid characteristics of these seed oils collected from different regions. The results indicated significant differences in acid value (AV), peroxide value (PV), iodine value (IV), saponification value (SV) and relative density of the above-mentioned camellia seed oils (p < 0.05). The C. japonica seed oils showed the highest AV (1.7 mg/g), and the C. sinensis seed oils showed the highest PV (17.4 meq/kg). The C. japonica seed oils showed the lowest IV (79.9 g/100 g), SV (192.7 mg/g) and refractive index (1.4633) of all the oils, while the C. sinensis seed oils showed the lowest relative density (0.911 g/cm3). The major fatty acids in the camellia seed oils were palmitic acid (16:0), oleic acid (18:1) and linoleic acid (18:2); the oleic acid in C. oleifera and C. japonica seed oils accounted for more than 80% of the total fatty acids. The oleic acid levels in the C. oleifera and C. japonica oils were higher than those in the C. sinensis seed oils, while the linoleic acid levels in the former were lower than those in the latter one. Differences also exist in the triacylglycerol (TAG) composition, although the most abundant TAG molecular species in the camellia seed oils was trioleoylglycerol (OOO). Seven sterol species, squalene and α-tocopherol were detected in the camellia seed oils, however, the contents of tocopherol and unsaponifiable molecules in the C. oleifera and C. japonica seed oils were significantly lower than those in the C. sinensis seed oil. These results demonstrated that the varieties of Camellia affected the seed oil lipid characteristics.

Effects of Cultivars and Geography in China on the Lipid Characteristics of Camellia oleifera Seeds.

New cultivars of Camellia oleifera have been developed and planted in southern China. However, lipid characteristics of their seed oils were still unclear. In this study, nine C. oleifera fruits were collected from different cultivars in different planting regions, and the lipid characteristics, such as oil content, fatty acid composition, triacylglycerol composition, tocopherol content and sterol composition were investigated for their seed oils. The oil content in Yuekexia-2 was the lowest (11.6%), while those in other cultivars ranged from 22.3% to 29.6%. The major fatty acids of C. oleifera seed oils (COSOs) were palmitic acid (16:0, 8.4-11.5%), oleic acid (18:1, 76.3-80.5%), and linoleic acid (18:2, 7.9-12.2%), respectively. Trioleoylglycerol (OOO) was the most abundant triacylglycerol specie (more than 50%) in the COSOs. COSOs contained 21.2-36.4 mg/100 g of α-tocopherol. Seven sterols and squalene were found in all COSOs, while the COSOs showed significant differences in their contents of unsaponifiable matters. The planting region and the cultivar type significantly affected some of the lipid characteristics with the C. oleifera seeds.

Determination of γ-Oryzanol in Refined Rice Bran Oil by Nuclear Magnetic Resonance Method.

γ-Oryzanol contained as a minor component in rice bran oil (RBO) is a group of phytosterol ferulates. The existence of γ-oryzanol in rice bran oil is very interesting because of the special biological functions. The methods to determine γ-oryzanol in crude RBO include the absorptiometry, thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). However, those methods need much solvent and long operating time. Moreover, some of those methods are not able to apply to refined RBO because of the low sensitivity. We have developed the method to determine γ-oryzanol in refined RBO using proton nuclear magnetic resonance (1H-NMR). Refined RBO had a specific chemical shift due to the methoxy group of ferulate in γ-oryzanol at 3.9 ppm on the 1H-NMR spectrum. The intensity of the chemical shift due to the methoxy group of ferulate was consistent with the amounts of γ-oryzanol in refined RBO. This NMR method was able to quickly and easily determine γ-oryzanol in refined RBO.

Seeds of Centranthus ruber and Valeriana officinalis Contain Conjugated Linolenic Acids with Reported Antitumor Effects.

Conjugated linolenic acids (CLNs) are naturally occurring fatty acids that are believed to have anticancer properties. In this study, we examined various plant seeds from herbs to discover seed oils containing CLNs. The ultraviolet spectra of total lipids from these seeds were measured. An absorption maximum around 270 nm was observed in seed oils belonging to the Valerianaceae family (Centranthus ruber and Valeriana officinalis). When the fatty acid compositions of these seed oils were measured, CLNs were detected. By silica column chromatography, neutral lipids (NLs), glycolipids, and phospholipids were eluted from seed oils of C. ruber and V. officinalis. Then, fatty acid compositions of these fractions were measured. This revealed that most of the CLNs in these seed oils existed in the NL fraction. When the NL fractions of these seed oils were reacted with lipase, CLNs showed good sensitivity to lipase hydrolysis. This suggested that the CLNs in the seed oils of C. ruber and V. officinalis existed predominantly at the sn-1,3 position of triacylglycerol and less at the sn-2 position. These results suggested that the CLNs from the seed oils of C. ruber and V. officinalis could easily be taken up by cancer cells as free fatty acids and had good potential as antitumor substances.

Long-term supplementation of docosahexaenoic acid-rich, eicosapentaenoic acid-free microalgal oil in n-3 fatty acid-deficient rat pups.

Rat pups deficient in n-3 fatty acids received an oral administration of docosahexaenoic acid (DHA)-rich, eicosapentaenoic acid (EPA)-free microalgal oil (DMO) or fish oil (FO). DMO administration almost restored liver EPA to the level of the control diet-fed dam's pups, but FO administration did not. This suggests that EPA could be recovered in the liver, even though EPA-free DMO was supplemented.

Analytical Methods to Evaluate the Quality of Edible Fats and Oils: The JOCS Standard Methods for Analysis of Fats, Oils and Related Materials (2013) and Advanced Methods.

Edible fats and oils are among the basic components of the human diet, along with carbohydrates and proteins, and they are the source of high energy and essential fatty acids such as linoleic and linolenic acids. Edible fats and oils are used in for pan- and deep-frying, and in salad dressing, mayonnaise and processed foods such as chocolates and cream. The physical and chemical properties of edible fats and oils can affect the quality of oil foods and hence must be evaluated in detail. The physical characteristics of edible fats and oils include color, specific gravity, refractive index, melting point, congeal point, smoke point, flash point, fire point, and viscosity, while the chemical characteristics include acid value, saponification value, iodine value, fatty acid composition, trans isomers, triacylglycerol composition, unsaponifiable matters (sterols, tocopherols) and minor components (phospholipids, chlorophyll pigments, glycidyl fatty acid esters). Peroxide value, p-anisidine value, carbonyl value, polar compounds and polymerized triacylglycerols are indexes of the deterioration of edible fats and oils. This review describes the analytical methods to evaluate the quality of edible fats and oils, especially the Standard Methods for Analysis of Fats, Oils and Related Materials edited by Japan Oil Chemists' Society (the JOCS standard methods) and advanced methods.

Autoxidation of Fish Oil Blended with Rice Bran Oil.

Effects of rice bran oil on the oxidative and flavor stability of fish oil were investigated by the gas liquid chromatography-head space method. When fish oil blending with different ratio of rice bran oils was oxidized at room temperature in the dark, volatile compounds produced during autoxidation was measured by gas liquid chromatography. The amounts of volatile compounds were decreased with increased the ratio of blended rice bran oil as well as peroxide value. The level of propanal and acrolein which gave unpleasant flavor was also decreased with increased the ratio of blended rice bran oil. Especially, the level of propanal and acrolein and peroxide value were remarkably decreased when blending more than 75% of rice bran oil. Blending of rice bran oil improved the oxidative and flavor stabilities of fish oil.

Effects of Japanese torreya (Torreya nucifera) seed oil on lipid metabolism in rats.

OBJECTIVE: We investigated effects of Japanese torreya (Torreya nucifera) seed oil containing non-methylene-interrupted polyunsaturated fatty acid of all-cis-5,11,14-eicosatrienoic acid (sciadonic acid) on rat lipid metabolism. METHODS: Male Sprague-Dawley rats were fed the experimental diets based on AIN-93 containing 10% corn, soybean, or torreya oil for 4 wk. Blood and tissues were recovered from each rat, and concentrations of triacylglycerol, cholesterol, and phospholipid in plasma and liver were determined by enzymatic assays. Moreover, fatty acid composition was analyzed for triacylglycerol, cholesterol ester, and phospholipid isolated from plasma and liver lipids by gas liquid chromatography. RESULTS: Plasma triacylglycerol level in rats fed torreya oil was lower than that in rats fed corn or soybean oil, although there were no significant differences in plasma cholesterol and phospholipid levels in all rats. Liver triacylglycerol level was also lower in rats fed torreya oil, whereas liver cholesterol and phospholipid levers were same for all rats. omega-3 Polyunsaturated fatty acids such as 22:6 (omega-3) were lower in plasma and liver lipids of torreya and corn oil groups, whereas omega-6 polyunsaturated fatty acids such as 22:4 (omega-6) and 22:5 (omega-6) were higher. Considerable amounts of sciadonic acid were detected in cholesterol ester, triacylglycerol, and phospholipid in plasma and liver of rats fed torreya oil. CONCLUSION: These observations suggest that torreya seed oil can modify lipid metabolism, resulting in lower triacylglycerol levels in plasma and liver of rats.

Trans fatty acids promote the growth of some Lactobacillus strains.

Five Lactobacillus strains (2 L. gasseri, 2 L. plantarum and 1 L. reuteri) were cultured in modified MRS medium containing fatty acids (FAs) instead of Tween 80 for 24 h at 37 degrees C, to learn the effect of saturated and unsaturated FAs on the Lactobacillus growth. Free FAs included palmitic (16:0), palmitoleic (c9-16:1), stearic (18:0), oleic (c9-18:1), elaidic (t9-18:1), cis-vaccenic (c11-18:1), vaccenic (t11-18:1), linoleic (c9, c12-18:2), conjugated linoleic (c9, t11- and t10, c12-18:2), alpha-linolenic (c9, c12, c15-18:3), alpha-eleostearic (c9, t11, t13-18:3), eicosapentaenoic (20:5), and docosahexaenoic (22:6) acids. Among free FAs, oleic acid stimulated the growth of all Lactobacillus strains, whereas palmitoleic acid had almost no affect on the Lactobacillus growth. Saturated FAs such as stearic and palmitic acids inhibited or did not affect the Lactobacillus growth. Polyunsaturated FAs such as alpha-linolenic, eicosapentaenoic and docosahexaenoic acids strongly inhibited the Lactobacillus growth at 7.6 x 10(-4) m. Octadecenoic acids such as oleic, elaidic, cis-vaccenic and vaccenic acids remarkably promoted the growth of L. gasseri, regardless of the different double bond positions and configurations. When oleic or cis-vaccenic acid was incubated with L. gasseri, the FAs was transformed to cyclopropane FAs (methyleneoctadecanoic acids) after incorporation into the cells. On the other hand, trans FAs such as elaidic and vaccenic acids incorporated into the cells were not converted to another FAs. Conjugated linoleic and alpha-eleostearic acids having a trans double bond promoted the Lactobacillus growth. The growth of L. gasseri was also stimulated by trans-rich free FAs from hydrogenated canola and fish oils. These results showed that octadecenoic acid and trans FAs had strong promotion activities for the Lactobacillus growth due to their incorporation into membrane lipids.

Oxidative degradation of bisphenol a by crude enzyme prepared from potato.

When crude enzymes prepared from some vegetables and fruits were incubated with bisphenol A (2,2-bis(4-hydroxyphenyl)propane, BPA) at 37 degrees C, BPA was oxidized by crude enzymes from potato, eggplant, and lettuce. The crude enzyme prepared from potato (Solanum tuberosum) had the strongest oxidative activity for BPA. Its optimal temperature and pH were 40-45 degrees C and 8.0, respectively. More than 95% of BPA was oxidized after the incubation with potato enzyme for 60 min. BPA gave two oxidation products besides insoluble compounds during the oxidation by potato enzyme. The oxidation products were identified to be 4[1-(4-hydroxyphenyl)-1-methyl-ethyl]-benzene-1,2-diol and 4[1-(4-hydroxyphenyl)-1-methyl-ethyl]-benzene-1,3-diol. Enzymatically oxidized BPA lost the estrogen-like activity to enhance the growth of human breast cancer (MCF-7) cells.

Occurrence of a novel cis,cis,cis-octadeca-3,9,12-trienoic (Z,Z,Z-octadeca-3,9,12-trienoic) acid in Chrysanthemum (tanacetum) zawadskii herb. (Compositae) seed oil.

A new octadecatrienoic acid (6.9%), found as a component of Chrysanthemum zawadskii Herb. (Asteraceae) seed oil, was shown to be the hitherto unknown cis,cis,cis-octadeca-3,9,12-trienoic acid. The oil also contained 8.6% of crepenynic acid in addition to the other common FA. The structures of the new unusual FA and other FA were confirmed by chromatographic (TLC, GC), spectroscopic (IR, UV, and NMR), and MS methods by using different chemical derivatizations (preparation of methyl ester, pyrrolidide, picolinyl esters, and dimethyloxazoline derivatives).

Oxidative degradation of alkylphenols by horseradish peroxidase.

Alkylphenols such as bisphenol A (2,2-bis(4-hydroxyphenyl)propane; BPA), p-nonylphenol (p-NP), and p-octylphenol (p-OP) that are known as endocrine disrupters were oxidized by horseradish (Armoracia rusticana) peroxidase (HRP) with H2O2. The optimal pHs for BPA, p-NP, and p-OP were 8.0, 7.0, and 5.0, respectively. The optimal temperature for BPA was 20 degrees C. Although BPA was rapidly degraded by HRP, its degradation depended on the concentration of HRP. Most of the oxidation products of BPA were polymers, although some 4-isopropenylphenol was produced. When male Japanese medaka (Oryzias latipes) were exposed to BPA, vitellogenin in the blood increased. However, no increased vitellogenin was observed in medaka exposed to HRP-oxidized BPA. The enzymatic oxidation of BPA using HRP was able to eliminate its estrogen-like activity.

Effect of dietary tung oil on the growth and lipid metabolism of laying hens.

The influence of dietary tung oil, containing a high level of alpha-eleostearic acid (cis-9, trans-11, trans-13-octadecatrienoic acid, EA) on growth, egg production, and lipid and fatty acid compositions in tissues and egg yolks of laying hens was studied in White Leghorn hens. Forty-week-old hens were divided into three groups of eight birds each and fed diets containing 0, 0.5, or 1.0% tung oil for 6 wk. The average body weight, feed consumption, rate of egg production, and weights of eggs and yolks were not affected. The weight of adipose tissue was remarkably small in hens fed tung oil, whereas the yolk lipid content did not change. Triglyceride level in heart and adipose tissue decreased in hens fed tung oil, and the level of linolenic acid (C18:3) in all tissues was decreased. Alpha-EA was not almost deposited in the tissues and egg yolk of hens fed tung oil, but conjugated linoleic acid (CLA) was detected in all tissues and egg yolks. The level of CLA in the tissues was significantly higher with increased dietary tung oil. The order of CLA level in tissue lipids was adipose tissue>liver>heart>breast muscle. Especially, the level of CLA in the lipids of adipose tissue and egg yolks of hens fed 1.0% tung oil was 2.0% of the total fatty acid. These results supposed that dietary tung oil affected the lipid metabolism of laying hens and could modify the lipid and fatty acid composition in tissues and eggs.

Occurrence of conjugated polyenoic fatty acids in seaweeds from the Indian Ocean.

Three species of red marine macro algae (Rhodophyta) from the Indian Ocean were analysed for the occurrence of conjugated polyenes. The composition of different lipid classes in these seaweeds along with their fatty acid composition has also been reported. Analysis of lipid classes of these seaweeds revealed that both Acanthophora spicifera (Ceramiales, Rhodophyta) and two species of Gracilaria, viz. G. edulis and G. folifera (Gracilariales, Rhodophyta) were rich in glycolipids followed by neutral- and phospholipids. The fatty acid composition of these seaweeds revealed C16:0 as the predominant fatty acid in all three species. However, A. spicifera had significantly higher amounts of eicosapentaenoic acid (EPA) and arachidonic acid (AA) as compared to negligible amount of these fatty acids in both species of Gracilaria. The red seaweed Acanthophora spicifera contained conjugated eicosapentaenoic acid (CEPA) and conjugated arachidonic acid (CAA) in all lipid classes except glycolipids.

Antioxidant effects of pH-regulating agents on the thermal deterioration of vegetable oils.

pH-Regulating agents, such as sodium tartrate, disodium succinate, and trisodium citrate, were investigated for their antioxidant activities during the thermal deterioration of vegetable oils. Refined rapeseed and rice bran oils, supplemented with pH-regulating agents and α-tocopherol (0.1%) were heated at 180℃. After heating, acid values (AVs), carbonyl values (CVs), polar material contents, and color (absorbance at 420 nm) of each sample were measured. All pH-regulating agents gave rise to reduced AVs, CVs, and polar material contents of vegetable oils during heating relative to samples not containing a pHregulating agent. Rapeseed and rice bran oils supplemented with sodium tartrate showed the lowest AVs, CVs, polar material contents and absorbances at 420 nm after heating. Sodium tartrate not only retarded the hydrolysis, thermal oxidation, polymerization, and coloration of both oils while heating at high temperatures, but it also showed antioxidant activity at the supplementation level of 0.01%. The antioxidant activity of sodium tartrate was higher than that of α-tocopherol during the deterioration of vegetable oils. Sodium tartrate was particularly effective retarding hydrolysis while heating at high temperatures, resulting in increase of AVs of vegetable oils. Sodium tartrate is therefore expected to be an effective antioxidant for the thermal deterioration of fats and oils during deep-fat frying.

Rapid determination of saponification value and polymer content of vegetable and fish oils by terahertz spectroscopy.

A rapid method for determining the saponification value (SV) and polymer content of vegetable and fish oils using the terahertz (THz) spectroscopy was developed. When the THz absorption spectra for vegetable and fish oils were measured in the range of 20 to 400 cm⁻¹, two peaks were seen at 77 and 328 cm⁻¹. The level of absorbance at 77 cm⁻¹ correlated well with the SV. When the THz absorption spectra of thermally treated high-oleic safflower oils were measured, the absorbance increased with heating time. The polymer content in thermally treated oil correlated with the absorbance at 77 cm⁻¹. These results demonstrate that the THz spectrometry is a suitable non-destructive technique for the rapid determination of the SV and polymer content of vegetable and fish oils.