Influences of Light Intensity and Î²-Carotene on Polycyclic Aromatic

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Influences of light intensity and #-carotene on polycyclic aromatic hydrocarbons and aldehydes in vegetable oil: a case study using palm oil Guangyi Gong, Shimin Wu, and Xiaojing Wu J. Agric. Food Chem., Just Accepted Manuscript • DOI: 10.1021/acs.jafc.8b04096 • Publication Date (Web): 03 Oct 2018 Downloaded from http://pubs.acs.org on October 4, 2018

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Journal of Agricultural and Food Chemistry

75x42mm (300 x 300 DPI)

ACS Paragon Plus Environment


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Influences of light intensity and β-carotene on polycyclic aromatic

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hydrocarbons and aldehydes in vegetable oil: a case study using palm oil

3 4

Guangyi Gong a, b, Shimin Wu a, b, *, Xiaojing Wua, b

5 6

a

7

Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China

8

b

9

Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China

Department of Food Science and Technology, School of Agriculture and Biology,

Key Laboratory of Urban Agriculture (South), Ministry of Agriculture, Shanghai

10 11

Running title: Effects of light intensity on PAHs and HAEs

12

*

Corresponding author: E-mail: [email protected]; Tel./Fax: +86 21 34205717

13

1


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Abstract

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This study investigated the effects of three light intensities on four types of palm oils

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during consecutive storage for 12 months at 4 °C. The concentrations of

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4-hydroxy-2-trans-hexenal (4-HHE), 4-hydroxy-2-trans-nonenal (4-HNE), PAH4 and

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PAH8 in the oils significantly increased with the increasing light intensity after

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storage. The red palm oil had the lowest rate of increase of 4-HNE, while 5° palm oil

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had the highest rate of increase of the PAH, OPAH, 4-HNE and peroxide values

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during storage. For the same type of oil, OPAHs increased significantly under a light

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intensity of 6000 lux (lx) after storage. The increasing concentrations of 9FO, ATQ

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and BaPO in the oils stored at 6000 lx showed a positive relation to their

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corresponding parent PAHs, indicating that PAH oxidation occurred at 6000 lx. The

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results suggest that light intensity and β-carotene may control PAHs, OPAHs and

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4-HAEs for vegetable oil storage, transportation and retail.

27 28

Keywords: unsaturated fatty acid, decolourization, oxidation, formation mechanism,

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toxicity, antioxidants, benzo[a]pyrene, inhibition

30

2



31

Introduction

32 33

The existence of harmful organic compounds in edible oils, such as

34

4-hydroxy-trans-alkenals (4-HAEs) and polycyclic aromatic hydrocarbons (PAHs),

35

has aroused great attention. The 4-HAEs are a type of lipid-oxidation pollutant.

36

Among them, most studies focus on 4-hydroxy-2-trans-hexenal (4-HHE) and

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4-hydroxy-2-trans-nonenal (4-HNE).1 They are reported to be mutagenic and

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tumorigenic.2-4 Similarly, PAHs are also reported to be highly toxic and biotoxic.

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Many previous studies have indicated the high concentration of PAHs and 4-HAEs

40

in edible oils. Zheng et al. detected concentrations of PAHs in 150 vegetable oil

41

samples, which included rapeseed oil, peanut oil, sesame oil and tea seed oil. The

42

results showed that the concentration of benzo[a]pyrene was as great as 10.88 µg/kg,

43

while the concentration of total PAHs was as great as 91.30 µg/kg.5 Torres et al. used

44

UHPLC-fluorescence to analyse PAHs in vegetable oils, including coconut oil,

45

safflower oil, evening primrose oil and linseed oil. The total concentration of

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benzo[a]anthracene, chrysene, benzo[k]fluoranthene and benzo[a]pyrene reached as

47

high as 4.95 µg/kg.6 The concentration of HAEs ranged from 0.2 to 60 mg/kg in

48

frying vegetable oils.7 All these studies showed the necessity to monitor the levels of

49

4-HAEs and PAHs in vegetable oils. However, though widely used in the food

50

industry, PAH concentrations in palm oils were sparsely studied. As far as we know,

51

there has been no research focus on the comparison between different types of palm

52

oils. 3


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The concentrations of PAHs and 4-HAEs in edible oils are influenced by storage

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conditions. Our previous study indicated that PAHs may form and change during

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vegetable oil storage. Under the storage conditions of 25 °C and 4 °C, the

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concentrations of PAHs also increased during the storage, and increased with the

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storage temperature.8 These studies indicated that storage at a lower temperature

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could defer the formation of PAHs. Changes of 4-HAEs in edible oils also demand

59

investigation.

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In addition to storage temperature and time, light exposure is a main factor in the

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deterioration of lipids and edible oils. Light can also cause changes in the PAH and

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4-HAE level during storage. A previous study indicated that photo-oxidation and

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photolysis during storage may be an important process in determining the fate of

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PAHs.9 Wu et al. studied photodegradation of three PAHs (fluorene, phenanthrene and

65

pyrene) in solution, with the results showing that the degradation of PAHs exhibited

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first-order kinetics in solution.10 Nadal et al. studied the effect of UV radiation on the

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photodegradation of PAHs, finding that the concentration of acenaphthene,

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fluoranthene and pyrene decreased in the UV treated groups.11 However, little has

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been known about the effect of light on PAHs in edible oil. As for 4-HAEs, many

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discussions on the effects of light on 4-HNE and 4-HHE were presented, while no

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data were available.

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Moreover, with high contents of saturated fatty acids and natural antioxidant, palm

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oil has excellent high heat stability during frying. China witnessed the sustainable

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growth in palm oil consumption during the past five years. Conversely, few researches 4



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have focused on the PAHs and HAEs contamination in palm oils, especially during

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the storage process. In this study, we chose 5° palm oil, 8° palm oil for their potential

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uses in family, while 24° palm oil for its wide application in food industry. Besides

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the above three types of palm oils, red palm oil gets great attention for its very

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abundant β-carotene. According to our previous investigation, few differences were

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observed among concentrations of vitamin E in the four selected palm oils.12 To

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further investigate the effects of endogenous β-carotene on PAHs and HAEs contents,

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we chose red palm oil for comparison. This work aims to investigate the effects of

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three different light intensities (0 lx, 600 lx, and 6000 lx) on PAHs, OPAHs and

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4-HAEs in these four types of palm oils with different melting points during storage at

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4 °C for 12 consecutive months.

86 87

2. Materials and methods

88 89

2.1. Materials and reagents

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All solvents used during extraction and chromatographic analysis in this study were

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of high-performance liquid chromatography (HPLC) grade. Methanol, n-pentane,

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n-hexane, dichloromethane, acetone and acetonitrile were purchased from CNW

93

Technologies GmbH (Darmstadt, Germany). Water was purified with a Milli-Q water

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purification system (Millipore, Milford, USA). Standards of 4-HHE and 4-HNE were

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purchased from Cayman Chemical Co. (Ann Arbor, MI, USA). The purity of both

96

standards was 98 % and certificated by the supplier. Standards and their stock 5


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solutions, with the concentration of 100 µg/mL, were stored at -80 °C. The standard

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PAH mixture consisted of 16 PAHs including naphthalene (NA), acenaphthylene (Ap),

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acenaphthene (Ac), fluorene (F), phenanthrene (Phe), anthracene (Ant), fluoranthene

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(Fl), pyrene (Pyr), benzo[a]anthracene (BaA), chrysene (Chr), benzo[b]fluoranthene

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(BbF), benzo[k]fluoranthene (BkF), benzo[a]pyrene (BaP), indeno[1,2,3-c,d]pyrene

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(Ip), dibenzo[a,h] anthracene (DBahA) and benzo[ghi]perylene (BghiP). These 16

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PAHs were dissolved in 1 mL dichloromethane (AccuStandard, New Haven, CT, USA)

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at concentrations of 0.2 mg/L each. The compound 9-fluorenone (9FO) and

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anthracene-9,10-dione (ATQ) were bought from Dr Ehrenstorfer Gmbh (Augsburg,

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Germany). Benzo[a] anthracene-7,12-dione (BaAQ) was supplied by AccuStandard

107

(New

108

9,10-dihydrobenzo[a]pyren-7(8H)-one

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(Trondheim, Norway). Standard stock solutions were prepared by weighing neat

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OPAH crystals (4.40-14.80 mg) and dissolving them in dichloromethane. The final

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concentration of each OPAH ranged from 0.08 to 0.28 mg/mL. Eight calibration

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solutions were prepared from the stock solutions and the concentration of each PAH

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and OPAH ranged from 5 to 600 ng/mL. The calibration solutions were prepared prior

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to each analysis using the stock solutions kept at -20 °C. The derivatives

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O-(2,3,4,5,6-pentafluorobenzyl)

116

supplied by Sigma Aldrich (Bornem, Belgium), and N,O-bis(trimethylsilyl)

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trifluoroacetamide (BSTFA) and trimethylchlorosilane (TMCS) were obtained from

118

Sigma Aldrich (Bellefonte, USA). C18 solid-phase extraction (SPE) cartridges (2 g,

Haven,

CT,

USA).

Benzanthrone

(BaPO)

hydroxylamine

were

obtained

hydrochloride

6


(BZA)

and

from

Chiron

(PFBHA)

were


119

12 mL) and Florisil SPE cartridges (1 g, 6 mL) were purchased from Supelco Inc.

120

(Bellefonte, PA, USA).

121 122

2.2. Storage condition, light intensity and sampling

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Four types of palm oil, including red palm oil, 5° palm oil, 8° palm oil, 24° palm

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oil, were used in this study. The latter three were obtained from Tianjin Longwei Co.

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Ltd (Tianjin, China), with detailed melting points of 4.5 °C, 9.0 °C and 22.5 °C,

126

respectively. The red palm oil was supplied by Malaysian Palm Oil Co. Ltd (Shanghai,

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China) and fortified with β-carotene in a base of 5 ° palm oil, also with the detailed

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melting point of 4.5 °C. The concentration of β-carotene in red palm oil was 520.00

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mg/kg. In contrast, the concentration of β-carotene was 13.20 mg/kg in 5° palm oil,

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14.70 mg/kg in 8° palm oil and 13.80 mg/kg in 24° palm oil, respectively. Detailed

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description of oil samples was provided in our previous study.13 Briefly, unsaturated

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fatty acids content of red palm oil, 5° palm oil, 8° palm oil, 24° palm oil was 56.52 %,

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53.98 %, 50.72 % and 46.89 %, respectively. The concentration of vitamin E in these

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four palm oils was 364.00, 347.00, 380.00 and 359.00 mg/kg, respectively. Before

135

analysis, fifty millilitres of sample oils were packed in 55 mL sealed transparent PET

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plastic bottles (9.10 % headspace) to prevent the additional entrance of oxygen and

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stored in darkness at 4 °C prior to analysis.

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Each oil sample was divided into three storage groups in three different rooms with

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different light intensity under fluorescent cold white lamp: a low light intensity group

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at 0 lx, a medium light intensity group at 600 lx, and a high light intensity group at 7


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6000 lx. The light intensities were measured by illumination meter (TES-1332A; TES

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Electrical Electronic Corporation, Taiwan, China). According to China National

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Standard GB 50034-2013 and our previous measurement, the condition of 0 lx refers

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to dark conditions, and 600 lx represents the typical light intensity of a supermarket,

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while 6000 lx represents direct exposure to sunlight. To receive the same irradiation,

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all analysed samples were arranged in a line at a platform with lamp above. All the oil

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samples were stored at the temperature of 4 °C. In the pre-experiment, we monitored

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each oil sample every week. However, no significant differences were found during

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the first month. For this reason, we adjusted the sampling intervals to three months.

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The entire storage period lasted consecutively for 12 months. The oil samples were

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analysed at the first, third, sixth, ninth and twelfth months. In total, 63 oil samples in

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63 sealed bottles (three initial samples + four oils × three intensities × five times of

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sampling) were analysed and assessed. Each bottled sample was analysed in duplicate

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and discarded after analysis.

155 156 157

2.3. Determination of acid value (AV), peroxide value (POV) and β-carotene The acid value (AV) and peroxide value (POV) of the oils were determined using

158

titrimetry

159

GB5009.227-2016, respectively. The concentration units of AV and POV were

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expressed in mg/g and g/100 g, respectively. The determination of β-carotene was

161

described by our previous research.12

according

to

China

National

Standards

162 8


GB5009.229-2016

and


163

2.4. Determination of 4-HHE and 4-HNE

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The extraction, derivatization, and GC-MS identification of 4-HHE and 4-HNE in

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the oils can be found in our previous report.13 4-HHE and 4-HNE were quantified

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using an external standard method. The standard curves of 4-HHE and 4-HNE were

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prepared by plotting the peak area against the standard concentration (ng/mL). The

168

regression equations for 4-HHE and 4-HNE were as follows: y = 13.136 x+32.027 and

169

y = 11.138 x-214.280, respectively. The coefficients of determination (R2) were

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0.9944 and 0.9922, respectively. The recovery method was determined by spiking the

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samples with 4-HHE and 4-HNE standards at three levels from 10 to 100 ng/mL and

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50 to 500 ng/mL in triplicate, respectively. Recoveries of 4-HHE and 4-HNE were in

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the range of 80.34–91.58 % and 64.52–77.78 %, respectively. Limit of detection

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(LOD) and limit of quantitation (LOQ) were calculated by the signal-to-noise ratio of

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3:1 and 10:1, respectively. The LOD of 4-HHE and 4-HNE was 0.0486 µg/mL and

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0.0129 µg/mL, respectively, while LOQ was 0.1458 µg/mL and 0.0431 µg/mL,

177

respectively.

178 179

2.5. Analysis of PAHs and OPAHs

180

The analytical method of the 16 PAHs included a liquid-liquid extraction and an

181

SPE clean-up followed by GC-MS analysis. The details are the same as our previous

182

procedures.14 Each compound was identified by matching its mass spectrum with that

183

of the external standard and by referring to the NIST2011 mass spectral reference

184

library. An external standard method was used to quantify the 16 PAHs and five 9


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OPAHs. The concentration of each PAH was calculated on the basis of its respective

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calibration curve, which was prepared by plotting the peak area against the standard

187

solutions (5-200 ng/mL). The calibration curves obtained for each PAH showed a

188

good linear response with coefficients of determination (R2) ranging from 0.9930 to

189

1.0000. Detailed validated method was provided in Table 1.

190 191

2.6. Statistical analysis

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All experiments were carried out in triplicate, with all data expressed as the mean

193

value ± standard deviation (SD). The statistical analysis was performed using SPSS

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19.0 software (Chicago, IL, USA). The statistical analysis of variance was conducted

195

using a one-way analysis of variance (ANOVA) method. Significant differences

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between the means (at the level of p 8° palm oil ≈ red palm oil > 24° palm oil. After three months of storage,

360

the OPAH concentration in the palm oils increased more rapidly. This is similar to the 17


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increasing trend of PAH4 and PAH8 concentrations during storage. In contrast, the

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five OPAHs presented much higher concentrations than those of PAH4, and even

363

slightly higher than those of PAH8 at each stage of the storage. Considering the higher

364

toxicity of OPAHs9, 28-30 and the lack of any regulatory limit on OPAH concentrations

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in edible oils, the monitoring of concentrations, the formation mechanism and

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inhibition measures for OPAHs in edible oils demand further study.

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As for the formation of OPAHs, little has been known about the effects of light

368

intensity on the parent PAHs and their oxygenated products in vegetable oils. In this

369

study, there were four pairs of PAH/OPAH: F/9FO, Ant/ATQ, BaA/BaAQ and

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BaP/BaPO. Figure 5 shows the concentration relationships between the four pairs of

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PAH/OPAH. The concentrations of F, Ant and BaP in all the palm oils at 6000 lx were

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significantly higher than those at 0 lx after storage. Correspondingly, the

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concentrations of the three parent PAH oxidized products 9FO, ATQ and BaPO at

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6000 lx were also significantly higher than those at 0 lx after storage. In comparison,

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no significant difference was observed between the effects of 0 lx and 6000 lx on the

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concentration of BaA/BaAQ. This might be due to the difference between the

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absorption spectrum of BaA/BaAQ and the other pairs of PAH/OPAH.

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It is worth reflecting that photodegradation happens under light. This might

379

influence the concentration changes of PAHs and OPAHs during storage. Most

380

previous studies focused on the effect of light intensity on PAH photodegradation in

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water systems. Wu et al. studied the photodegradation kinetics mechanism of three

382

light PAHs (F, Phe and Pyr) in aqueous solution.9 They indicated that the 18



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photodegradation rate of PAHs was related to their absorption spectrum. However, the

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detailed mechanism of photodegradation and photo-oxidation of PAHs in food

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demands further study.

386 387

AUTHOR INFORMATION

388

Corresponding Authors

389 390 391 392

Tel./Fax: +86 21 34205717. E-mail: [email protected]. ORCID Shimin Wu: 0000-0002-2087-6726 Funding

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This study was supported by a grant from the National Natural Science Foundation

394

of China (Nos. 31471668 and 31671958) and SJTU Agri-X Funding (No.

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Agri-X2015007).

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Notes

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The authors declare no competing financial interest.

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485

(29) Kawanaka, Y.; Matsumoto, E.; Wang, N.; Yun, S.-J.; Sakamoto, K. Contribution

of

polycyclic

aromatic

hydrocarbons

23


(benzo[a]pyrene,

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of nitrated polycyclic aromatic hydrocarbons to the mutagenicity of ultrafine particles

487

in the roadside atmosphere. Atmos. Environ. 2008, 42, 7423–7428.

488

(30) Walgraeve, C.; Demeestere, K.; Dewulf, J. Oxygenated polycyclic aromatic

489

hydrocarbons in atmospheric particulate matter: Molecular characterization and

490

occurrence. Atmos. Environ. 2010, 44(15), 1831–1846.

24



491

Figure captions

492

Fig. 1. Changes in POV during 12 consecutive months of storage at 4 °C in (A) red

493 494 495 496 497 498 499 500 501

palm oil; (B) 5° palm oil; (C) 8° palm oil; (D) 24° palm oil. Fig. 2. Changes in AV during 12 consecutive months of storage at 4 °C in (A) red palm oil; (B) 5° palm oil; (C) 8° palm oil; (D) 24° palm oil. Fig. 3. Concentrations of total 16 PAHs before and after storage in red palm oil, 5° palm oil, 8° palm oil and 24° palm oil. Fig. 4. Ring distribution characteristics of PAHs before and after storage in (A) red palm oil; (B) 5° palm oil; (C) 8° palm oil; (D) 24° palm oil. Fig. 5. Concentrations of four pairs of PAHs and OPAHs before and after 12 consecutive months of storage at 4 °C in red palm oil at 0 and 6000 lx.

25


Page 26 of 34

Page 27 of 34


Table 1 LOD, LOQ, regression equation and average recovery of 16 PAHs and five OPAHs. PAHs &

LOD (µg/kg)

LOQ (µg/kg)

Regression equation

Average recovery (%)

NA

0.0240

0.0800

y = 563.11 x + 1165

71.12

Ap

0.0206

0.0687

y = 503.17 x + 16.97

72.07

Ac

0.0279

0.0930

y = 296.31 x + 141.52

72.94

F

0.0377

0.1256

y = 338.00 x + 212.87

72.17

OPAHs

Phe

0.0262

0.0872

y = 421.38 x + 679.23

86.68

Ant

0.0943

0.3145

y = 367.82 x - 313.56

81.69

Fl

0.0218

0.0728

y = 373.09 x - 67.656

91.03

Pyr

0.0932

0.3106

y = 384.16 x + 68.181

108.08

BaA

0.0166

0.0555

y = 208.63 x - 35.040

78.95

Chr

0.0711

0.2371

y = 243.34 x - 170.99

96.89

BbF

0.0082

0.0272

y = 236.29 x + 77.147

99.48

BkF

0.0711

0.2370

y = 228.51 x - 282.15

99.34

BaP

0.0513

0.1709

y = 237.43 x - 184.43

75.02

Ip

0.0272

0.0906

y = 275.74 x - 178.58

105.13

DBahA

0.0369

0.1232

y = 271.87 x - 330.97

105.64

BghiP

0.0602

0.2006

y = 295.77 x + 79.970

103.52

9FO

0.0422

0.1406

y = 337.97 x + 367.74

81.26

ATQ

0.1187

0.3956

y = 107.50 x + 277.88

83.18

BZA

0.1763

0.5875

y = 72.989 x + 347.04

85.65

BaAQ

0.2351

0.7837

y = 38.754 x + 91.462

99.03

BaPO

0.1572

0.5241

y = 39.254 x + 53.328

100.97

26



Page 28 of 34

Table 2 4-HNE and 4-HHE concentrations in the four palm oils during 12 consecutive months of storage at 4 °C (µg/kg). Storage

Concentrations of 4-HNE (µg/kg)

time (month) 0

Red palm oil 0 lx 29.21±5.40

600 lx Aa Ca

1

65.53±5.83

3

54.67±1.99Ba

6

80.28±9.90Da Ea

5° Palm oil 6000 lx

29.21±5.40

Aa

68.30±4.87

Ba

29.21±5.40

0 lx Aa Bb

36.38±7.02

600 lx Aa Bb


Aa

36.38±7.02

Bd

36.38±7.02

0 lx Aa Bh

101.42±9.27

101.42±9.27

162.36±3.60

510.63±19.82

71.85±2.09Bb

102.9±9.50Bc

146.33±2.24Ce

314.51±7.60Ci

954.13±4.27Ck

123.66±5.17Cb

249.26±6.32Cf

158.35±6.59Dd

560.01±8.70Di

1357.50±10.67Dk

Da

De

Ec

Eh

9

129.72±5.15

135.48±3.24

12

149.85±2.86Fa

170.65±1.14Eb

300.78±7.35

454.64±8.18Ef

Ej

600 lx

38.17±9.73

Aa

71.85±2.09

Ba

38.17±9.73


Aa Be

38.17±9.73

0 lx Aa Bf

31.61±9.34

600 lx Aa Ba

6000 lx

31.61±9.34

Aa

142.67±9.02

391.85±6.01Cg

213.82±5.91

282.03±7.71

65.53±5.83

158.35±6.59Cf

279.18±9.72Ch

356.79±1.62Cj

129.72±5.15Cd

205.69±7.03Cg

282.03±7.71Bh

170.65±1.14De

356.79±1.62Dg

752.05±2.49Dj

146.33±2.24Dc

242.23±3.71Df

459.38±8.92Dh

Ed

Eg

Ei

Eb

Ef

259.78±5.57

593.42±1.83

1790.69±0.74

279.18±9.72

454.64±8.18

851.22±8.97

162.36±3.60

376.7±3.14

300.78±7.35Fd

851.22±8.97Fh

2062.09±6.78Fk

391.85±6.01Fe

515.94±5.76Fg

1537.74±9.91Fj

241.21±1.08Fc

456.51±7.73Ff

Storage

31.61±9.34Aa

Bc

858.94±7.37Ei 1298.17±56.71Fi

Concentrations of 4-HHE (µg/kg)

time

Red palm oil

5° Palm oil

8° Palm oil

24° Palm oil

(month)

0 lx

600 lx

6000 lx

0 lx

600 lx

6000 lx

0 lx

600 lx

6000 lx

0 lx

600 lx

6000 lx

0

2.49±0.07Aa

2.49±0.07Aa

2.49±0.07Aa

6.62±1.85Ac

6.62±1.85Ac

6.62±1.85Ac

2.25±1.13Aa

2.25±1.13Aa

2.25±1.13Aa

3.38±1.13Bb

3.38±1.13Ab

3.38±1.13Ab

1

6.46±0.47Bb

14.03±0.21Bd

20.92±1.98Be

15.12±1.02Bd

70.64±4.93Bg

103.68±4.57Bh

8.45±4.73Bc

19.05±1.14Be

18.9±2.85Be

n.d.Aa

17.86±4.22Be

38.00±4.17Bf

3

9.67±0.92Cc

24.9±0.65Cd

70.74±4.09Cg

23.99±2.12Cd

73.68±4.57Bg

123.49±10.95Ch

7.68±0.42Ba

22.55±4.96Bd

61.48±4.06Df

8.2±0.76Cb

27.58±1.50Ce

71.02±4.48Cg

6

14.03±0.21Da

35.81±2.53Dd

71.02±4.48Cf

25.58±1.50Cc

81.06±4.09Ch

135.39±4.04Di

18.87±2.01Cb

40.80±4.00Ce

55.44±3.36Cf

16.80±1.17Db

22.55±4.96Cc

70.73±4.94Cg

9

20.92±1.98

Ea

Db

Df

Dc

Dc

De

Ea

Dd

12

24.90±0.65Fa

36.09±4.27

41.06±4.09Ec

85.84±0.04

88.15±3.82Eg

43.86±0.96

68.04±3.13Ef

Dg

Eh

117.76±1.79

170.6±2.74

170.64±4.93Ej

284.22±4.07Fk

18.9±2.85

Ca

33.49±4.24Db

Different lowercase letters within a row represent significant differences (p < 0.05). Different capital letters within a column represent significant differences (p < 0.05).

27


43.86±0.96

70.35±4.25Ef

68.04±3.13

160.09±4.30Ei

22.35±1.05

44.96±2.32Fc

55.44±3.36

62.70±4.48Ee

123.49±10.95Dg 135.39±4.04Eh

Page 29 of 34


Table 3 PAH4, PAH8 and OPAH concentrations in the four palm oils during 12 consecutive months of storage at 4 °C (µg/kg). Storage

Concentrations of PAH4 (µg/kg)

time (month)

Red Palm oil 0 lx

600 lx


4.36±0.52Bb

4.63±0.55Bc

4.08±0.43Ca

4.35±0.53Bb

4.95±0.59Cd

4.36±0.52Ab

4.95±0.59Bd

5.88±0.62Bf

5.22±0.53Be

5.63±0.62Bf

5.74±0.62Bf

6

6.18±0.63

Cb

Cc

Dc

Ce

De

5.29±0.62

Ba

6.79±0.72

Cc

Cd

Cc

7.24±0.76

Bd

8.06±0.89Ce

8.64±0.93

Dc

7.28±0.82

Ca

8.63±0.89

Dc

8.93±0.95

Cd

9.71±1.06De

9

7.03±0.80

12

9.18±0.92Ea

10.27±1.09Eb

9.37±0.99

Dd

11.32±1.17Ec

6.46±0.66

Ec

3.43±0.42

Aa

7.94±0.85

3.00±0.34 4.16±0.48

Bb

8.05±0.85

De

8.40±0.89

9.50±1.01

10.14±1.09

9.98±1.08Fb

11.31±1.17Ec

Storage

Ef

13.07±1.37Fe

4.02±0.43 4.10±0.47

Ab

9.26±0.93Da

4.02±0.43 4.00±0.44

Ab

10.28±1.05Eb

4.02±0.43

4.44±0.50

7.50±0.78 9.20±0.97

Ac

Dd

12.35±1.32Ed

4.43±0.50

Ab

6000 lx

Ca

6.58±0.74

3.00±0.34

Ab

600 lx

3.98±0.42Ba

3.61±0.43

Ba

Ab

0 lx

3

4.26±0.45

3.00±0.34

Ab


3.64±0.43

Bc

Aa

600 lx

1

3.44±0.39

Aa

0 lx

Aa

Da

4.07±0.50

Bb

Aa


3.44±0.39

5.51±0.63

3.44±0.39

Aa

600 lx

Aa

0

Aa

0 lx

4.30±0.48

Ac

6.68±0.72 7.52±0.78

Db

9.34±1.02Ea

4.43±0.50

Ab

4.43±0.50Ab

4.16±0.47

Ab

4.87±0.57Ad

10.03±1.09Db

11.30±1.20Ec

Concentrations of PAH8 (µg/kg)

time

Red Palm oil

5° Palm oil

8° Palm oil

24° Palm oil

(month)

0 lx

600 lx

6000 lx

0 lx

600 lx

6000 lx

0 lx

600 lx

6000 lx

0 lx

600 lx

6000 lx

0

6.06±0.36Aa

6.06±0.40Aa

6.06±0.39Aa

5.79±0.31Aa

5.79±0.31Aa

5.79±0.39Aa

6.85±0.43Ac

6.85±0.45Ac

6.85±0.43Ac

6.47±0.49Ab

6.47±0.53Ab

6.47±0.46Ab

1

7.84±0.37Bb

8.18±0.45Bc

8.72±0.52Bd

7.67±0.45Bb

7.83±0.40Bb

8.05±0.45Bc

7.69±0.41Bb

7.95±0.40Bb

8.56±0.52Bd

7.30±0.50Ba

7.69±0.46Bb

7.90±0.56Bb

3

9.29±0.41

Cb

Ca

Cc

Cb

Cc

Cc

Ca

Ca

8.93±0.64Cb

6

11.69±0.57Dc

12.34±0.64Dd

13.44±0.68De

10.02±0.67Da

13.14±0.83De

14.47±0.88Df

10.48±0.56Db

11.88±0.78Dc

12.04±0.80Dc

9

Ed

Ee

Ef

13.76±0.92

Ec

Ef

Eg

Eb

13.42±0.94

Ec

13.38±0.92

Ec

17.28±1.06

Fd

17.82±1.10

Fd

17.79±1.31

Fd

12

14.28±0.78

17.49±1.00

Fd

10.41±0.44

Cd

15.76±0.95

18.40±1.06

Fe

10.99±0.53

Ce

16.54±1.01 19.03±1.21

Fe

8.47±0.45

9.79±0.49

16.64±1.20

20.89±1.17

10.09±0.57

Ff

18.53±1.09

Cc

23.70±1.35

Storage

Fg

8.96±0.47

12.40±0.75

16.74±0.96

9.90±0.54

Fc

9.72±0.66

8.41±0.55

9.83±0.71Da 11.76±0.83

Ea Fa

14.93±0.95

8.53±0.65

10.04±0.76Da

10.56±0.86Db

Eb

12.72±0.98Eb

Fa

15.49±1.22Fb

12.31±0.93

15.24±1.08

Concentrations of total OPAHs (µg/kg)

time

Red Palm oil

5° Palm oil

8° Palm oil

24° Palm oil

(month)

0 lx

600 lx

6000 lx

0 lx

600 lx

6000 lx

0 lx

600 lx

6000 lx

0 lx

600 lx

6000 lx

0

8.15±1.57Bb

8.15±1.57Bb

8.15±1.57Ab

8.90±0.86Bc

8.90±0.86Ac

8.90±0.86Ac

7.42±0.92Ba

7.42±0.92Aa

7.42±0.92Aa

8.11±1.05Ab

8.11±1.05Ab

8.11±1.05Ab

1

8.18±1.38Bb

8.03±0.61Bb

8.25±1.42Ac

8.76±1.44Bd

9.54±1.77Be

9.32±1.29Be

7.27±1.06Aa

7.78±0.71Bb

7.22±1.04Aa

8.02±1.02Ab

8.00±1.07Ab

8.92±1.40Bd

3

7.50±0.92

Aa

Aa

9.54±1.47

Be

Ab

8.68±2.07

Ac

Ba

7.91±1.65

Bb

Cc

Ab

Ab

8.74±1.37Bc

6

8.06±1.49

Bb

9.91±1.70

Be

9.28±1.55

Bd

7.46±1.52

Aa

Bf

9.94±0.80Ce

9

15.38±1.45Cd

16.70±1.60Ef

16.18±1.35Ce

13.47±1.57Cb

13.53±0.76Cb

17.06±1.25Eg

13.66±1.02Cb

13.90±1.41Cb

16.83±1.54Ef

12.26±1.36Ca

14.19±0.60Cc

15.80±1.18De

De

Db

Di

Dd

Dd

Fg

Dc

Df

Fh

Ca

De

23.11±1.45Eh

12

17.79±1.53

7.32±1.04

8.68±1.50

Cc

13.56±1.19

24.41±1.77

8.25±0.76

8.99±1.55

Bd

15.91±2.45

15.64±2.42

11.19±0.64

Df

10.58±1.26

19.77±2.06

Cf

7.78±1.52 7.35±1.33

Aa

14.07±1.42

Different lowercase letters within a row represent significant differences (p < 0.05). Different capital letters within a column represent significant differences (p < 0.05).

28


18.90±1.81

8.67±1.87 9.71±1.22

De

23.77±1.66

8.31±1.17

8.46±1.28

Bc

12.78±1.95

8.44±1.60

10.38±0.86

17.96±2.05


Fig. 1

29


Page 30 of 34

Page 31 of 34


Fig. 2

30



Fig. 3

31


Page 32 of 34

Page 33 of 34


Fig. 4

32



Fig. 5

27


Page 34 of 34

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