Optimization of Physical Refining Process of Camellia Oil for Reduction of 3-Monochloropropane-1,2-Diol (3-MCPD) Ester Formation Using Response Surface Methodology on a Laboratory Scale.

Refined and deodorized camellia oil has been reported to contain a high amount of 3-monochloropropane-1,2-diol esters (3-MCPDE) due to the high-temperature deodorization step. To reduce 3-MCPDE in camellia oil, the physical refining process of camellia oil was simulated on a laboratory scale. Response surface methodology (RSM) was designed to modify and optimize the refining process with five processing parameters (water degumming dosage, degumming temperature, activated clay dosage, deodorization temperature and deodorization time). The optimized new refining approach achieved a 76.9% reduction in 3-MCPDE contents, in which the degumming moisture was 2.97%, the degumming temperature was 50.5 °C, the activated clay dosage was 2.69%, the deodorizing temperature was 230 °C, and the deodorizing time was 90 min. A significance test and analysis of variance results demonstrated that the deodorization temperature and deodorization time contributed significantly to the reduction of 3-MCPD ester. The joint interaction effects of activated clay dosage and deodorization temperature were significant for 3-MCPD ester formation.

Spatial analysis of dietary exposure of aflatoxins in peanuts and peanut oil in different areas of China.

Peanuts in China are heavily contaminated with aflatoxin, which pose a threaten to human health. To compare the dietary exposure risk of aflatoxins (AFT) in peanuts and peanut oil in different areas of China, the spatial distribution of AFT contamination levels in peanuts and peanut oil from different areas was analyzed. The dietary exposure was calculated by simple distributed risk assessment method before characterizing the health risk using both the margin of exposure (MOE) approach proposed by the European Food Safety Authority (EFSA) and the quantitative liver cancer risk approach proposed by the Joint Food and Agricultural Organization/World Health Organization (FAO/WHO) Expert Committee on Food Additives (JECFA). The results showed that the AFT content in peanuts and peanut oil was high with agglomeration in several provinces of East and South China under a subtropical temperate monsoon climate, and the AFT contamination in peanut oil was more substantial than peanuts. On average, the estimated dietary exposure to AFT from the total of peanuts and peanut oil for Chinese general population ranged from 1.776 to 1.940 ng/kg bw/day (LB-UB), from which the MOE values of 88-96 (UB-LB) and liver cancer risk of 0.055-0.060 cases/100,000 persons/year (LB-UB) were calculated. As for different areas in China, the mean AFT exposure ranged between 0.000 and 17.270 ng/kg bw/day. Moreover, the corresponding health risk was estimated at 10-868759 MOE values and 0.000-0.851 liver cancer cases/100,000 persons/year. Guangdong, Fujian and Jiangxi provinces were at a higher risk rank. The liver cancer risk of AFT exposure from peanuts and peanut oil was far below all-cause liver cancer incidence (18.0 cases/100,000 persons/year) in China, but several areas with relatively high risk should be of concern. Compared with other age groups, children aged 2-6 years should be paid more attention because they have the highest AFT exposure level.

Dietary exposure of general Chinese population to fatty acid esters of 3-monochloropropane-1, 2-diol (3-MCPD) from edible oils and oil-containing foods.

Edible oils and oil-containing foods have been regarded as the main source of 3-monochloropropane-1, 2-diol (3-MCPD) esters. A total of 3,847 individual food samples were collected in China to carry out 3-MCPD fatty acid esters analysis. The samples comprising edible oils, fried foods and bakery foods from 31 Chinese provinces, municipalities and autonomous regions were obtained from the national food contaminant information system during 2015-2017. The dietary exposure and potential risks associated with the consumption of 3-MPCD esters from edible oils and oil-containing foods were estimated using a semi-probabilistic assessment model. Concentrations of 3-MCPD fatty acid esters in food samples were detected by gas chromatography-mass spectrometry (GC-MS). The mean levels of 3-MCPD fatty acid esters in edible oils, fried foods and bakery foods were 0.862, 0.249 and 0.145 mg/kg, respectively. The range of mean dietary intakes of 3-MCPD esters in different subpopulation groups (classified by gender and age) was from 0.586 to 1.539 µg/kg bw/day, which were all lower than 2 µg/kg bw/day - the tolerable daily intake (TDI) established by the European Food Safety Authority (EFSA). The range of dietary intake of 3-MCPD esters in high consumers (95th percentile) in each group was from 1.511 to 4.027 µg/kg bw/day, which accounted for 75.6% to 201.4% of the TDI. The 3-MCPD esters exposure level of 3.5% of the total Chinese population exceeded the TDI. The findings indicate that the potential health risks caused by dietary 3-MCPD esters from edible oils and oil-containing foods were of low concern for most of the Chinese population. However, the exposure risk of the consumers with excessive edible oil consumption calls for attention.

Dietary cadmium exposure assessment among the Chinese population.

Cadmium, a toxic heavy metal, is widely present in food. It has been reported that chronic cadmium exposure is associated with kidney disease, osteoporosis, cardiovascular disease and cancer. The aim of this study was to assess the dietary cadmium exposure and potential health risk in different age-sex groups of the Chinese population (children aged 4-11 years, young people aged 12-17 years and adults aged over 18 years), and in the southern and northern population using a semi-probabilistic method. Cadmium was detected in 228,687 food samples from 32 food categrories by graphite furnace atomic absorption spectrometry. The dietary cadmium exposures were estimated by combining the cadmium concentration data with food consumption data derived from the China National Nutrient and Health Survey 2002, and evaluated against the Provisional Tolerable Monthly Intake (PTMI) of 25 µg/kg BW/month established by the Joint FAO/WHO expert committee on food additives (JECFA). The mean dietary cadmium exposure of the general Chinese population (15.3 µg/kg BW/month) was below the PTMI. The high consumer exposures (95th percentile, P95) for the general population and different sub-groups were higher than the PTMI. The dietary cadmium exposure of the southern population was apparently higher than that of the northern population. Rice was the most important contributor to cadmium exposure for Chinese people, especially those living in the southern areas of China. These findings indicated that the health risk from dietary cadmium exposure of the general Chinese people was low, but the health risk of cadmium exposure of certain sub-groups should be of concern.

Isotope dilution gas chromatography with mass spectrometry for the analysis of 4-octyl phenol, 4-nonylphenol, and bisphenol A in vegetable oils.

By the combination of solid-phase extraction as well as isotope dilution gas chromatography with mass spectrometry, a sensitive and reliable method for the determination of endocrine-disrupting chemicals including bisphenol A, 4-octylphenol, and 4-nonylphenol in vegetable oils was established. The application of a silica/N-(n-propyl)ethylenediamine mixed solid-phase extraction cartridge achieved relatively low matrix effects for bisphenol A, 4-octylphenol, and 4-nonylphenol in vegetable oils. Experiments were designed to evaluate the effects of derivatization, and the extraction parameters were optimized. The estimated limits of detection and quantification for bisphenol A, 4-octylphenol, and 4-nonylphenol were 0.83 and 2.5 µg/kg, respectively. In a spiked experiment in vegetable oils, the recovery of the added bisphenol A was 97.5-110.3%, recovery of the added 4-octylphenol was 64.4-87.4%, and that of 4-nonylphenol was 68.2-89.3%. This sensitive method was then applied to real vegetable oil samples from Zhejiang Province of China, and none of the target compounds were detected.

Determination of three kinds of banned drugs in milk powder by hybrid solid-phase extraction purification combined with gas chromatography and mass spectrometry.

A gradient clean-up method for the quantification of five kinds of banned drugs (two hormones, two sedatives, and one chloramphenicol) in milk powder was developed. We used the combination of solid-phase extraction purification with gas chromatography and mass spectrometry. Milk powder was initially hydrolyzed by ß-glucuronidase/arylsulfatase, and then the hydrolyzed solution was concentrated and purified using a C8 and cation resin solid-phase extraction column. To isolate hormones and chloramphenicol drugs, products from the previous step were diluted with methanol and further purified using a silica and diatomite solid-phase extraction column. After derivatization, the drugs were analyzed by gas chromatography with mass spectrometry, and the hydrolyzed solution was diluted with 5% ammoniated methanol to purify sedatives before gas chromatography with mass spectrometry analysis. Results showed that after adding the banned drugs at concentrations of 0.3-10.0 µg/kg, the average recovery range was 78.2-97.3% with relative standard deviations of 5.3-12.5%. The limit of quantification of the banned drugs (S/N ≥ 10) was 0.3-5.0 µg/kg, whereas the limit of detection (S/N ≥ 3) was 0.1-2.0 µg/kg. The solid-phase extraction gradient purification system was simple, rapid, and accurate, and could satisfy the detection requirements of hormone, sedatives, and chloramphenicol drugs when used together with gas chromatography and mass spectrometry.

Identification of 19 phthalic acid esters in dairy products by gas chromatography with mass spectrometry.

A detection method for 19 kinds of phthalic acid ester compounds analyzed by n-hexane/ether/acetonitrile 1:7:8 v/v/v mixed solvent extraction, quick, easy, cheap, effective, rugged, and safe purification and internal standard method of quantitative gas chromatography with mass spectrometry was established. This method can effectively remove interfering materials, such as lipids, fatty acids, and pigments, from dairy products. The 19 kinds of phthalic acid ester compounds were within a 0.025-0.2 mg/kg range, the recovery rate was 65.2-125.7%, relative standard deviation was 7.9-15.4% (n = 6), and the limit of detection was 0.005-0.02 mg/kg. Concentrations of the 19 kinds of phthalic acid ester compounds ranged between 0.01 and 0.12 mg/kg in ten dairy materials and 20 dairy products. The established method is simple, rapid, accurate, and highly sensitive.

[Comparison and anylisis on national quality control examination results of pesticides residues in food in 2009 and 2011].

OBJECTIVE: To find out and compare the professionals proficiency of monitoring and inspection agencies on pesticide residue in food, and identify the main factors affecting the quality of result to provide references for improving the quality of the monitoring and inspection results. METHODS: Compare the national quality control examination results of pesticides residues in food of 2009 with 2011. RESULTS: The submission rates of examination results in 2011 were much higher than in 2009. They were respectively 100% and 83.6%. With the exception of few pesticides, the qualitative qualification rate and quantitative satisfaction rate of other pesticides were also relatively higher, and the qualitative qualification rate and quantitative satisfaction rate in 2011 were all higher than the same examination pesticides in 2009. For instance, the qualitative qualification rate of chlorpyrifos were respectively 99.4% and 96.8% in 2011 and 2009. The qualitative qualification rate of triazophos were respectively 100% and 97.1% in 2011 and 2009. The quantitative satisfaction rate of chlorpyrifos were respectively 93.8% and 90.2% in 2011 and 2009. The quantitative satisfaction rate of triazophos were respectively 91.9% and 87.2% in 2011 and 2009. CONCLUSION: The general testing levels of monitoring and inspection agencies on pesticide residue in food were sufficient, and their testing proficiency increased year by year, but some institutions still need to improve the testing proficiency.

[Simultaneous determination of three antioxidants BHA, BHT and TBHQ in food by liquid chromatography and gas chromatography].

OBJECTIVE: To develop a method for determining 3 kinds of antioxidants in food in same time with HPLC and GC. METHODS: Firstly, extracted fat with petroleum ether, then extracted antioxidants with 13 ml methnol, centrifuged, repeated the above procedure twice, combined the extracts, next evaporated to 5 ml, constanted volume to 10 ml, then kepted in freezer (- 1h), lastly, the supernatant injected into high performance liquid chromatography (HPLC) and Gas chromatography (GC) which had been optimized condition. RESULTS: The limits of quantitation for BHA,BHT and TBHQ were 0.002, 0.010 and 0.002g/kg respectively in HPLC, The limits of quantitation for BHA, BHT and TBHQ were 0.003, 0.002 and 0.005 g/kg respectively in GC, The mean recoveries at the two spiked levels were 82.8% - 109.0%. There were no significant difference between HPLC and GC. CONCLUSION: The method can be used to determine the antioxidants in food accurately and sensitively, the comparative results are constant between liquid and gas chromatography.

Simultaneous determination of 17 phthalate esters in edible vegetable oils by GC-MS with silica/PSA-mixed solid-phase extraction.

A quantified method for the determination of 17 phthalate esters (PAEs) in edible vegetable oil by GC-MS with the pretreatment of acetonitrile extraction and silica/N-(n-Propyl)ethylenediamine-mixed SPE column was established. By the quantification of internal standard of D(4)-di(2-ethylhexyl) phthalate, a good linearity range of related 17 PAEs was observed. The correlation coefficient was ranged at 0.994~1.000, and the standard lowest quantified level was 0.05~0.15 mg/L. The spiking recoveries of 17 PAEs were 78.3~108.9% with the relative standard deviations of 4.3~12.1% (n = 6). The method detection limits were 0.1~0.2 mg/kg. Meanwhile, PAEs were determined in 30 plastic buckets of edible vegetable oil from supermarkets in Hangzhou city of China. The survey of 30 oil samples showed di(2-ethylhexyl) phthalate (DEHP) had the 100% (30/30) detection rate. The levels of diisobutyl phthalate with 86.7% (26:30), di-n-butyl phthalate (DBP) with 70% (21:30) and diethyl phthalate with 10% (3:30) were detected. It was worth note that DBP with 16.7% (5:30) samples and DEHP with 10% (3:30) samples were beyond the regular migrating limit, which indicated that more attention should be paid to the PAEs in oil with plastic package.

[Quality control examination on testing pesticides residues in food for agencies in charge of food safety risk monitoring and inspection].

OBJECTIVE: To find out the proficiency of professionals in monitoring and inspection agencies on the determination of pesticides residue in food, and to improve the accuracy and comparability of testing results. METHODS: Three sets of quality control samples with the same matrix but different in concentrations of pesticides were prepared; one of blind quality control samples contained chlorpyrifos, methyl parathion, methyl pirimiphos, fenitrothion or triazophos and bifenthrin was dispatched to each inspection agency. Criteria for testing results were evaluated by Z scores: [Z] = < or = 2 for satisfactory; 2 < [Z] < 3 for uncertainty and [Z] > or = 3 for unsatisfactory. RESULTS: The results of all quality control blind samples delivered to 162 agencies were submitted back on time. The qualitative and quantitative qualification rate for chlorpyrifos was 99.4% and 93.8%, for parathion-methyl was 96.3% and 94.9%, for bifenthrin was 95.7% and 89.7%, for fenitrothion was 92.0% and 89.6%, for triazophos was 100% and 91.9%, respectively. CONCLUSION: The general proficiency on tested pesticide residues in food was relatively good for monitoring and inspection agencies. The agency who got unsatisfied results has recognized the problems in the process of testing; the cause of uncertainty and unsatisfactory results were found; and effective corrections were conducted to ensure the accuracy of data in the future.

[The determination of phthalic acid esters in edible vegetable oils by gas chromatography-mass spectrometry].

OBJECTIVE: We aimed to establish a quantified method for the 17 phthalate acid esters (PAE) in edible vegetable oil by gas chromatography-mass spectrometry (GC-MS) with the pretreatment of acetonitrile extraction and silica/N-(n-propyl)ethylenediamine (silica/PSA) mixed solid phase extraction column and evaluated the PAE of 25 edible oil samples from supermarkets in Hangzhou city. METHODS: The internal standard solution (D4-DEHP) was added in edible vegetable oil sample. The analytes were extracted by acetonitrile with 1 min vortex, and centrifuged at 3050×g for 5 min. The supernatant was then cleaned with silica/PSA column, and eluted with acetonitrile. The elution was dried with N2 flow at 50°C and diluted to 1.0 ml with hexane. Then, 17 PAE were tested by GC-MS and quantified with internal standards. The repeatability and sensitivity of the assay were evaluated. PAE were then determined in 25 plastic buckets of edible vegetable oil from supermarkets in Hangzhou city. RESULTS: By the quantification of internal standard of D4-DEHP, a good linearity range of related 17 PAE was observed. The correlation coefficient was 0.994-1.000 and the standard lowest quantified level was 0.05-0.15 µg/ml. The spiking recoveries of 17 PAE were 78.3%-108.9% with the RSD of 4.3%-12.1% (n=6). The method detection limits were 0.1-0.2 mg/kg. In 25 plastic buckets of edible vegetable oil from Hangzhou, DMP, DEP, DIBP, DBP and DEHP were detected at the range of <0.1-1.8 mg/kg and the detection rates were 12% (3/25), 24% (6/25), 100% (25/25), 96% (24/25) and 100% (25/25), respectively. Other 12 PAE was not detected. For DBP with the level of <0.1 to 1.3 mg/kg, the results of 16% (4/25) samples exceeded the regular migrating limit of 0.3 mg/kg. For DEHP of <0.2-1.8 mg/kg, the data of 12% (3/25) samples were beyond the regular migrating limit of 1.5 mg/kg. CONCLUSION: The pretreatment by silica/PSA mixed solid phase extraction column can satisfy the PAE determination requirements in edible vegetable oils. The DMP, DIBP, DEP, DBP and DEHP were detected from the survey of 25 edible oil samples in Hangzhou city.

Study on migration of melamine from food packaging materials on markets.

OBJECTIVES: To study the migration of melamine into foods from plastic food packaging materials and dairy product containers commonly used in China. METHODS: 37 samples were collected from the market. The EU migration testing conditions were adopted with distilled water, 3% acetic acid, n-hexane and 15% ethanol being chosen as the simulating solutions. The HPLC method was used to detect melamine. RESULTS: No melamine was detected in 15 dairy product containers. Among the 22 plastic samples, 16 of polypropylene, and polycarbonate types had no detectable amount melamine while a low level of melamine was found in 3 of the 6 melamine resin containers. CONCLUSION: Migration of melamine from food packaging materials in China market is in line with the requirements of EU.

Use of capillary electrophoresis to evaluate protective effects of methylglyoxal scavengers on the activity of creatine kinase.

Methylglyoxal (MGO) is a highly reactive alpha-oxoaldehyde formed endogenously in numerous enzymatic and nonenzymatic reactions. The reactions between MGO and various amino residues in proteins not only result in inactivation of enzymes, but also lead to the formation of different detrimental advanced glycation endproducts (AGEs). Recently, it was reported that creatine kinase (CK, EC 2.7.3.2) activity could be reduced or even lost under incubation with MGO in vitro. In this study, an efficient CE analytical method was developed for the evaluation of CK activity. Based on this CE method, the inhibitory effect of MGO on CK activity was confirmed. Several MGO scavengers such as aminoguanidine (AG) and some thiols showed obvious protective effects on CK activity against MGO. Furthermore, tiopronin (TP), a hepatoprotective drug, was found for the first time to counteract MGO-induced inhibition of CK activity in CK reaction. Meanwhile, TP also retained adenosine diphosphate (ADP) generation level in plasma treated with MGO, which implies that this drug may have potential protective effect on other enzymes which are associated with adenine nucleotide metabolism. Besides, the established CE approach can be utilized as a model for screening effective MGO scavengers by monitoring CK-catalyzed conversion between adenosine triphosphate and ADP.