A survey of styrene monomer levels in foods and plastic packaging by coupled mass spectrometry—automatic headspace gas chromatography

An extensive UK survey of styrene monomer levels in styrene based plastic packaging materials and their contained foods (133 samples) has been carried out, examining a wide range of retail foods of different brand names and including yogurts, creams, salads, coleslaws, soft cheeses, margarines, hot and cold beverages from dispensing machines, spreads, fresh and cooked meats, candied fruits, fresh strawberries, and take-away ‘fast’ foods. Analysis by headspace gas chromatography of styrene levels in the plastic containers showed levels of monomer ranging from 16 to 1300 mg kg^?1 although the majority of containers (73%) had styrene levels in the range 100–500 mg kg^?1 and only five plastic tubs had levels exceeding 1000 mg kg^?1. Analysis of the food contents of the plastic containers by automated headspace gas chromatography with single ion monitoring mass spectrometric detection showed levels of the monomer ranging from < 1 μg kg^?1 to 200 μg kg^?1, although the majority of foods (77%) had styrene levels below 10 μg kg^?1, and 26% of the total number analysed had levels below 1 μg kg^?1.     

Boron concentrations in selected foods from borate‐producing regions in Turkey

As part of a large‐scale programme to investigate the health effects of exposure to borate minerals in Turkey, boron concentrations in vegetables, fruits and some other foods were determined. From all borate‐producing regions of the country, 22 species of fruit, 17 species of vegetable, 12 species of cereal, legume and oilseed, three species of herbs and six types of other food were collected in 1999 and analysed for boron concentrations using the Azomethine H method. The results were compared with 37 types of food collected from areas well distant from the borate‐producing areas. The total number of samples evaluated was 420. Pistachio (67.0 mg kg^?1) had the highest concentration of boron, followed by grape leaf (60.48 mg kg^?1), sour cherry (57.03 mg kg^?1), quince (38.78 mg kg^?1), peach (34.49 mg kg^?1), grape (20.70 mg kg^?1), green beans (19.49 mg kg^?1), unripe peach (18.92 mg kg^?1) and parsley (10.24 mg kg^?1) from the borate‐producing regions. A large number of foods contained boron at higher concentrations than those reported in the literature, most probably due to the high boron content of these Turkish soils. According to the results of t‐tests, the area itself does not have a significant effect (p > 0.05) on boron concentration in all foods evaluated so far. Copyright © 2003 Society of Chemical Industry     

Effect of substituting fresh‐cut perennial ryegrass with fresh‐cut white clover on bovine milk fatty acid profile

BACKGROUND

Including forage legumes in dairy systems can help address increasing environmental/economic concerns about perennial ryegrass monoculture pastures. This work investigated the effect of substituting fresh‐cut grass with increasing quantities of fresh‐cut white clover (WC) on milk fatty acid (FA) profile and transfer efficiency of dietary linoleic (LA) and α‐linolenic (ALNA) acids to milk fat. Three groups of three crossbred dairy cows were used in a 3 × 3 crossover design. Dietary treatments were 0 g kg^?1 WC + 600 g kg^?1 grass, 200 g kg^?1 WC + 400 g kg^?1 grass, and 400 g kg^?1 WC + 200 g kg^?1 grass. All treatments were supplemented with 400 g kg^?1 concentrates on a dry matter basis. Cows had a 19‐day adaptation period to the experimental diet before a 6‐day measurement period in individual tie stalls.

RESULTS

Increasing dietary WC did not affect dry matter intake, milk yield or milk concentrations of fat, protein or lactose. Milk polyunsaturated FA concentrations (total n‐3, total n‐6, LA and ALNA) and transfer efficiency of LA and ALNA were increased with increasing dietary WC supply.

CONCLUSION

Inclusion of WC in pastures may increase concentrations of nutritionally beneficial FA, without influencing milk yield and basic composition, but any implications on human health cannot be drawn. © 2018 The Authors. Journal of the Science of Food and Agriculture published by JohnWiley & Sons Ltd on behalf of Society of Chemical Industry.

     

Production of maize–bambara groundnut complementary foods fortified pre‐fermentation with processed foods rich in calcium,iron, zinc and provitamin A

BACKGROUND: Maize–bambara groundnut complementary foods are deficient in calcium, iron, zinc and vitamin A. Food‐to‐food fortification could be cheaper, safer and more easily adopted by local communities compared to the use of chemically pure compounds and vitamins to enrich such foods. RESULTS: Maize–bambara groundnut complementary foods fortified for iron, zinc, calcium and vitamin A by blending with a multi‐mix (1.41:1:2.25, w/w) of processed roselle calyces, cattle bones, and red palm oil in a 1:2.1 (w/w) ratio showed significant increases in calcium, iron, zinc and vitamin A contents of 3.26–4.225, 0.083–0.134 and 0.015–0.017 g kg^?1 and 4855.3–7493.7 µgRE kg^?1, respectively. CONCLUSION: The maize–bambara groundnut foods had calcium, iron, zinc and vitamin A contents that satisfy the proposed nutrient requirements for infants. Only the maize–bambara groundnut and maize–bambara groundnut malt fermented by backslopping [(MB)_b and (MB_m)_b] containing red palm oil emulsified with Brachystegia eurycoma had calcium contents significantly (P < 0.05) higher than Nutrend, a complementary food produced by Nestle (Nigeria) PLC. These products are from raw materials produced in commercial quantities by rural farmers using household level technologies which the rural and urban poor can more easily access in order to reduce micronutrient malnutrition. Copyright © 2010 Society of Chemical Industry     

Effect of cross‐linking on some properties of potato (Solanum tuberosum L.) starches

Starches separated from different potato cultivars were modified using two different cross‐linking agents: epichlorohydrin (EPI) and phosphoryl chloride (POCl₃) at different concentrations (1.0 and 2.0 g kg^?1 POCl₃; 2.5, 5.0 and 10 g kg^?1 EPI). Differential scanning calorimetry, rheological and retrogradation measurements were performed to characterise the influence of cross‐linking on the properties of potato starches. Cross‐linking considerably reduced swelling power, solubility, water‐binding capacity and paste clarity. The decrease became greater as the reagent concentration increased. The starches treated with 1.0 g kg^?1 POCl₃ exhibited exceptionally higher swelling power than their counterpart native starches. Neither cross‐linking agent caused any change in morphology of the starch granules. Studies on the phase transitions associated with the gelatinisation showed significantly higher values for the onset temperature (T_o), peak temperature (T_p), conclusion temperature (T_c) and enthalpy of gelatinisation (ΔH_gel) for the cross‐linked starches than the native starches. Starches treated with both the reagents showed lower peak storage modulus (G′) and loss modulus (G″) than their native counterparts. The tendency of the starch pastes towards retrogradation increased considerably with increases in storage duration. However, the starches treated with 1 g kg^?1 POCl₃ exhibited much lower syneresis than the other cross‐linked starches. Copyright © 2006 Society of Chemical Industry     

Suppression of blood glucose level by a new fermented tea obtained by tea‐rolling processing of loquat (Eriobotrya japonica) and green tea leaves in disaccharide‐loaded Sprague‐Dawley rats

BACKGROUND: In the field of food science, much interest has been focused on the development of alternative medicinal foods with the ability to regulate excess blood glucose level (BGL) rise. The authors have successfully developed a new fermented tea product (LG tea) by co‐fermentation of loquat (Eriobotrya japonica) leaf and summer‐harvested green tea leaf. The objective of this study was to examine the acute suppression effect of LG tea on BGL rise in disaccharide‐loaded Sprague‐Dawley (SD) rats and to evaluate its possible usage as an antidiabetic functional food material. RESULTS: As a result of single oral administration of hot water extract of LG tea (50 mg kg^?1) to maltose‐loaded SD rats, BGL at 30 min was significantly decreased by 23.8% (P < 0.01) compared with the control. A corresponding reduction in serum insulin secretion was also observed. The ED₅₀ value of LG tea (50.7 mg kg^?1) was estimated to be about 16‐fold higher than that of the therapeutic drug acarbose (3.1 mg kg^?1). CONCLUSION: No significant change in BGL was observed when sucrose or glucose was administered, suggesting that the suppression effect of LG tea was achieved by maltase inhibition, not by sucrase inhibition or glucose transport inhibition at the intestinal membrane. Copyright © 2010 Society of Chemical Industry     

Microwave‐assisted extraction of secoisolariciresinol diglucoside from flaxseed hull

Microwave‐assisted extraction (MAE) of secoisolariciresinol diglucoside (SDG) from defatted flaxseed hull (DFH) was studied. The effects of pre‐soaking methods and extraction parameters (ethanol concentration (0–100%, v/v), microwave energy input (50–390 W), liquid to solid ratio (5:1 to 40:1, mL g^?1) and irradiation time (10–330 s)) on the SDG yield were investigated. Response surface methodology (RSM) was applied to optimise the MAE conditions as irradiation time 90.5 s, ethanol concentration 40.9% (v/v), liquid to solid ratio 21.9:1 (mL g^?1) and microwave power 130 W. The SDG recovery from DFH with MAE was 11.7 g SECO kg^?1 DFH (on dry‐weight basis), which was significantly higher than that of stirring extraction (10.0 g SECO kg^?1 DFH) and Soxhlet extraction (7.60 g SECO kg^?1 DFH). Compared with stirring extraction and Soxhlet extraction, MAE showed its superiority in improving SDG yield and saving time and energy. Copyright © 2007 Society of Chemical Industry     

Broad bean and pea by‐products as sources of fibre‐rich ingredients: potential antioxidant activity measured in vitro

BACKGROUND By‐products generated during the processing of plant food can be considered a promising source of dietary fibre as a functional compound. The dietary fibre composition, soluble sugars and antioxidant activity of the extractable polyphenols of pea and broad bean by‐products have been analysed in this study. RESULTS: Total dietary fibre using AOAC methods plus hydrolysis (broad bean pod: 337.3 g kg^?1; pea pod: 472.6 g kg^?1) is higher (P < 0.05) in both by‐products than with the Englyst method (broad bean pod: 309.7 g kg^?1; pea pod: 434.6 g kg^?1). The main monomers are uronic acids, glucose, arabinose and galactose in broad bean pods. However, pea pods are very rich in glucose and xylose. The soluble sugars analysed by high‐performance liquid chromatography in both by‐products have glucose as the most important component, followed by sucrose and fructose. The ferric reducing antioxidant power (broad bean pod: 406.4 µmol Trolox equivalents g^?1; pea pod: 25.9 µmol Trolox equivalents g^?1) and scavenging effect on 2,2‐diphenyl‐1‐picrylhydrazyl radical (EC₅₀ of broad bean pod: 0.4 mg mL^?1; EC₅₀ of pea pod: 16.0 mg mL^?1) were also measured. CONCLUSIONS: Broad bean and pea by‐products are very rich in dietary fibre, particularly insoluble dietary fibre and their extractable polyphenols demonstrate antioxidant activity. Therefore they might be regarded as functional ingredients. Copyright © 2011 Society of Chemical Industry     

Quality characteristics of a non‐fermented dry‐cured sausage formulated with lemon albedo

Dry‐cured sausages were treated with two types of dehydrated lemon albedo (raw and cooked) at five concentrations (0–100 g kg^?1 in 25 g kg^?1 increments). Several physical and chemical analyses were made during the drying stage, and compositional, textural and sensory analyses were conducted on the finished products. The addition of albedo improved the nutritional properties as a result of fibre addition and may have beneficial effects due to the presence of active biocompounds as evidenced by a decrease in residual nitrite levels and delayed oxidation (based on TBARS values). The sensory properties of samples that resembled the control sausages were those that contained up to 50 g kg^?1 dehydrated raw albedo and 75 g kg^?1 dehydrated cooked albedo. Copyright © 2004 Society of Chemical Industry     

Assessment of iron bioavailability from twenty elite late‐maturing tropical maize varieties using an in vitro digestion/Caco‐2 cell model

An in vitro digestion/Caco‐2 cell model was used to assess iron bioavailability of twenty elite late‐maturing tropical maize varieties grown in three diverse agroecologies in West and Central Africa (WCA). Kernel‐iron concentration of the varieties, averaged across locations, varied from 19.2 to 24.4 mg kg^?1, while mean kernel‐zinc concentration ranged between 19.4 and 24.6 mg kg^?1. Significant differences in iron bioavailability were observed among varieties, but the environment had no significant effect. Mean bioavailable iron ranged between 14% below and 43% above the reference control variety, TZB‐SR. Variety DMR‐LSR‐Y with the highest concentrations of kernel‐iron and ‐zinc of 24–25 mg kg^?1 across the three locations had a similar quantity of bioavailable iron as the reference control, TZB‐SR. In the long run this variety could be potentially effective in reducing iron deficiency because of its high kernel‐iron. The most promising varieties were Mid‐altitude STR synthetic and ACR91SUWAN‐1‐SRC1. They had kernel‐iron and ‐zinc levels of 22–24 mg kg^?1 and bioavailable iron 24–36% higher than the reference control, TZB‐SR. Additional research is necessary to determine if the increases in kernel‐iron concentration and bioavailable iron observed in this study can significantly improve the iron status of individuals in WCA at risk for iron deficiency. Copyright © 2004 Society of Chemical Industry     

Occurrence of furan in commercial processed foods in Brazil

Selected commercial processed foods available in the Brazilian market (306 samples) were analysed for furan content using a validated gas chromatography-mass spectrometry method preceded by headspace solid phase micro-extraction (HS-SPME-GC/MS). Canned and jarred foods, including vegetable, meat, fruit and sweet products, showed levels up to 32.8?µg?kg^?1, with the highest concentrations observed in vegetables and meats. For coffee, furan content ranged from 253.0 to 5021.4?µg?kg^?1 in the roasted ground coffee and from not detected to 156.6?µg?kg^?1 in the beverage. For sauces, levels up to 138.1?µg?kg^?1 were found. In cereal-based products, the highest concentrations (up to 191.3?µg?kg^?1) were observed in breakfast cereal (corn flakes), cracker (cream crackers) and biscuit (wafer). In general, these results are comparable with those reported in other countries and will be useful for a preliminary estimate of the furan dietary intake in Brazil.     

Headspace analysis of laboratory samples of potato tubers treated with 1,4-dimethylnaphthalene,carvone, pulegone and citral

1,4-Dimethylnaphthalene, carvone [2-methyl-5-(1-methylethenyl)-2-cyclohexene-1-one], pulegone [5-methyl-2-(1-methylethylidene) cyclohexanone] and citral (3,7-dimethyl-2,6-octadienal) were applied as liquids on an alumina solid carrier to samples of potato tubers stored in boxes. The headspace concentrations of the chemicals were related to the degree of growth regulation found in this and earlier solid carrier application experiments and were compared to studies using constant vapour concentration applications which had been conducted previously by other workers. Headspace concentrations of all four chemicals increased with increasing application rates indicating non-ideal behaviour. Pulegone (100 mg kg^?1), carvone (100 mg kg^?1) and citral (100 and 500 mg kg^?1) did not prevent sprouting. Headspace concentrations of these treatments were less than the constant vapour concentrations previously shown to inhibit sprouting. Pulegone (500 mg kg^?1) and carvone (500 mg kg^?1) successfully inhibited sprouting. Initial headspace concentrations of these treatments were within the constant vapour concentration range previously shown to prevent sprouting. Headspace concentrations of all four chemicals decreased during the 14-week treatment period. Headspace concentrations of 1,4-dimethylnaphthalene, when applied at the recommended solid carrier application rate of 100 mg kg^?1 were within the constant vapour concentration range previously shown to prevent sprouting. Headspace concentrations of 1,4-dimethylnaphthalene between 3 and 6 mg m³ would be necessary if the chemical were to be successfully applied as a vapour. For these experiments a gas chromatographic (g.c.) analytical method using porous polymer adsorbents was developed. The method was rapid, with a coefficient of variation of 5%.     

Soil and vegetable compositional relationships of eight potentially toxic metals in urban garden fields from northern Nigeria

BACKGROUND: Human exposure to heavy metals is attributed to consumption of vegetables raised in polluted soil environment. We examined the concentrations of As, Cd, Co, Cr, Cu, Ni, Pb and Zn in soils and lettuce (Latuca sativa) and amaranthus (Amaranthus caudatus) in 15 garden fields under long‐term wastewater irrigation. RESULTS: The concentrations of As (0.3–2.1 mg kg^?1), Cd (0.07–0.3 mg kg^?1), Co (4.6–9.1 mg kg^?1) and Cr (21.6–36.2 mg kg^?1) in the gardens were consistent with background concentrations in soils, but Ni (12.6–25.7 mg kg^?1), Cu (12.5–24.6 mg kg^?1), Pb (25.7–71.6 mg kg^?1) and Zn (52.3–158 mg kg^?1) concentrations were double the concentrations normally encountered in arable fields in the region. The concentrations of Cd and As in the vegetables were within safe limits, but Co (0.14–0.67 mg kg^?1 fresh weight (fw)) and Ni (1.0–2.7 mg kg^?1 fw) concentrations in lettuce were relatively high for leaf vegetables. The concentration of Pb (0.65–4.80 mg kg^?1 fw) was above safe limit of 0.3 mg kg^?1 fw, while the concentrations of Cu (1.3–2.7 mg kg^?1 fw and Zn (10.2–23.6 mg kg^?1 fw) were close to the unsafe limits for leaf vegetables. There were no strong linear correlations between soil metal concentrations and bio‐concentrations in the vegetable crops. CONCLUSION: We surmise that leaf vegetables can accumulate metals in their tissues to unsafe levels even when total metal concentrations in these soils are below the allowable concentrations in agricultural soils. Copyright © 2008 Society of Chemical Industry     

Isotope dilution-GC-MS/MS analysis of 16 polycyclic aromatic hydrocarbons in selected medicinal herbs used as health food additives

Medicinal herbs have a very important role in health protection and disease control, and have been used in health foods. Polycyclic aromatic hydrocarbons (PAHs) have carcinogenic, biological and mutagenic effects. In this paper, the content of 16?PAHs as representative contaminants in nine Chinese medicinal herbs, as additives for health foods, was investigated in order to ensure food safety from this source. A highly sensitive isotope dilution-gas chromatography-tandem mass spectrometry (ID-GC-MS/MS) method combined with gel permeation chromatography (GPC) and solid-phase extraction (SPE) was developed. Calibration curves showed good linearity for all PAHs (R ^2?>?0.999), and the limit of quantification (LOQ) ranged from 0.42 to 2.7?µg?kg^?1. Average recoveries for these compounds were in the range of 52.5–117%, 52.6–119% and 81.4–108% at the concentrations of 10, 50 and 250?µg?kg^?1 with RSD of 1.8–15%, 0.9–15% and 1.0–15%, respectively. The proposed method was used for the analysis of nine Chinese medicinal herbs. Total levels of PAHs varied from 98.2?µg?kg^?1 (cassia seed) to 2245?µg?kg^?1 (eucommia bark). The highest level was found for phenanthrene (Phe) in liquorice root (631.3?µg?kg^?1), indigowoad leaf (551.0?µg?kg^?1), rose flower (435.2?µg?kg^?1) and eucommia bark (432.3?µg?kg^?1). The proposed method could provide a useful basis for safety monitoring of herbs and risk management for PAHs in the health food industry.     

Chemical composition, angiotensin-converting enzyme-inhibitory activity and antioxidant activities of few-flower wild rice (Zizania latifolia Turcz.)

BACKGROUND: The chemical compositions of the stem and leaf sheath of few‐flower wild rice were analysed. In addition, their extracts were evaluated for diphenylpicrylhydrazyl (DPPH) free radical‐scavenging activity, ferric‐reducing antioxidant power and angiotensin‐converting enzyme (ACE)‐inhibitory activity, since these are important properties of sources of nutraceuticals or functional foods. RESULTS: The stems contained more ascorbic acid (0.06 g kg^?1 fresh weight), protein (28.18 g kg^?1 dry weight (DW)), reducing sugars (308.54 g kg^?1 DW), water‐soluble pectin (20.63 g kg^?1 DW), Na₂CO₃‐soluble pectin (44.14 g kg^?1 DW), K (8 g kg^?1 dry matter (DM), S (6 g kg^?1 DM) and P (5 g kg^?1 DM) but less starch, total dietary fibre, Si, Na and Ca than the leaf sheaths. The DPPH free radical‐scavenging IC₅₀ values of the stem and leaf sheath extracts were 19.28 and 21.22 mg mL^?1 respectively. In addition, the ACE‐inhibitory IC₅₀ value of the stem extracts was 38.54 mg mL^?1. CONCLUSION: Both the stem and leaf sheath extracts exhibited good antioxidant properties, while good ACE‐inhibitory activity was detected only in the phosphate buffer solution extracts of the stem. Few‐flower wild rice could be processed into formula feeds for fish, poultry, etc. or functional foods for persons with high blood pressure. Copyright © 2011 Society of Chemical Industry     

Influence of degree of hydrolysis on functional properties and angiotensin I‐converting enzyme‐inhibitory activity of protein hydrolysates from cuttlefish (Sepia officinalis) by‐products

BACKGROUND: In Tunisia the cuttlefish‐processing industry generates large amounts of solid wastes. These wastes, which may represent 35% of the original material and constitute an important source of proteins, are discarded without any attempt at recovery. This paper describes some functional properties and the angiotensin I‐converting enzyme (ACE)‐inhibitory activity of protein hydrolysates prepared by hydrolysis of cuttlefish (Sepia officinalis) by‐products with crude enzyme extract from Bacillus licheniformis NH1. RESULTS: Cuttlefish by‐product protein hydrolysates (CPHs) with different degrees of hydrolysis (DH 5, 10 and 13.5%) were prepared. All CPHs contained 750–790 g kg^?1 proteins. Solubility, emulsifying capacity and water‐holding capacity increased while fat absorption and foaming capacity decreased with increasing DH. All hydrolysates showed greater fat absorption than the water‐soluble fraction from undigested cuttlefish by‐product proteins and casein. CPHs were also analysed for their ACE‐inhibitory activity. CPH3 (DH 13.5%) displayed the highest ACE inhibition (79%), with an IC₅₀ value of 1 mg mL^?1. CONCLUSION: Hydrolysis of cuttlefish by‐product proteins with alkaline proteases from B. licheniformis resulted in a product with excellent solubility over a wide pH range and high ACE‐inhibitory activity. This study suggests that CPHs could be utilised to develop functional foods for prevention of hypertension. Copyright © 2010 Society of Chemical Industry     

A new potassium tetrabromoaurate (III)-luminol chemiluminescence system for the determination of folic acid in milk powder

Abstract: A new chemiluminescence (CL) system based on the CL‐emitting reaction between potassium tetrabromoaurate (III) [Au(III)] and luminol in alkaline medium is described in this paper. On the basis of this study, folic acid (FA) could dramatically enhance CL intensities, and incorporated with flow injection (FI) and solid‐phase extraction (SPE), the novel CL system has been applied for the determination of FA in infant formula milk powder. Under optimum conditions, the CL intensities were linearly related to the concentration of FA in the range of 8.0 × 10^?8 to 4.0 × 10^?5 g/L with a correlation coefficient of 0.999, and the detection limit was 2.0 × 10^?8 g/L. The relative standard deviation was 3.5% for 1.0 × 10^?6g/L FA. The optimal conditions for the detection of FA were evaluated, and the interferences from some common inorganic ions and a couple of relevant organic compounds were also investigated. Practical Application: The new Au(III)–luminol chemiluminescent system is proposed for the determination of FA; it will be an adequate technique for the analysis of low FA concentrations in pharmaceutical preparations and food samples, and it will have potential analytical applications for other substances.     

Changes in chemical quality indices during long‐term storage of palm‐olein oil under heated storage and transport‐type conditions

Six quality indices, namely free fatty acids (FFA), peroxide value (PV), anisidine value (AV), oxidative stability index (OSI), total tocopherols and headspace volatiles (hexanal, t‐2‐hexenal and t,t‐2,4‐decadienal), were evaluated in a long‐term storage trial of 52 weeks at 50 °C of palm‐olein, a monounsaturated oil. Three concentrations of copper (0.035, 0.17 and 0.69 mg kg^?1) were added. FFA values for all the sample treatments increased slightly over the storage period but remained within acceptable limits. PV of the copper‐containing samples declined initially and then remained stable up to week 40, after which it increased slightly for the 0.035 and 0.17 mg kg^?1 samples. However, PV of the control (no added copper) increased steadily to above the acceptable limit. AV of the copper‐containing samples increased much more than that of the control. OSI and total tocopherol values of the copper‐containing samples were markedly lower than those of the control. t‐2‐Hexenal did not increase during the storage period, whereas hexanal increased in the copper‐containing samples but at a slower rate than in the control. Conversely, the copper‐containing samples had high levels of t,t‐2,4‐decadienal but the control had none. AV, OSI and total tocopherols are the most valuable quality indices for assessing monounsaturated oil quality, whereas FFA, PV and headspace volatiles can be misleading. Copyright © 2003 Society of Chemical Industry     

An improved method for the measurement of 3‐monochloropropanediol esters by matrix solid‐phase dispersion supported liquid–liquid extraction

3‐Monochloropropanediol (3‐MCPD) esters are contaminants produced from the high‐temperature processing of edible oils. The accurate measurement of 3‐MCPD using an easy‐to‐follow and reliable method that uses a readily available instrument is important. Here, we report an acid transesterification heptafluorobutyrylimidazole (HFBI) derivatisation method for the accurate measurement of 3‐MCPD esters in edible oils. We developed a dispersed matrix solid‐phase supported liquid–liquid extraction (DMSP‐SLE) system to remove impurities. Both the transesterification and DMSP‐SLE conditions were optimised. A good linear relationship was obtained within the range of 0.05–10 mg kg^?1 (R² ≥ 0.999) in both blank solvent and an oil sample. The limit of detection was 20.36 μg kg^?1. The average recovery of the 3‐MCPD esters spiked at 0.5, 1.0 and 2.0 mg kg^?1 into a blank oil matrix was in a range from 105.09 ± 2.77% to 120.16 ± 10.88%. The method we developed was further confirmed by performing detection on a Food Analysis Performance Assessment Scheme (FAPAS) sample.