Article pubs.acs.org/JAFC
Antioxidants Inhibit Formation of 3‑Monochloropropane-1,2-diol Esters in Model Reactions Chang Li, Hanbing Jia, Mingyue Shen, Yuting Wang, Shaoping Nie, Yi Chen, Yongqiang Zhou, Yuanxing Wang, and Mingyong Xie* State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, Jiangxi, China ABSTRACT: The capacities of six antioxidants to inhibit the formation of 3-monochloropropane-1,2 diol (3-MCPD) esters were examined in this study. Inhibitory capacities of the antioxidants were investigated both in chemical models containing the precursors (tripalmitoyl glycerol, 1,2-dipalmitoyl-sn-glycerol, monopalmitoyl glycerol, and sodium chloride) of 3-MCPD esters and in oil models (rapeseed oil and sodium chloride). Six antioxidants, butylated hydroxytoluene (BHT), butylated hydroxy anisole (BHA), tert-butyl hydroquinone (TBHQ), propyl gallate (PG), L-ascorbyl palmitate (AP), and α-tocopherol (VE), were found to exhibit inhibiting capacities on 3-MCPD ester formation both in chemical models and in oil models. TBHQ provided the highest inhibitory capacity both in chemical models and in oil models; 44% of 3-MCPD ester formation was inhibited in the presence of TBHQ (66 mg/kg of oil) after heating of rapeseed oil at 230 °C for 30 min, followed by PG and AP. BHT, BHA, and VE appeared to have weaker inhibitory abilities in both models. VE exhibited the lowest inhibition rate; 22% of 3-MCPD esters were inhibited in the presence of VE (172 mg/kg of oil) after heating of rapeseed oil at 230 °C for 30 min. In addition, the inhibition rates of PG and VE decreased dramatically with an increase in temperature or heating time. The results suggested that some antioxidants, such as TBHQ, PG, and AP, could be the potential inhibitors of 3-MCPD esters in practice. KEYWORDS: 3-MCPD esters, antioxidants, inhibition, chemical model, oil model
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INTRODUCTION Recently, 3-monochloropropane-1,2-diol (3-MCPD) esters have drawn the attention of food scientists and consumers worldwide. 3-MCPD esters were found in a wide range of foodstuffs, such as bread,1 potato products,2,3 edible fats and oils,4−6 cereal,7 coffee,8 malts,9 infant and baby foods,10 goat’s milk,11 and even human breast milk.12 The formation of 3MCPD esters was attributed to deodorization during the edible oil refining process.13 3-MCPD esters were also formed in chemical models at high temperatures. 14−16 Rahn and Yaylayan 17 proposed four pathways of 3-MCPD ester formation, including (a) direct nucleophilic attack at the glycerol carbon carrying an ester group, (b) direct nucleophilic attack at the glycerol carbon carrying a hydroxyl group, (c) formation of acyloxonium ion, and (d) formation of glycidol ester with an epoxide ring. Although these potential mechanisms were proposed, there are still few published data supporting them. A free radical mechanism of 3-MCPD diester formation using a diacylglycerol (DAG) as a precursor was reported.18 According to this mechanism, formation of a cyclic acyloxonium free radical intermediate and its reaction with a chlorine radical or a chlorine compound are included. More recently, the mechanisms for formation of 3-MCPD di- and monoesters from triacylglycerol (TAG), involving the formation of either a cyclic acyloxonium or a glycidol ester radical intermediate, were proven in model reactions.19 It appears that the formation of radical intermediate is one of the critical steps in generating 3-MCPD esters during heat treatment. Butylated hydroxytoluene (BHT), butylated hydroxy anisole (BHA), tert-butyl hydroquinone (TBHQ), propyl gallate (PG), ascorbyl palmitate (AP), and α-tocopherol (vitamin E, VE) are commonly used as antioxidants in a large number of edible oils © XXXX American Chemical Society
and fat-containing foods. Antioxidants were proven to protect lipids against oxidation by scavenging or quenching free radicals.20,21 In addition, antioxidants can serve not only as free radical scavengers, inactivators of peroxides and reactive oxygen species (ROS), and quenchers of secondary lipid oxidation products22,23 but also as quenchers of reactive nitrogen species (RNS) and reactive chlorine species (RCS)24 generated in edible oil during heat treatment. However, to the best of our knowledge, there are no any reports about their effects on the formation of 3-MCPD esters. On the basis of our findings and the findings mentioned above, this study was proposed. The study was conducted by adding six antioxidants to model reaction mixtures to determine their effects on the formation of 3-MCPD esters during heating. The results may provide new insights into the mechanism of formation of 3-MCPD esters and provide novel approaches for mitigation of 3-MCPD esters.
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MATERIALS AND METHODS
Reagents and Chemicals. Tripalmitoyl glycerol (glyceryl tripalmitate, TPG, ≥99%), 1,2-dipalmitoyl-sn-glycerol (DPG, ≥99%), monopalmitoyl glycerol (MPG, ≥99%), and α-tocopherol (VE, synthetic, ≥96%) were purchased from Sigma-Aldrich (St. Louis, MO). d5-3-MCPD-1,2-bis-palmitoyl ester and 3-MCPD-1,2-bispalmitoyl ester were from Toronto Research Chemicals (Toronto, ON). Butylated hydroxytoluene (BHT, >99.7%), butylated hydroxy anisole (BHA, >99%), tert-butyl hydroquinone (TBHQ, >99%), propyl gallate (PG, >99%), L-ascorbyl palmitate (Asc-6P, AP, Received: July 18, 2015 Revised: October 11, 2015 Accepted: October 18, 2015
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DOI: 10.1021/acs.jafc.5b03503 J. Agric. Food Chem. XXXX, XXX, XXX−XXX
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and the correlation coefficient was 0.9994 (R2). The limit of detection (LOD) and the limit of quantitation (LOQ) were determined by standard solutions based on signal-to-noise ratios (S/N) of 3:1 for LOD and 10:1 for LOQ. The LOQ was verified by analyzing spiked samples at the respective level. The LOD of the method was 25 μg/kg, and the LOQ was 50 μg/kg. Statistical Analysis. The results were analyzed by one-way analysis of variance and Duncan’s multiple tests to identify significant differences in comparison of means. P values of ≤0.05 were considered significant. All analyses were performed using SPSS19.0 for Windows (SPSS Inc., Chicago, IL).
>99%), sodium methoxide, sodium sulfate anhydrous, sodium bromide, phenylboronic acid, and hexadecane (≥99%) were obtained from Aladdin Industrial Inc. (Shanghai, China). Toluene, tert-butyl methyl ether, methanol, isohexane, ethyl acetate, diethyl ether isooctane, sulfuric acid, and sodium chloride were purchased from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China). Methods. Effects of Antioxidants on the Formation of 3-MCPD Esters in Chemical Models. MPG, DPG, and TPG were dissolved in hexadecane and prepared at a final concentration of 0.01 mol/L. BHT, BHA, TBHQ, PG, AP, and VE were dissolved in ethanol at a concentration of 0.001 mol/L; 5.9 mg of sodium chloride and 1 mL of an antioxidant solution were added to 10 mL of a glyceride (MPG, DPG, and TPG) solution in a glass tube. After the solutions had been mixed thoroughly, the model reactions were performed at 230 °C for 30 min in a silicon oil bath. After reaction, the mixtures were cooled to ambient temperature and then stored at 4 °C before further analysis. All experiments were repeated three times. Effects of Antioxidants on the Formation of 3-MCPD Esters in the Oil Model System. Crude rapeseed oil was produced by cold squeezing. Crude oil was filtered and homogenized before being introduced into model reaction mixtures. BHT, BHA, TBHQ, PG, AP, and VE were prepared in ethanol at a concentration of 0.002 mol/L. The crude oil (5 g), sodium chloride (25 mg), and antioxidant (1.0 mL) were placed in a glass tube together and mixed completely. The mixtures were heated at 230 °C for 30 min in a silicon oil bath. After reaction, the glass tubes were cooled to ambient temperature and stored at 4 °C before further analysis. All experiments were repeated three times. For more insights into the effects of antioxidants on the formation of 3-MCPD esters in oil models, different heating time courses and different heating temperatures were also investigated. Analysis of 3-MPCD Esters. The content of 3-MCPD esters was determined according to DGF method C-VI 18 (10) part B. The sample was dissolved in tert-butyl methyl ether (t-BME) and spiked with d5-3-MCPD-1,2-bis-palmitoyl ester. A transesterification was performed by addition of sodium methoxide. The reaction was stopped by addition of an excess of an acidic NaBr solution. After multiple extractions with the mixture of diethyl ether and ethyl acetate, free 3-MCPD was derivatizated with phenyboronic acid (PBA) in the organic phase. The derivative was dried with a nitrogen flow and then resolved in isooctane. After being filtered, the solution was analyzed by gas chromatography−mass spectrometry (GC−MS). Samples were analyzed by GC−MS using an Agilent model 7890 A gas chromatograph equipped with a model 5975C selective mass selective detector and a split/splitless injector including an autosampler. Splitless was set as the injection mode, and detection was performed in selected ion monitoring mode. A HP 5 MS capillary column (Agilent, Waldbronn, Germany; 5% phenyl, 95% dimethylpolysiloxane; 30 m × 0.25 mm, 0.25 μm film thickness) was used for separation. The injection volume was set at 1 μL. The injector temperature was kept at 280 °C, and ultrapure grade helium was used as the carrier gas with a flow rate of 1.0 mL/min. The GC oven temperature was programmed from an initial temperature of 85 °C (isothermal for 0.5 min) and then increased at a rate of 6 °C/min to 150 °C, a rate of 12 °C/min to 180 °C, and a rate of 25 °C/min to 280 °C (isothermal for 7.16 min). Quantitative analysis was conducted by monitoring characteristic ions (quantifier) at m/z 147 (3-MCPD) and m/z 150 (d5-3-MCPD). Ions at m/z 196 (3-MCPD) and m/z 201 (d53-MCPD) were used as qualifiers. The dwell time for each m/z was set at 50 ms. Quantitation of the 3-MCPD esters was conducted by multiplying the ratio of signal areas of the analyte and the isotopically labeled surrogate standard based on corresponding ion traces with the spiking level of the isotopically labeled surrogate standard in each assay. Tests were performed in triplicate. The means ± the standard deviation (SD) of levels were expressed as micrograms of 3-MCPD per kilogram of oil or fat. In this work, five calibration standards were analyzed in triplicate for the determination of 3-MCPD esters. Linearity relationships were checked, plotting concentration against the peak area ratio of the standard and the internal standard. The linearity for the GC−MS method was in the range of 0.05−5.0 mg/kg,
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RESULTS AND DISCUSSION Effects of Antioxidants on the Formation of 3-MCPD Esters in Chemical Models. Monoglyceride, diglyceride, and triglyceride were reported to be the precursors of 3-MCPD esters in previous studies.14−16,18,19,25 Moreover, a radical intermediate mechanism was proposed for generation of 3MCPD esters from diglyceride and triglyceride under a hightemperature and low-moisture condition.18,19 In the study presented here, MPG, DPG, and TPG were used as the precursors in the chemical model reactions with sodium chloride to generate 3-MCPD esters. BHT, BHA, TBHQ, PG, AP, and VE were added to each glyceride model. Their effects on the formation of 3-MCPD esters in chemical models were evaluated. As shown in Figure 1, all six selected antioxidants
Figure 1. Inhibition rates of antioxidants to 3-MCPD ester formation in chemical models (at 230 °C for 30 min). Data are means ± SD (n = 3). The concentrations of 3-MCPD esters in MPG, DPG, and TPG models without an antioxidant were 8921 ± 106, 7678 ± 113, and 1098 ± 68 μg/kg, respectively (n = 3). In MPG models, the levels of addition of antioxidants were as follows: BHT, 0.67% (calculated with mass fraction of antioxidant in glyceride); BHA, 0.55%; TBHQ, 0.50%; PG, 0.64%; AP, 1.25%; VE, 1.30%. In DPG models, the levels of addition of antioxidants were as follows: BHT, 0.39%; BHA, 0.32%; TBHQ, 0.29%; PG, 0.37%; AP, 0.73%; VE, 0.76%. In TPG models, the levels of addition of antioxidants were as follows: BHT, 0.27%; BHA, 0.22%; TBHQ, 0.21%; PG, 0.26%; AP, 0.51%; VE, 0.53%.
appeared to inhibit 3-MCPD ester formation in chemical models. TBHQ provided the highest inhibition rate (mean value), in both the MPG model and the DPG model. In the TPG model, AP was the strongest inhibitor among the selected antioxidants. AP showed no significant differences (P > 0.05) in inhibition rate in three chemical models (MPG, DPG, and TPG), which was different from the case for other antioxidants. B
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radicals formed during lipid peroxidation might initiate primary reactions in the procedure of 3-MCPD ester formation. TBHQ is regarded as the best antioxidant for protecting edible oils against oxidation. In edible oil, TBHQ as a diphenolic antioxidant can react with peroxy radicals to form a semiquinone and the semiquinone can consequently react with another peroxy radical to inhibit peroxy radicals.23 That might be the mechanism of inhibiting 3-MCPD esters for TBHQ. To the best of our knowledge, the antiradical efficiency of antioxidants tends to be related to their chemical structures, for instance, the position and number of phenolic groups. PG has a degree of hydroxylation (with three phenolic hydroxyl groups) higher than those of the other antioxidants; namely, it is a stronger electron donator and can inactivate free radicals generated in reaction models. AP is an antioxidant with multiple functions, including scavenging oxygen in the presence of metal ions, shifting the redox potential of food systems to the reducing range, acting synergistically with chelators, and regenerating primary antioxidants.28 AP had a strong singlet oxygen quenching ability and antioxidative activity in oil oxidation.29 In addition, AP can be hydrolyzed by the digestive system to provide nutritionally available ascorbic acid and palmitic acid, so it has been generally regarded as safe (GRAS); no restriction on usage levels has been imposed in the United States and the European Union. To examine the effects of heating time on the inhibition rates in oil models, the reaction mixtures with or without an antioxidant were heated for different periods of time. As shown in Table 1, the contents of 3-MCPD esters increased with an increase in heating time, both in control and antioxidant groups. The inhibition rates decreased as the heating time was prolonged to 30 min, and the inhibition rates decreased, except for those in the TBHQ model from 30 to 60 min (Figure 3). TBHQ, PG, and AP exhibited no significant differences (P ≤ 0.05) in inhibition rates when the models were heated for 15 min, as did BHT, BHA, and VE. By contrast, TBHQ seemed to be more robust in inhibiting the formation of 3-MCPD esters in the oil models during the setting time periods. While the inhibition rate of PG dropped from 48.5% (15 min) to 16.6% (60 min), the descending range was the greatest among those of six antioxidants. It is well-known that PG is susceptible to heat and TBHQ has good heat endurance. Therefore, with the increase in heating time, they exhibited evidently different stabilities. The capability of antioxidants decreased to different degrees with an increase in heating time, and the contents of 3MCPD esters increased with an increase in heating time (Table 1). The increase of the 3-MCPD esters and the decline in the activity of the antioxidants, which were attributed to the
In the DPG model, the inhibition abilities of BHT and BHA were stronger than those in MPG and TPG models (P ≤ 0.05). As for VE, the inhibition rates in three chemical models decreased in the order MPG > DPG > TPG and were significantly different (P ≤ 0.05) from each other. Effects of Antioxidants on the Formation of 3-MCPD Esters in Oil Model Systems. Studies5,13,14,26,27 showed that 3-MCPD esters were formed during edible oil refining. Furthermore, 3-MCPD esters were also generated in an oil/ chloride mixture during heat treatment.16,25 In the study presented here, oil models were set up by mixing oil with sodium chloride for generating 3-MCPD esters. Crude (cold pressed) rapeseed oil was selected as a substrate in the oil model reactions. Figure 2 presents the inhibition rates of six
Figure 2. Inhibition rates of the antioxidants to 3-MCPD ester formation in rapeseed oil model systems (at 230 °C for 30 min). Data are means ± SD (n = 3). The values not sharing a common letter (a, b, c, and d) are significantly different (P ≤ 0.05). The concentration of 3MCPD esters formed in the oil model without an antioxidant was 2238 ± 89 μg/kg (n = 3). The levels of addition of antioxidants in models were 88 mg/kg (BHT), 72 mg/kg (BHA), 66 mg/kg (TBHQ), 84 mg/kg (PG), 166 mg/kg (AP), and 172 mg/kg (VE).
selected antioxidants with respect to the formation of 3-MCPD esters in rapeseed oil models. Like the cases in chemical models, TBHQ, PG, and AP exhibited capacities to inhibit the formation of 3-MCPD esters greater than those of three other antioxidants in the oil models, which agreed with their capacities to prevent oil oxidation in edible oil.22 According to the proposed free radical-mediated mechanism,18 the peroxy
Table 1. Effects of the Antioxidants on the Contents of 3-MCPD Esters in the Rapeseed Oil Model System at 230 °C for Different Periods of Time (15, 30, 45, and 60 min)a 3-MCPD esters (μg/kg) (mean ± SD) (n = 3) time (min) 0 15 30 45 60
control 0 968 2238 2721 3018
± ± ± ±
26 89 99 73
BHT a a a a
N/A 621 1583 2098 2399
± ± ± ±
21 62 87 66
BHA b b b b
N/A 605 1540 1978 2361
± ± ± ±
30 49 81 81
TBHQ N/A 489 1256 1519 1728
b b b b
± ± ± ±
19 51 66 71
PG c c c d
N/A 499 1406 2099 2516
± ± ± ±
20 46 79 69
AP c bc b c
N/A 502 1346 1848 2299
± ± ± ±
22 39 88 58
VE c bc bc b
N/A 633 1746 2169 2677
± ± ± ±
23 44 80 62
b d b c
3-MCPD ester contents labeled with different lowercase letters at the same heating time were significantly different (P ≤ 0.05). N/A, not applicable. The levels of addition of antioxidants in models were 88 mg/kg (BHT), 72 mg/kg (BHA), 66 mg/kg (TBHQ), 84 mg/kg (PG), 166 mg/kg (AP), and 172 mg/kg (VE). a
C
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different degrees as the temperatures were higher than 210 °C; in particular, the inhibition abilities of PG and VE decreased sharply. BHT had the lowest inhibition rates at 180 and 210 °C; however, it had relatively higher inhibition rates at 240 and 270 °C. TBHQ possessed the highest inhibition rate at all setting temperatures. The observations suggested that at lower temperatures (180−210 °C, for example), the antioxidants except PG were more robust in inhibiting 3-MCPD esters in oil models. The instability of PG in inhibiting 3-MCPD esters was evident, when the temperature increased. The activities of antioxidants were stronger at lower temperatures, and the relative rate of antioxidant activity decreased with an increase in temperature.30 Furthermore, the level of 3-MCPD esters increased with an increase in in temperature in the study presented here (data not shown). In general, among six antioxidants, TBHQ, PG, and AP were the most effective inhibitors. TBHQ was robust in terms of its ability to inhibit 3-MCPD esters, while PG and VE were vulnerable to high temperatures. In general, TBHQ, PG, and AP were potential inhibitors of 3-MCPD esters in food heat processing, especially at a lower temperature. The antioxidants used in this research were all approved as food additives by organizations such as FAO/WHO, EU, FDA, etc. The amounts of antioxidants used in the oil model systems can also be used in the oil industry, because they are not higher than the maximal limits. However, the mechanism of inhibition of 3-MCPD esters by antioxidants, the correlation between the inhibition ability and antioxidative property, and their kinetics need to be srudied further.
Figure 3. Inhibition rates of the antioxidants to the formation of 3MCPD esters in rapeseed oil models upon being heated at 230 °C for 15, 30, 45, and 60 min. Data are expressed as means. The concentrations of 3-MCPD esters formed in the oil model without an antioxidant were 968 ± 26 μg/kg for 15 min, 2238 ± 89 μg/kg for 30 min, 2721 ± 99 μg/kg for 45 min, and 3018 ± 73 μg/kg for 60 min (n = 3). The levels of addition of antioxidants in models were 88 mg/ kg (BHT), 72 mg/kg (BHA), 66 mg/kg (TBHQ), 84 mg/kg (PG), 166 mg/kg (AP), and 172 mg/kg (VE).
increase in duration, might lead to the dramatic decrease in inhibition rates with the increase in time. In addition, different heating temperatures were investigated for their effects on the inhibition rates in oil models with and without addition of an antioxidant. As shown in Figure 4, when the temperature increased from 180 to 210 °C, the inhibition rate of each antioxidant almost had no change except that of PG. The inhibition rates of different antioxidants declined to
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AUTHOR INFORMATION
Corresponding Author
*State Key Laboratory of Food Science and Technology, Nanchang University, 235 Nanjing East Rd., Nanchang 330047, China. Telephone: 0086-791-83969009. E-mail: myxie@ncu. edu.cn. Funding
This research was supported by the National Key Technology R&D Program of China (Grant 2014BAD04B03), the National Basic Research Program of China (“973” Program) (Grant 2012CB720805), and the Natural Science Foundation of Jiangxi Province, China (Grant 20142BAB204002). Notes
The authors declare no competing financial interest.
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REFERENCES
(1) Doležal, M.; Kertisová, J.; Zelinková, Z.; Velíšek, J. Analysis of bread lipids for 3-MCPD esters. Czech J. Food Sci. 2009, 27, S417− S420. (2) Ilko, V.; Zelinková, Z.; Doležal, M.; Velíšek, J. 3-Chloropropane1, 2-Diol fatty acid esters in potato products. Czech J. Food Sci. 2011, 29, 411−419. (3) Zelinková, Z.; Doležal, M.; Velíšek, J. 3-Chloropropane-1, 2-diol fatty acid esters in potato products. Czech J. Food Sci. 2009, 27, S421− S424. (4) Zelinková, Z.; Svejkovská, B.; Velíšek, J.; Doležal, M. Fatty acid esters of 3-chloropropane-1, 2-diol in edible oils. Food Addit. Contam. 2006, 23, 1290−1298. (5) Craft, B. D.; Chiodini, A.; Garst, J.; Granvogl, M. Fatty acid esters of monochloropropanediol (MCPD) and glycidol in refined edible oils. Food Addit. Contam., Part A 2013, 30, 46−51.
Figure 4. Inhibition rates of the antioxidants to the formation of 3MCPD esters in rapeseed oil models upon being heated for 30 min at 180, 210, 240, and 270 °C. The inhibition rates are expressed as mean values (n = 3). The concentrations of 3-MCPD esters formed in oil model without an antioxidant were 1399 ± 66 μg/kg for 180 °C, 1616 ± 71 μg/kg for 210 °C, 2268 ± 78 μg/kg for 240 °C, and 2568 ± 87 μg/kg for 270 °C (n = 3). The levels of addition of antioxidants in models were 88 mg/kg (BHT), 72 mg/kg (BHA), 66 mg/kg (TBHQ), 84 mg/kg (PG), 166 mg/kg (AP), and 172 mg/kg (VE). D
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refined palm (Elaeis guineensis) oil and related fractions. Food Addit. Contam., Part A 2012, 29, 29−37. (27) Ramli, M. R.; Siew, W. L.; Ibrahim, N. A.; Hussein, R.; Kuntom, A.; Abd. Razak, R. A.; Nesaretnam, K. Effects of Degumming and Bleaching on 3-MCPD Esters Formation During Physical Refining. J. Am. Oil Chem. Soc. 2011, 88, 1839−1844. (28) Madhavi, D.; Deshpande, S.; Salunkhe, D. K. Technological Aspects of Food Antioxidants. In Food antioxidants: Technological, toxicological and health perspectives; Madhavi, D. L., Singhal, R. S., Kulkarni, P. R., Eds.; CRC Press: New York, 1995; pp 159−220. (29) Lee, K.; Jung, M.; Kim, S. Quenching mechanism and kinetics of ascorbyl palmitate for the reduction of the photosensitized oxidation of oils. J. Am. Oil Chem. Soc. 1997, 74, 1053−1057. (30) Reblová, Z. Effect of temperature on the antioxidant activity of phenolic acids. Czech J. Food Sci. 2012, 30, 171−177.
(6) Li, C.; Nie, S. P.; Zhou, Y. Q.; Xie, M. Y. Exposure assessment of 3-monochloropropane-1, 2-diol esters from edible oils and fats in China. Food Chem. Toxicol. 2015, 75, 8−13. (7) Hamlet, C.; Sadd, P. Chloropropanols and their esters in cereal products. Czech J. Food Sci. 2004, 22, 259−262. (8) Doležal, M.; Chaloupská, M.; Divinová, V.; Svejkovská, B.; Velišek, J. Occurrence of 3-chloropropane-1,2-diol and its esters in coffee. Eur. Food Res. Technol. 2005, 221, 221−225. (9) Divinová, V.; Doležal, M.; Velišek, J. Free and bound 3chloropropane-1, 2-diol in coffee surrogates and malts. Czech J. Food Sci. 2007, 25, 39−47. (10) Zelinková, Z.; Doležal, M.; Velíšek, J. Occurrence of 3chloropropane-1,2-diol fatty acid esters in infant and baby foods. Eur. Food Res. Technol. 2009, 228, 571−578. (11) Cerbulis, J.; Parks, O. W.; Liu, R. H.; Piotrowski, E. G.; Farrell, H. M., Jr Occurrence of diesters of 3-chloro-1, 2-propanediol in the neutral lipid fraction of goats’ milk. J. Agric. Food Chem. 1984, 32, 474−476. (12) Zelinková, Z.; Novotny, O.; Schurek, J.; Velišek, J.; Hajslová, J.; Doležal, M. Occurrence of 3-MCPD fatty acid esters in human breast milk. Food Addit. Contam., Part A 2008, 25, 669−76. (13) Hrncirik, K.; van Duijn, G. An initial study on the formation of 3-MCPD esters during oil refining. Eur. J. Lipid Sci. Technol. 2011, 113, 374−379. (14) Freudenstein, A.; Weking, J.; Matthäus, B. Influence of precursors on the formation of 3-MCPD and glycidyl esters in a model oil under simulated deodorization conditions. Eur. J. Lipid Sci. Technol. 2013, 115, 286−294. (15) Shimizu, M.; Vosmann, K.; Matthäus, B. Generation of 3monochloro-1,2-propanediol and related materials from tri-, di-, and monoolein at deodorization temperature. Eur. J. Lipid Sci. Technol. 2012, 114, 1268−1273. (16) Ermacora, A.; Hrncirik, K. Influence of oil composition on the formation of fatty acid esters of 2-chloropropane-1,3-diol (2-MCPD) and 3-chloropropane-1,2-diol (3-MCPD) under conditions simulating oil refining. Food Chem. 2014, 161, 383−9. (17) Rahn, A. K. K.; Yaylayan, V. A. What do we know about the molecular mechanism of 3-MCPD ester formation? Eur. J. Lipid Sci. Technol. 2011, 113, 323−329. (18) Zhang, X.; Gao, B.; Qin, F.; Shi, H.; Jiang, Y.; Xu, X.; Yu, L. L. Free radical mediated formation of 3-monochloropropanediol (3MCPD) fatty acid diesters. J. Agric. Food Chem. 2013, 61, 2548−55. (19) Zhang, Z.; Gao, B.; Zhang, X.; Jiang, Y.; Xu, X.; Yu, L. L. Formation of 3-Monochloro-1,2-propanediol (3-MCPD) Di- and Monoesters from Tristearoylglycerol (TSG) and the Potential Catalytic Effect of Fe2+ and Fe3+. J. Agric. Food Chem. 2015, 63, 1839−1848. (20) Van Aardt, M.; Duncan, S. E.; Long, T. E.; O’Keefe, S. F.; Marcy, J. E.; Sims, S. R. Effect of antioxidants on oxidative stability of edible fats and oils: thermogravimetric analysis. J. Agric. Food Chem. 2004, 52, 587−591. (21) Cort, W. M. Antioxidant activity of tocopherols, ascorbyl palmitate, and ascorbic acid and their mode of action. J. Am. Oil Chem. Soc. 1974, 51, 321−325. (22) Akoh, C. C.; Min, D. B. Antioxidants. In Food lipids: Chemistry, nutrition, and biotechnology, 3rd ed.; Reische, D. W., Lillard, D. A., Eitenmiller, R. R., Eds.; CRC Press: Boca Raton, FL, 2008; pp 409− 434. (23) Shahidi, F.; Janitha, P.; Wanasundara, P. Phenolic antioxidants. Crit. Rev. Food Sci. Nutr. 1992, 32, 67−103. (24) Shahidi, F. Antioxidants in Grapes and Wine: Chemistry and Health Effects. In Natural antioxidants: Chemistry, health effects, and applications; Williams, R. L., Elliot, M. S., Eds.; The American Oil Chemists Society: Champaign, IL, 1997; pp 150−173. (25) Svejkovská, B.; Doležal, M.; Velišek, J. Formation and decomposition of 3-chloropropane-1,2-diol esters in models simulating processed foods. Czech J. Food Sci. 2006, 24, 172−179. (26) Destaillats, F.; Craft, B. D.; Sandoz, L.; Nagy, K. Formation mechanisms of monochloropropanediol (MCPD) fatty acid diesters in E
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