Highly sensitive method for the quantification of trans-linolenic acid isomers in trilinolenin of edible oils using an ionic liquid capillary column.

BACKGROUND: The polarities of linolenic acid isomers are very similar, and only a few studies to date have attempted to separate α-linolenic acid (ALA) isomers completely. The aim of this study was to fill this gap by developing and validating an accurate method for the analysis of ALA isomers in trilinolenin at 200, 220 and 240 °C using a gas chromatograph-flame ionization detector equipped with an SLB-IL111 capillary column. RESULTS: Results showed that eight ALA isomer standards were separated effectively using these optimized gas chromatographic conditions. The coefficient of determination was r2 > 0.9994 in the linear range of each ALA isomer. The obtained limits of detection and limits of quantification of the ALA isomers were 0.02-0.08 ppm and 0.05-0.22 ppm, respectively. A high degree of reproducibility and percent recoveries between 96.2% and 106.5%, with coefficients of variation ranging from 0.82% to 0.97%, were achieved. CONCLUSION: The developed method has been successfully applied to the analysis of ALA isomers in heated pure trilinolenin as well as to trilinolenin in various edible oils, and the TALA isomerization pathways in heated trilinolenin were verified. © 2017 Society of Chemical Industry.

Reaction pathway mechanism of thermally induced isomerization of 9,12-linoleic acid triacylglycerol.

BACKGROUND: To clarify the formation mechanism of trans linoleic acid isomers in edible oils during the heating process, trilinolein and trilinoelaidin, as representative oils, were placed in glass ampoules and sealed before heating at 180, 240 and 320 °C. The glass ampoules were removed at regular time intervals, and the contents were analyzed by infrared spectroscopy. The samples were then subjected to derivatization into their methyl esters for gas chromatographic analysis. RESULTS: Analysis results show that 9c,12c and 9t,12t fatty acids from trilinolein and trilinoelaidin molecules undergo chemical bond rotation, migration and degradation, leading to the formation of non-conjugated linoleic acids (NLAs), conjugated linoleic acids (CLAs) and aldehydes. The formation rate of isomers from the 9c,12c fatty acid is higher than that of the 9t,12t fatty acid. The production of aldehydes increases with heating temperature and time. The isomerization pathways involved in the formation of NLAs and CLAs during heating are clearly presented. CONCLUSION: These findings suggest possible pathways of NFA and CFA formation from heated trilinolein and trilinoelaidin, complement the mechanistic studies previously published in the literature, and provide a theoretical basis for future control of the quality and safety of fats and oils. © 2016 Society of Chemical Industry.

Investigating the amount of TFAs, CLAs and ω6/ω3 of various brands of corn oil heated at different time-temperature treatments.

A qualitative and quantitative analysis of trans fatty acids (TFAs), conjugated linoleic acids (CLAs) and linoleic acid/α-linolenic acid (ω6/ω3) in eleven different brands of fresh and heated corn oil was investigated. Corn oil was subjected to thermal treatment at 180, 210 and 230 °C for 4, 8 and 12 h. The kinds of fatty acids were almost the same in all eleven brands of corn oil, but there were differences in the quantities of TFAs, CLAs and ω6/ω3 among the brands. The formation of TFAs in different brands of corn oil increased slowly at 180 °C and rapidly at 230 °C with the maximum increase of 28 and 374%, respectively. The formation of CLAs also increased during the heating with the amount of 0.00-0.32 g/100 g in fresh corn oil and 0.71-1.12 g/100 g in corn oil heated at 230 °C for 12 h. The value of ω6/ω3 was high in corn oil and increased with heating temperature and time. The largest rise of ω6/ω3 can reach upwards of 239:1. The results showed that temperature control was essential for maintaining the quality and nutritional value of corn oil.

The impact of technical cashew nut shell liquid on thermally-induced trans isomers in edible oils.

The effects of technical cashew nut shell liquid (TCNSL) on the trans isomerization of edible oils during heating are investigated. Edible oils were subjected to thermal treatment at various heating times and temperatures. Our results show that the addition of TCNSL to edible oils at the appropriate concentration during heating suppresses trans fatty acid formation and induces formation of conjugated linoleic acid (CLA) isomers. A concentration of 0.2 % TCNSL demonstrates the best ability to inhibit formation of trans-oleic acid, trans-linoleic acid, and trans-linolenic acid isomers as well as increase the formation of 9 t,11 t-CLA and 10 t,12 t-CLA isomers. Our analysis indicates that the presence of 0.2 % TCNSL in corn oil does not significantly reduce the acid value, but may significantly lower the peroxide value. TCNSL is also observed to have better function compared to Vitamin E (VE) and tertiary butylhydroquinone (TBHQ), indicating that it may be considered an effective additive in edible oils.

[Analysis of Spirulina powder by Fourier transform infrared spectroscopy and calculation of protein content].

Spirulina, Spirulina powder and dextrin standard were analyzed and identified by Infrared (IR) spectroscopy. The main components, protein (1 657 and 1 537 cm(-1)) and carbohydrate (1 069 and 1054 cm(-1)), had distinct fingerprint characteristics of IR spectra. By comparing the IR spectra of Spirulina, Spirulina powder and dextrin standard, the dominant nutrition in Spirulina powder was identified as protein and carbohydrate. The dominant accessory added in Spirulina powder was dextrin. Comparing the IR spectra of Spirulina powder from 28 different factories and figuring out the correlation provides the information about the amount of accessory. A standard curve of the ratio of absorption peak intensities to protein content was constructed to accurately determine the amount of protein in Spirulina powder.

New research development on trans fatty acids in food: Biological effects, analytical methods, formation mechanism, and mitigating measures.

The trans fatty acids (TFAs) in food are mainly generated from the ruminant animals (meat and milk) and processed oil or oil products. Excessive intake of TFAs (>1% of total energy intake) caused more than 500,000 deaths from coronary heart disease and increased heart disease risk by 21% and mortality by 28% around the world annually, which will be eliminated in industrially-produced trans fat from the global food supply by 2023. Herein, we aim to provide a comprehensive overview of the biological effects, analytical methods, formation and mitigation measures of TFAs in food. Especially, the research progress on the rapid, easy-to-use, and newly validated analytical methods, new formation mechanism, kinetics, possible mitigation mechanism, and new or improved mitigation measures are highlighted. We also offer perspectives on the challenges, opportunities, and new directions for future development, which will contribute to the advances in TFAs research.

A novel biosensor regulated by the rotator of F0F1-ATPase to detect deoxynivalenol rapidly.

A novel biosensor (immuno-rotary biosensor) was developed by conjugating deoxynivalenol (DON) monoclonal antibodies with the "rotator" ε-subunit of F(0)F(1)-ATPase within chromatophores with an ε-subunit monoclonal antibody-biotin-avidin-biotin linker to capture DON residues. The conjugation conditions were then optimized. The capture of DON was based on the antibody-antigen reaction and it is indicated by the change in ATP synthetic activity of F(0)F(1)-ATPase, which is measured via chemiluminescence using the luciferin-luciferase system with a computerized microplate luminometer analyzer. 10(-7)mg/ml of DON can be detected. The whole detection process requires only about 20min. This method has promising applications in the detection of small molecular compounds because of its rapidity, simplicity, and sensitivity.

Temporal changes of radiocesium in irrigated paddy fields and its accumulation in rice plants in Fukushima.

About half of the total paddy field area, which is the dominant agricultural land in Fukushima Prefecture, was contaminated by radiocesium released by the Fukushima Daiichi Nuclear Power Plant accident. In this study, we investigated the temporal changes of radiocesium in soil, irrigation water, and rice plant in two adjacent rice paddies, with and without surface-soil-removal, in Fukushima Prefecture for over three years (2012-2014) after the nuclear accident. Our results showed that radiocesium migrated into 24-28 cm soil layers and that the activity concentration of radiocesium in paddy soils showed a significant reduction in 2014. The newly added radiocesium to paddies through irrigation water contributed only a maximum value of 0.15% and 0.75% of the total amount present in control and decontaminated paddies, respectively, throughout the study period. The radiocesium activity concentration in suspended sediment in irrigation water exponentially decreased, and the effective half-lives (Teff) for (137)Cs and (134)Cs were 1.3 and 0.9 years, respectively. Additionally, the average suspended sediment concentration in irrigation water increased between 2012 and 2014, suggesting that enhanced soil erosion had occurred in the surrounding environment. Radiocesium accumulation in rice plant also decreased with time in both paddies. However, the concentration ratio of radiocesium for rice plant in the decontaminated paddy increased compared with control paddy, despite approximately 96% of fallout radiocesium removed in paddy soil. Further analysis is required to clarify the reasons of high concentration ratio of radiocesium for rice plant in the decontaminated paddy.

Assessment of radiological risk for marine biota and human consumers of seafood in the coast of Qingdao, China.

This paper reports the levels of (226)Ra, (232)Th, (40)K and (137)Cs in the edible parts of 11 different marine species collected from the Qingdao coast of China. The activities of (226)Ra, (232)Th and (40)K ranged from 0.08±0.03 to 1.65±0.60 Bq kg(-1) w.w., 0.09±0.02 to 1.44±0.10 Bq kg(-1) w.w., 26.89±1.25 to 219.25±5.61 Bq kg(-1) w.w., respectively. Artificial (137)Cs was undetectable or close to the detection limit in the biota sampled. To link radioactivity to possible impact on health, we calculated radiation doses to both the marine biota and human beings. We showed that doses in all cases were dominated by naturally occurring (40)K and that (137)Cs doses were negligible compared with (40)K-derived doses. The total doses to marine biota ranged between 16.55 and 62.41 nGy h(-1) among different biota species, which were below the benchmark level of aquatic organism. The committed effective dose to humans through seafood consumption varied from 10.55 to 36.17 µSv y(-1), and the associated lifetime cancer risks ranged from 5.93E-05 to 9.49E-05 for different age and gender groups. Both the dose and cancer risk to humans were at the acceptable range. Despite the significant amount of radionuclides released as a result of the Fukushima accident, their impact on the seafood in Qingdao coast appears to be negligible based on our measurements of concentrations of radionuclide activity and internal dose estimates.

Development of a novel biosensor based on F(0)F(1)-ATPase for the detection of 2-dodecylcyclobutanone in irradiated beef.

A novel biosensor regulated by the rotator of F0F1-ATPase was developed to analyze 2-dodecylcyclobutanone (2-DCB) to detect γ-ray irradiated beef rapidly. The biosensor was assembled by conjugating 2-DCB monoclonal antibodies with the "rotator" ε-subunit of F0F1-ATPase within chromatophores through an ε-subunit monoclonal antibody-biotin-avidin-biotin linker. The limit of detection (LOD) of 2-DCB was approximately 10(-8) µg/mL. The recovery ratio of 2-DCB from ground beef patties ranged from 75.1% to 116.4%. The intra-assay and inter-assay coefficients of variation were both <15.0%. The proposed method was validated by gas chromatography-mass spectrometry with high correlation. The biosensor was used to detect 2-DCB in ground beef patties with different fat contents (10%, 20%, and 30%) irradiated at 0.5, 1.0, 3.0, 5.0, and 7.0 kGy. The 2-DCB concentration linearly increased with the radiation dose in all the beef samples. 2-DCB concentration increased with fat levels in the three samples.

Synthesis of two ß-cyclodextrin derivatives containing a vinyl group.

ß-CD maleate (CDM) and ß-CD itaconate (CDI) were prepared by esterification of ß-cyclodextrin (ß-CD) with maleic acid and itaconic acid using phosphate as a catalyst in a semi-dry process. The esterification of ß-CD was carried out using [Itaconic acid ] or [Maleic acid ] 4 mol/mol of CD; M/L ratio 1:0.6; temperature 110 °C; [4-methoxyphenol] 2.5% amount of acid; reaction time 3.5h. The esterification rates of CDM and CDI are 70.38% and 21.02%, respectively. We found that CDM and CDI were both monoesters. Here, we also established a new evaluation method for the rate of esterification.

Complexation of synthetic CDM-AM copolymer with natamycin and carbendazim to improve solubility and fungicidal activity.

The ß-cyclodextrin-acrylamide (CDM-AM) copolymer was prepared from acrylamide and ß-CD maleate (CDM) using K2S2O8 as initiator. The effects of the CDM-AM copolymer on the solubility and fungicidal activity of natamycin (NM) and carbendazim (MBC) were investigated. The stability constant of NM·CDM-AM and MBC·CDM-AM complexes at 303 K were of 10,725.45 M(-1) and 3000.89 M(-1), respectively. The complexes were characterized using phase solubility diagrams, NMR spectra and FT-IR spectra. The analysis of the biological activities of these two complexes indicated that they possessed enhancing fungicidal activities compared to NM and MBC alone.

Impact of additives on thermally-induced trans isomers in 9c,12c linoleic acid triacylglycerol.

Trilinolein, with or without additives, was placed in glass ampoules and subjected to thermal treatment at 180 °C or 240 °C for 8h. Thermal treatment of trilinolein at 180 °C and 240 °C produced twice the amount of trans nonconjugated linoleic acids (NLAs) compared to conjugated linoleic acids (CLAs), and nitrogen stream reduced the amount of both trans NLA and CLA products. The presence of additives resulted in the suppression or induction of trans NLAs and CLAs, depending on the type of additive, the concentration of the additive, and the heating temperature. Our analysis indicates that TBHQ is an effective additive for reducing trans NLA formation and inducing trans CLA formation in frying oil. Glutathione and L-cysteine at 0.1% may also be used as additives for frying oil. At suitable concentrations, Fe(3+) and Al(3+) ions derived from oils can reduce trans NLAs and induce trans CLAs during frying.

Thermally induced isomerization of linoleic acid in soybean oil.

The molecular mechanisms of the thermally induced cis/trans isomerization of the non-conjugated linoleic acids (C18:2) were investigated in a combined experimental and computational study of C18:2 isomers. C18:2 isomers in soybean oil heated at two temperatures (180 and 220 ° C) were analyzed by GC method. C18:2-9c, 12t and C18:2-9t,12c were both the main trans isomers in heated soybean oil. Two alternative isomerization schemes via the proton transfer paths were developed. The geometries in ground states, transition states, and intermediates were optimised using the density functional theory (DFT) at B3LYP/6-31G* level. The formation of C18:2-9t, 12t had two barriers; the first of which was the formation of C18:2-9c, 12t or C18:2-9t, 12c. Zero-point energy corrections of each isomer was calculated at B3LYP/6-311++G** level. The intrinsic reaction coordinates (IRCs) were obtained to examine the transition states and intermediates. The activation energy differences between the cis and trans isomers of C18:2 possibly contributed to the distribution of the final ratio of the isomers. The DFT calculations indicated that the obtained experiment data was well explained by the isomerization mechanism developed.

Development of a competitive indirect enzyme-linked immunosorbent assay based on monoclonal antibodies for the detection of 2-dodecylcyclobutanone in irradiated beef.

A highly sensitive and specific competitive indirect enzyme-linked immunosorbent assay (ciELISA) based on monoclonal antibodies was developed for the detection of 2-dodecylcyclobutanone (2-DCB), a chemical marker for irradiated lipid-containing foods. 2-Oxocyclobutane undecanoic acid was used as an alternative to 2-DCB and conjugated to BSA and OVA via a conventional carbodiimide condensation reaction to prepare the immunogen and the coating antigen for 2-DCB. The monoclonal antibody against 2-DCB was obtained using the hybridoma technique, with a high specificity and low cross-reactivity for 2-tetradecylcyclobutanone (2-TCB; <8%) and other structurally related compounds (<0.1%). The ciELISA method was applicable at optimal experimental conditions of 0.001-100 µg/mL 2-DCB in a buffer solution, with an IC50 value of 0.25 µg/mL and a limit of detection (defined as the IC20) of approximately 0.004 µg/mL. The recovery efficiency of 2-DCB from ground beef patties ranged from 84.4 to 109.8%. The intra-assay and interassay coefficients of variation were <10.0 and <12.0%, respectively. The proposed method was validated by gas chromatography-mass spectrometry with high correlation. The same method was used to detect 2-DCB in ground beef patties irradiated at 0.5, 1.0, 3.0, 5.0, and 7.0 kGy; the 2-DCB concentration linearly increased with the radiation dose.

Determination of thermally induced trans-fatty acids in soybean oil by attenuated total reflectance fourier transform infrared spectroscopy and gas chromatography analysis.

The intake of edible oil containing trans-fatty acids has deleterious effects mainly on the cardiovascular system. Thermal processes such as refining and frying cause the formation of trans-fatty acids in edible oil. This study was conducted to investigate the possible formation of trans-fatty acids because of the heat treatment of soybean oil. The types of trans-fatty acids in heated soybean oil are determined by attenuated total reflectance Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry methods. The effects of the heating temperature on the trans-fatty acids in soybean oil were evaluated using gas chromatography flame ionization detection analysis. Results show that heat treatment at 240 °C causes the formation of trans-fatty acids in soybean oil and the amount of trans-fatty acids increases with heating time. The only peak observed at 966 cm(-1) of the samples indicates the formation of nonconjugated trans isomers in the heated soybean oil. The major types of trans-fatty acids formed were trans-polyunsaturated fatty acids. Significant increases (P < 0.05) in the amounts of two trans-linoleic acids (C18:2-9c,12t and C18:2-9t,12c) and four trans-linolenic acids (C18:3-9c,12c,15t, C18:3-9t,12c,15c, and C18:3-9t,12t,15c/C18:3-9t,12c,15t) in soybean oil heated to temperatures exceeding 200 °C were compared with those of the control sample. The heating temperature and duration should be considered to reduce the formation of trans-fatty acids during thermal treatment.

Structure elucidation and toxicity analyses of the radiolytic products of aflatoxin B1 in methanol-water solution.

The identification of the radiolytic products of mycotoxins is a key issue in the feasibility study of gamma ray radiation detoxification. Methanol-water solution (60:40, v/v) spiked with aflatoxin B(1) (AFB(1); 20 mg L(-1)) was irradiated with Co(60) gamma ray to generate radiolytic products. Liquid chromatography-quadruple time-of-flight mass spectrometry was applied to identify the radiolytic products of AFB(1). Accurate mass and proposed molecular formulas with a high-matching property of more than 20 radiolytic products were obtained. Seven key radiolytic products were proposed based on the molecular formulas and tandem mass spectrometry spectra. The analyses of toxicity and formation pathways were proposed based on the structure of the radiolytic products. The addition reaction caused by the free-radical species in the methanol-water solution resulted in the formation of most radiolytic products. Based on the structure-activity relationship analysis, the toxicity of radiolytic products was significantly reduced compared with that of AFB(1) because of the addition reaction that occurred on the double bond in the terminal furan ring. For this reason, gamma irradiation is deemed an effective tool for the detoxification of AFB(1).