Gas Chromatography–Mass Spectrometry Analysis of 4-Methylimidazole in Balsamic Vinegars and Processed Sauces

A gas chromatography–mass spectrometry method was optimized for quantification of 4-methylimidazole [4-MEI] in balsamic vinegars and processed sauces. The method used ion-pair extraction with bis-2-ethylhexylphosphate and derivatization with isobutylchloroformate, followed by Gas Chromatography-Mass Spectrometry (GC–MS) quantification using 2-ethylimidazole as internal standard. Performance characteristics such as linearity, recovery, and repeatability were good in a broad range of concentrations, and the limit of detection was low enough (130 ug/kg) to detect the presence of small quantities of the compound. A total of 35 samples were analyzed, including balsamic vinegars and processed sauces containing caramel in the ingredients list (soy, Worcestershire, Tonkatsu, Marinara, and Oyster sauces). The presence of 4-MEI was consistent with the presence of ammonia caramel (E150 c and d) in the ingredients list, with average values of 2431 ug/kg for balsamic vinegars and 804 ug/kg for processed sauces. These 4-MEI amounts are almost tenfold higher than those described for caramels containing beverages, which support the necessity to take an effective control on these products.     

Determination of caramel colorants’ by-products in liquid foods by ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS)

2-Methylimidazole, 4-methylimidazole (2-MI and 4-MI), 2-acetyl-4-(1,2,3,4-tetrahydroxybutyl) imidazole (THI) and 5-hydroxymethylfurfural (5-HMF) are neo-formed compounds generated during the manufacture of caramel colours and are transferred to the processed food. These contaminants are known to have a toxicological profile that may pose health risks. Hence, to characterise THI, 2- and 4-MI and 5-HMF levels in liquid foods, an ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and sample preparation was divided into two analytical strategies depending on the concentration range expected in the type of foods targeted. For the determination of the imidazole substitutes (THI, 2- and 4-MI), a sample enrichment and clean-up step by strong cation solid-phase extraction was developed. This method is capable of quantifying over a range of 5 ng ml^–1 (LOQ) to 500 ng ml^–1 with recoveries of 75.4–112.4% and RSDs of 1.5–15%. For determination of 5-HMF, a standard addition method was applied covering the linear range of 0.25–30 µg ml^–1 with RSDs from 2.8% (for intraday precision) to 9.2% (for intermediate precision). The validated analytical methods were applied to 28 liquid food samples purchased from local markets. THI was found only in the beer samples at levels up to 141.2 ng ml^–1. For 2-MI, non-quantifiable traces were observed for all samples, while 4-MI was observed in all samples with large concentration variations (from < LOQ to 563.9 ng ml^–1). 5-HMF was found at expected concentrations, except for a sherry vinegar sample (113 µg ml^–1), which required a high level of dilution before following the standard addition protocol.     

Development of caramel colour with improved colour stability and reduced 4-methylimidazole

ABSTRACT

This study investigated the effect of chemical substances, such as Mg²⁺ (as magnesium sulphate), Zn²⁺ (as zinc sulphate), Fe²⁺ (as iron sulphate), ascorbic acid, and citric acid, on the formation of 4-methylimidazole (4-MI) and colour stability of caramel colour. The 4-MI concentration in the caramel colour without chemical substances was 963.10 μg/g, and this decreased the most (67.7%) with the addition of 0.1 molar ratio of citric acid. Colour stability was evaluated by measuring the total colour change (ΔE) after storage, and heating in pH 2, 4, and 7 solutions and 50% solution in ethyl alcohol. Among the chemical substances added to reduce 4-MI in the caramel colour, Mg²⁺ (0.1 molar ratio) and ascorbic acid improved the colour stability more than the others.     

Pressure-Thermal Kinetics of Furan Formation in Selected Fruit and Vegetable Juices

Furan, a potential carcinogenic compound, can be formed in array of processed foods. The objective of this study was to conduct kinetic studies in pineapple juice and assess the interactive effects of pressure (0.1 to 600 MPa) and temperature (30 to 120 °C) on furan formation. Additional experiments were carried out in tomato, watermelon, cantaloupe, kale, and carrot juice to understand the influence of matrix and juice pH. Furan was monitored in raw (control) and processed samples by automated headspace gas chromatography mass spectrometry, and quantified by calibration curve method with d₄-furan as internal standard. The data were modeled using zero-, first-, and second-order equations. The zero-order rate constants (k _T,P ), activation energy (E _a ), and Gibbs free energy of activation (ΔG ^?) of furan formation in thermally processed (TP; 90–120 °C) pineapple juice were found to be 0.036–0.55 μg/kg/min, 98–114 kJ/mol, and 173.9–180.5 kJ/mol, respectively. Furan concentration was negligible and close to the detection limit (0.37 μg/kg) after pressure treatment (600 MPa at 30 °C) of juice samples. For similar process temperatures, the rate constants of pressure-assisted thermally processed (PATP; 600 MPa at 105 °C) pineapple juice were lower than that of TP samples. Furan formation was influenced by juice matrix and pH. On the other hand, PATP markedly suppressed furan (0.7 to 1.6 μg/kg) in these selected juices. In conclusion, furan formation increased with process temperature and treatment time, while pressure treatment at ambient temperature did not promote its production. Furan formation in TP fruit juices was also influenced by juice matrix and pH, but these were not the significant factors for PATP-treated juices.     

The occurrence,exposure and risk assessment of perfluoroalkyl acids in food from mainland,China

ABSTRACT

To study the contamination of perfluoroalkyl acids (PFAAs) in Chinese food and the risk of dietary exposure for the Chinese population, the data of 17 PFAAs covering 38 cities throughout China in 15 groups of foods were collected for meta-analysis from published and available research literature. Using food consumption and body weight parameters, estimated dietary intakes (EDIs) were calculated for evaluation using the Scenario-Based Risk Assessment (SceBRA) modelling. Among food groups, the highest ΣPFAAs concentrations and EDI contributions were both found in poultry (363 ng/g), fish and shrimp (313 ng/g), dark vegetables (309 ng/g), fruits (116 ng/g) and pork (25 ng/g). The EDI of adults in the high-exposure scenario was about twice that of the intermediate-exposure scenario, while the EDI of children was about twice that of adults’ EDI in the intermediate-exposure scenario. In addition, the PFOS EDI for children under high exposure approached its tolerable daily intake (TDI). Therefore high dietary exposure to PFAAs is giving rise to an increased health risk, especially for children.     

Formation of carcinogenic 4(5)-methylimidazole in caramel model systems: A role of sulphite

Aqueous caramel model systems consisted the d-glucose/NH₃/sulphite were heated at 100 °C for 2 h and amounts of carcinogenic 4(5)-methylimidazole (4-MI) formed were determined. The amount formed ranged from 7.0 to 155.0 ppm. A system with 0.1 M sulphite yielded the greatest amount of 4-MI, which was 54% more than that yielded from a system without sulphite. When the amount of sulphite increased over 0.1 M, the amount of 4-MI reduced. The greatest reduction was achieved with 0.2 M sulphite by 68% compared to 0 M sulphite, suggesting that sulphite plays an important role in the formation of carcinogenic 4-MI in caramel colour. Also, a system with 0.1 M sulphite yielded the most intense caramel colour but the other levels of sulphite did not change the colour intensity significantly. Sulphite contributed slightly to the level of flavour chemicals evaluated using pyrazine formation. The results suggest that sulphite addition at appropriate amount reduces 4-MI formation in caramel colour without sacrificing flavour and colour formation.     

Determination of patulin in apple juice using magnetic solid-phase extraction coupled with high-performance liquid chromatography

ABSTRACT

An efficient magnetic sorbent consisting of benzofuran-2-carboxylic acid-loaded magnetic nanocomposite was successfully synthesised for pre-concentration of patulin from apple juice. The prepared magnetic nanocomposite was characterised by scanning electron microscopy, transmission electron microscopy and Fourier-transform infrared spectroscopy. Determination of enriched patulin was performed by high-performance liquid chromatography. The best adsorption conditions were 40 mg of sorbent, 50 ml of apple juice sample, pH 5, ambient temperature and 25 min; the elution conditions were 500 μl methanol, pH 5, ambient temperature, and 4 min. Under optimised conditions, pre-concentration factor was 100, linearity range was 1–400 μg l^–1 of patulin, limit of detection was 0.15 μg l^–1 and limit of quantification was 0.5 μg l^–1. When samples were determined 20 times, the recovery was 93.9–102.6% and the relative standard deviation was below 5.3%. In terms of proposed procedure, the developed method was successfully applied for patulin detection in apple juice samples.     

Evaluation of acrylamide and selected parameters in some Turkish coffee brands from the Turkish market

The purpose of this study was to measure acrylamide (AA) levels and selected parameters of different traditional Turkish coffees. AA, 5-hydroxymethylfurfural (HMF), total reducing sugar, protein, pH, moisture, dry matter (DM) as well as ash, caffeine and soluble solids content (SSC) in DM, L*, a*, b* colour parameters of coffee samples were determined and the correlation between AA level and these parameters were investigated. A total of 36 coffee samples (20 Turkish, 8 Dibek and 8 Terebinth coffee) from the Turkish market were examined. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was validated for the detection and quantitation of AA in coffee samples. The calibration curve was linear (R² ≥ 0.999) over the range of 30–1000 μg kg^?1. The limit of detection (LOD) and limit of quantification (LOQ) were found as 4.6 μg kg^?1 and 15.5 μg kg^?1, respectively. The amounts of AA in analysed coffee samples were in the range 31.1 ± 0.6 to 323.4 ± 5.4 µg kg^?1. The highest mean AA levels were found in Terebinth coffees (240.3 μg kg^?1) followed by Turkish coffees (204.3 µg kg^?1) and then Dibek coffees (78.6 µg kg^?1). No tested Turkish coffee samples had an AA concentration above the indicative value (450 µg kg^?1) for roast coffee recommended by the European Commission (EC) in 2011. In addition, a strong positive correlation was found between HMF values and AA amounts of selected coffee types.     

Dietary intake assessment of caramel colours and their processing by-products 4-methylimidazole and 2-acetyl-4-tetrahydroxy-butylimidazole for the Chinese population

ABSTRACT

The aim of the study was to assess the dietary intake of caramel colours and their by-products 4-methylimidazole (4-MEI) and 2-acetyl-4-tetrahydroxybutylimidazole (THI) for the Chinese population. Based on the typical and maximum reported use levels of caramel colours in 15 food categories, the dietary intakes of combined and single-class caramel colours of Classes I, III and IV were estimated with the food consumption data from the China National Nutrient and Health Survey. Using the mean values of 4-MEI and THI contents in Class III and Class IV Caramel colour samples, the exposures to 4-MEI and THI from dietary caramel colours were derived. The results showed that the combined and individual average dietary caramel colour intakes for the Chinese population of different age groups were estimated to be 232–60.3 mg kg^?1 bw day^?1 for combined caramels, 5.9–29.2 mg kg^?1 bw day^?1 for Class I, 7.7–29.6 mg kg^?1 bw day^?1 for Class III, 21.2–54.3 mg kg^?1 bw day^?1 for Class IV, which were far below the group acceptable daily intake (ADI) and respective ADIs. The combined intake of 4-MEI from Class III and IV caramel colours was estimated to be 3.8–5.2 μg kg^?1 bw day^?1 on average, and 12.9–27.1 μg kg^?1 bw day^?1 at 95th-97.5th percentile for the general population. The anticipated exposure to THI from Class III caramel colours was estimated to be 0.1–0.3 μg kg^?1 bw day^?1 on average and 0.5–1.7 μg kg^?1 bw day^?1 at 95th–97.5th percentile for the general population. The dietary caramel colours intakes and the exposures to 4-MEI and THI from dietary caramel colour for the Chinese population were considered to be of low health concern based on the present toxicological data. Soy sauce, vinegar and compound seasonings were found to be the main contributors to the dietary intake of caramel colours.     

Effects of Commercial-scale Pulsed Electric Field Processing on Flavor and Color of Tomato Juice

Effects of commercial‐scale pulsed electric field (PEF) processing on the flavor and color of tomato juice during storage at 4 deg;for 112 d were studied. Tomato juice was prepared by hot break at 88°C for 2 min and then thermally processed at 92° for 90 s or PEF processed at 40 kV/cm for 57 μs. The PEF‐processed tomato juice retained more flavor compounds of trans‐2‐hexenal, 2‐isobutylthiazole, cis‐3‐hexanol than thermally processed or unprocessed control tomato juice (P < 0.05). PEF‐processed juice had significantly lower nonenzymatic browning and higher redness than thermally processed or control juice (P < 0.05). Sensory evaluations indicated that the flavor of PEF‐processed juice was preferred to that of thermally processed juice (P < 0.01).     

Levels and temporal trend of bisphenol A in composite food samples from Canadian Total Diet Study 2008–2012

Food composite samples from the Canadian Total Diet Study which was conducted each year from 2008 to 2012 rotating between different cities were analysed for bisphenol A (BPA). The overall levels of BPA in the composite food samples from each of the five years from 2008 to 2012 were similar in general with averages (range) of 7.7 ng/g (0.20–106 ng/g), 7.8 ng/g (0.26–110 ng/g), 6.9 ng/g (0.20–84 ng/g), 7.7 ng/g (0.20–105 ng/g) and 9.0 ng/g (0.15–90 ng/g) for 2008, 2009, 2010, 2011 and 2012, respectively. Levels of BPA in most of the non-canned food composite samples were low and no particular trends were observed. In contrast, the trend of BPA levels in canned food composite samples over the five years (2008–2012) varies. BPA levels in most of the canned food composite samples from 2008 to 2012 were consistent in general (e.g. canned luncheon meat: 10–18 ng/g, canned baked beans: 18–25 ng/g). While BPA levels over the five years were found to decrease for some canned food composite samples (e.g., canned fish: 109 ng/g in 2009 vs. 51 ng/g in 2012), they were also found to increase for some other canned food composite samples (e.g. canned meat soups: 90–104 ng/g in 2011–2012 vs. 29 ng/g in 2008). Thus, recent changes in can coating for food packaging to BPA-free alternatives may have not been fully reflected in all canned food products over the period from 2008 to 2012. Continued monitoring is necessary to more fully assess the potential impact on dietary exposure by the use of BPA alternatives in food contact materials.     

3-Monochloro-1,2-propandiol (3-MCPD) in soy sauce from the Bulgarian market

The 3-monochloro-1,2-propandiol (3-MCPD) levels in soy sauces which contained hydrolysed vegetable protein were evaluated for the Bulgarian market. For analysis of 3-MCPD, a gas chromatography–mass spectrometry (GC-MS) method was applied with a linear range of 0.03–2.00 μg mL^?1 and a limit of detection (LOD) of 2.3 μg kg^?1 and a limit of quantification (LOQ) of 3.4 μg kg^?1. At these levels, the standard deviation was 5.1%, with recoveries between 81% and 102%. The method was applied to the analysis of 21 samples of soy sauce from the Bulgarian market. Results ranged from 3.7 to 185.6 μg kg^?1. Soy sauces produced from hydrolysed soy protein contained higher levels of 3-MCPD than naturally fermented sauces. In 38.4% of samples of Bulgarian origin, the 3-MCPD content was above the EU limit of 20 μg kg^?1. In all analysed samples, 33.3% had a 3-MCPD content above the EU limit.     

Relative exposure to beta-carbolines norharman and harman from foods and tobacco smoke.

Norharman and harman are two heterocyclic beta-carboline (9H-pyrido[3,4-b]indole) alkaloids with biological and potential toxicological activity that appear in foodstuffs and environmental sources. To assess the occurrence and distribution of these compounds and to estimate the exposure levels based on the detected amounts, numerous samples of foodstuffs and cigarette smoke were analysed by solid-phase extraction and high-performance liquid chromatography-fluorescence. The levels found of beta-carbolines were highly variable. Low processed foodstuffs (i.e. milk, yoghurt, uncooked meats and fish) did not contain norharman and harman above the detection limit. Others, however, contained relatively high concentrations (at the tens of ng g(-1) or microg l(-1) level) depending on the processing conditions as, for example, 'well-done' cooked meat and fish. The highest amounts of norharman and harman were found in brewed coffee (29-207 microg l(-1)), sauces (soy sauce and Tabasco, among others; 4-252 microg l(-1)), 'well done' cooked meat and fish (57-160 ng g(-1)), toasted bread (42-160 ng g(-1)), and fermented alcoholic beverages (n.d.-41 mug l(-1)). beta-Carbolines also occurred in a high amount in the mainstream of cigarette smoke (207-2780 ng/cigarette), which is an important contributor to daily exposure to these compounds. Based on these results, it is concluded that the daily exposure to beta-carbolines in humans might be from tens to hundreds of micrograms, with cigarette smoke, coffee, certain seasonings, cooked foods and alcoholic beverages, in this order, being the major contributors. Many other foodstuffs might also contribute with minor amounts of norharman and harman. Foods and tobacco smoke might be potential contributors to the reported endogenous presence of beta-carbolines in humans.     

An Improved HPLC-FLD for Fast and Simple Detection of Ethyl Carbamate in Soy Sauce and Prediction of Precursors

A high-performance liquid chromatography with fluorescence detection (HPLC-FLD) method for ethyl carbamate (EC) determination in Chinese soy sauce was developed and used to predict EC precursors, and extraction, derivatization, and chromatographic conditions were optimized systematically. Under optimal conditions, the limit of detection, linear range, and recoveries were 3.91 μg/L, 12.87–274.87 μg/L, and 81.5–95.4%, respectively. The method precision was less than 8.9% (RSD) and no significant difference was found between EC determinations measured by HPLC-FLD and GC/MS. Using the proposed HPLC-FLD method, the EC contents in Chinese soy sauces ranged from not detected to 64.88 μg/L (n = 19). Except for one soy sauce brand, the EC contents in low-salt solid-state fermented (LSF) soy sauces were lower than those in high-salt liquid fermented (HLF) soy sauces and were mainly affected by alcohol content. Moreover, the free ornithine and total arginine contents were significantly correlated with EC content in the soy sauce products. The results of this work provide a foundation for further study of EC formation and inhibition in Chinese soy sauces.     

Development of an Indirect Competitive ELISA for Analysis of Alternariol in Bread and Bran Samples

Alternariol (AOH) is one of the major mycotoxins produced by various species of Alternaria fungi. Natural occurrences of AOH have been reported in various foods, including fruits; processed fruit products such as apple juice, tomato products; wheat and other grains; oilseeds and products thereof, such as sunflower seeds, oilseed rape meal, and flax seed/linseed; and pecans. In this study, AOH-specific polyclonal antibodies were generated and developed an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) for monitoring AOH in bread and bran samples. The assay was very sensitive with a limit of detection (LOD) of 2.4?±?0.6 ng/g and a half maximal inhibitory concentration (IC₅₀) of 15.2?±?2.6 ng/g in bread and a LOD of 8.4?±?1.2 ng/g and IC₅₀ of 52.8?±?10.8 ng/g in bran extract. The assay was very specific to AOH and showed no cross-reactivity to alternariol monomethyl ether, altertoxin, altenuene, tentoxin, or tenuazonic acid. The effect of organic solvents on the assay was tested. The ELISA system tolerated methanol and acetonitrile as co-solvents at up to 5% content without significant loss of IC₅₀ value. Recoveries in all cases were greater than 75%, and the results using this method were comparable to those obtained from mass spectrometry methods. We conclude that this method is suitable for rapid detection of AOH in bread and bran samples, without expensive analytical equipment or time-consuming sample preparation.     

Dietary exposure to acrylamide in a group of Japanese adults based on 24-hour duplicate diet samples

Acrylamide is a probable human carcinogen and known human neurotoxin that can be generated in food through heating. Using a mathematical modelling approach, our previous study estimated long-term average dietary exposure to acrylamide in the Japanese people; however, the validity of these estimates remained unknown. Here, we aimed to obtain a more accurate estimate of acrylamide exposure that would reflect the usual practice of heat processing and consumption of foods in the population. We collected duplicate diet samples and dietary records during 24 h from a group of Japanese adults. A total of 110 duplicate diet samples were analysed for acrylamide by LC-MS/MS. Data from individual dietary records were used to examine the association between dietary acrylamide exposure and consumption of selected food groups (e.g., coffee, tea, confectioneries, and vegetables prepared at high temperature [deep-frying, stir-frying, sautéing, and baking]). Of the 110 homogenised diet samples, 108 contained detectable levels of acrylamide. Dietary exposure to acrylamide ranged from 8 to 1582 ng/kg body weight (bw)/day, with the mean value of 215 ng/kg-bw/day and median value of 143 ng/kg-bw/day. This mean value was higher than the value we previously estimated for Japanese adults using a mathematical approach. Multiple linear regression analysis showed log dietary acrylamide exposure was significantly associated with consumption of coffee and vegetables prepared at high temperature during 24-hr of sampling (adj. R² = 0.250, p < 0.001). We revealed significant difference in dietary acrylamide exposure between participants who had coffee and vegetables prepared at high temperature (median, 169 ng/kg-bw/day; range, 35–1224 ng/kg-bw/day, n = 42) and those who had none of them (median, 75 ng/kg-bw/day; range, 8–311 ng/kg-bw/day, n = 15) (Steel-Dwass test, p < 0.05).     

Evaluation of non-volatile taste components in commercial soy sauces

The dominating non-volatile taste compounds in commercial brewed soy sauces were determined by HPLC and evaluated on the contributions to overall taste. Aspartic acid and glutamic acid accounted for 8.77 to 147.98 mg/mL in ten commercial soy sauces samples. Lactic acid (ranging from 0.83 to 13.19 mg/mL) and pyroglutamic acid (ranging from 0 to 12.80 mg/mL) were the dominant organic acids, contributing to the acidity and ensuring a balance in taste of soy sauces. 5?-Inosine monophosphate was the most abundant nucleotide, followed by 5?-guanosine monophosphate, and they accounted for 0.30 to 3.54 mg/mL in ten soy sauces. According to the determination of non-volatile taste compounds in soy sauce samples, taste activity value (TAV) and equivalent umami concentration (EUC) of different soy sauces were calculated and compared. An exclusive cluster analysis based on TAV was proposed to classify the commercial soy sauces. The EUC value of new class A is much higher than other classes.     

Evaluation of Microbial Stability,Bioactive Compounds,Physicochemical Properties,and Consumer Acceptance of Pomegranate Juice Processed in a Commercial Scale Pulsed Electric Field System

This paper investigated the feasibility for pasteurizing raw (100 %) pomegranate juice in a commercial scale pulsed electric field (PEF) processing system. The juice was processed at 35 and 38 kV/cm for 281 μs at 55 °C with a flow rate of 100 L/h. Effect of PEF processing on microbial stability, color, °Brix, pH, sediment, antioxidant activity, total phenolic content, anthocyanin, and sensory properties after the treatments and during storage at 4 °C for 12 weeks were studied and compared to those of thermally processed juice. PEF treatments significantly (p?<?0.05) inhibited the growth of total aerobic bacteria, which remained at <2.5 log colony-forming units (CFU)/ml during the 12-week storage. No yeast and mold were detected (<0.69 log CFU/ml) in the PEF-treated juices during storage up to weeks 10 and 12, which is similar to the thermally processed juice. There were no significant differences in pH and °Brix values between the PEF processed juice and unprocessed juice. PEF processing did not alter the contents of total phenolics and anthocyanin as compared to unprocessed juice. PEF processing had significantly (p?<?0.05) less impact on the color of pomegranate juice than thermal processing. PEF-treated juice had the same consumer satisfaction scores as the unprocessed juice, which were significantly (p?<?0.05) higher than thermally processed juice samples. There was no significant difference between the two PEF treatments in all results. This study demonstrated that PEF technology extended microbial shelf-life and preserved the major quality and nutritional characteristics of pomegranate juice, and hence, is technically feasible for commercialization in the juice industry.     

The potential of NIR spectroscopy for the detection of the adulteration of orange juice

Near-infrared spectroscopy was used to investigate the adulteration of 65 authentic concentrated orange juice samples obtained from Brazil and Israel. These samples were adulterated with 100 g kg^?1 additions (ie 100 g added to 900 g) of (1) orange pulpwash, (2) grapefruit juice, and (3) a synthetic sugar/acid mixture and with 50 g kg^?1 additions (ie 50 g added to 950 g) of (4) orange pulpwash, and (5) grapefruit juice. All samples were scanned on the NIR systems 6500 spectrophotometer over the 1100-2498 nm wavelength range. Principal component analysis was used to reduce each spectrum to 20 principal components. Factorial discriminant analysis was used to distinguish between the different sample groups. Using orange juice and orange juice adulterated at the 100 g kg^?1 level, accurate classification rates of 94–95% were obtained. To classify samples adulterated at the 50 g kg^?1 level, the calibration development sample set had to be augmented by the inclusion of samples adulterated at this lower level—after this augmentation, an accurate classification rate of 94% was obtained. The results demonstrated that the application of principal component and factorial discriminate analysis to NIR reflectance spectra can detect the adulteration of orange juice with an average accuracy of 90%. Furthermore, not one adulterated sample was predicted as being an authentic orange juice throughout the entire test regime.     

A Simple and Rapid Method for Determination of Patulin in Juice by High Performance Liquid Chromatography Tandem Mass Spectrometry

A simple and rapid method was developed for analysis of patulin in juice using ultra performance liquid chromatography coupled with tandem mass spectrometry. The samples were purified by an Oasis MAX 96-Well Plate. Chromatographic separation was performed on an ACQUITY UPLC® HSS T3 column with gradient elution using acetonitrile and water as mobile phase. Analytes was quantified by external calibration curves over the ranges of 0.50–50 μg/L, with correlation coefficients > 0.9986. The LOD and LOQ in juice sample were 0.30 and 1.0 μg/L, respectively. Recoveries of the method (spiked at levels of 1, 5, 25 and 50 μg/L) ranged from 91.6% to 95.7%, while intraday and interday relative standard deviations were 6.87–11.0% and 6.53–11.6%, respectively.