Analysis of Furan and Its Derivatives in Food Matrices Using Solid Phase Extraction Coupled with Gas Chromatography-Tandem Mass Spectrometry.

The objective of this study was to develop a simultaneous analysis method of furan and its 10 derivatives in different food commodities. The results indicated that furan and its 10 derivatives could be separated within 9.5 min by using a HP-5MS column and gas chromatography-tandem mass spectrometry (GC-MS/MS) with multiple reaction monitoring mode for detection. Furthermore, this method could resolve several furan isomers, such as 2-methyl furan and 3-methyl furan, as well as 2,3-dimethyl furan and 2,5-dimethyl furan. The most optimal extraction conditions were: 5 g of the fruit or juice sample mixed with 5 mL of the saturated NaCl solution, separately, or 1 g of the canned oily fish sample mixed with 9 mL of the saturated NaCl solution, followed by the equilibration of each sample at 35 °C for 15 min, using a carboxen-polydimethylsiloxane SPME arrow to adsorb the analytes for 15 min at 35 °C for subsequent analysis by GC-MS/MS. For method validation of all the analytes in the different food matrices, the recovery was 76-117% and the limit of the quantitation was 0.003-0.675 ng/g, while the relative standard deviation (RSD%) of the intra-day variability range from 1-16%, and that of the inter-day variability was from 4-20%. The method validation data further demonstrated that a reliable method was established for the analysis of furan and its 10 derivatives in commercial foods.

Development of a GC-MS/MS method coupled with HS-SPME-Arrow for studying formation of furan and 10 derivatives in model systems and commercial foods.

Furan has been described as a carcinogen, being present in numerous food products available to the everyday consumer. The objectives of this study were to determine the formation of furan and its derivatives in 3 model systems during heating, with their contents being determined in selected commercial food products by HS-SPME Arrow coupled with GC/MS/MS. A high accuracy and precision was attained for the method developed in this study. The model system of 0.5 M glucose/alanine + 0.1 M ascorbic acid generated the highest furan level (5603.63 ng/g) when heated at 121 °C for 2 h. The addition of ascorbic acid favored formation of furfural and furfuryl alcohol, while linoleic acid favored formation of furfuryl alcohol. In addition, the total furan contents in various commercial foods ranged from 21.14 to 3183.39 ng/g. Most importantly, the outcome of model systems may be used to predict the presence of furan and its derivatives in commercial foods.

Improved Analytical Method for Determination of Furan and Its Derivatives in Commercial Foods by HS-SPME Arrow Combined with Gas Chromatography-Tandem Mass Spectrometry.

Owing to the presence of significant levels of toxic furan compounds reported globally in commercial foods by various food authorities, the objectives of this study were to develop an analytical method for determination of furan and its 10 derivatives in commercial foods using headspace-solid phase microextraction (HS-SPME)-Arrow coupled with gas chromatography-tandem mass spectrometry. Furan and its 10 derivatives were separated within 10 min by employing an HP-5MS capillary column with d4-furan as the internal standard for quantitation. The most optimal sample weight and extraction time for various commercial food samples, respectively, ranged from 1 to 5 g and 10-15 min depending on the sample variety. For extraction, carboxen/poly(dimethylsiloxane) (CAR/PDMS) cellulose was used with the temperature at 30 °C, equilibration time of 15 min, and desorption time of 3 min. The limit of detection ranged from 0.001 to 1.071 ng/g, while the limit of quantitation ranged from 0.003 to 3.571 ng/g. A high precision and accuracy were obtained for this method. The total furan content in commercial foods ranged from nd to 40 725.85 ng/g, in which the mean contents were the highest for brewed coffee (35 082.26 ng/g) and canned coffee (25 152.22 ng/g), while the lowest were for potato chip and cookies (0.57-1.48 ng/g), donut (1.50 ng/g), milk (0.34-30.38 ng/g), and oat (6.56 ng/g).

Effect of sterilization conditions on the formation of furan and its derivatives in canned foods with different substrates.

This study explored the effects of sterilization conditions on the formation of furan and its 10 derivatives in canned foods with a sterilizing value (F0) at 4. The contents of furans were determined by SPME arrow-GC-MS/MS, along with the furan precursors analyzed for elucidating the possible mechanism of furan formation. Results revealed that the total furan contents rose substantially in canned meat paste, tomato mackerel, chicken puree, tomato paste, pineapple slice, pineapple juice and carrot juice following sterilization. However, the total furan content did not change significantly ( p > 0.05) in canned oily mackerel, but decreased significantly ( p < 0.05) in canned apple puree after sterilization. With the exception of apple puree and pineapple slice, all the other canned foods showed a higher total furan content under low-temperature-long-time condition than that under high-temperature-short-time condition. Following heating, only the furan level showed a large increase in chicken puree, meat paste and tomato mackerel, whereas in canned fruit- and vegetable-based foods, the contents of furan and furfural showed a pronounced increase. The levels of alkylated furans were higher in sterilized samples containing high level of amino acid, while that of oxygenated furans were higher in sterilized samples containing high level of reducing sugar.

Evaluation of prenylflavonoids and hop bitter acids in surplus yeast.

This study developed a high performance liquid chromatography with diode array detection (HPLC-DAD) and tandem mass spectrometry (MS-MS) method for determination of prenylflavonoids and hop bitter acids in surplus yeast, a byproduct from beer brewing process. This method enabled the simultaneous separation of 4 prenylflavonoids and 20 hop bitter acids within 30 min by employing a Hypersil-Keystone HyPURITY C18 column and a gradient mobile phase composed of phosphoric acid aqueous solution at pH 1.6 and acetonitrile. For HPLC-DAD analysis, the limits of detection and limits of quantitation ranged from 0.04 to 0.15 µg/mL and from 0.12 to 0.45 µg/mL, respectively, and the recoveries ranged from 82.6 to 99.7%. The intra-day variability and inter-day variability ranged from 1.37 to 8.82% and from 0.68 to 9.74%, respectively. For qualitation by MS-MS, the positive mode was discovered to possess satisfactory collision capacity and high sensitivity for prenylflavonoids, while the negative mode was more suitable for the ionization of hop bitter acids. The content of hop bitter acids in surplus yeast were higher than that of prenylflavonoids, and isomers and oxidation products of hop bitter acids were found. This study has advantages in identifying more components, short separation time, satisfactory resolution, high accuracy and high precision.

Improved Analytical Method for Determination of Cholesterol-Oxidation Products in Meat and Animal Fat by QuEChERS Coupled with Gas Chromatography-Mass Spectrometry.

Cholesterol is widely present in animal fats and meat products and can undergo oxidation to form cholesterol-oxidation products (COPs) during heating. The objective of this study was to develop a QuEChERS method for the determination of COPs in edible animal fats and meat products via gas chromatography-mass spectrometry in which the required solvent volume and extraction time were reduced. By employing a DB-5MS capillary column (30 m × 0.25 mm i.d., 0.25 µm film thickness) and a temperature-programming method, seven COPs, cholesterol, and the internal standard 5α-cholestane could be separated within 19 min. The limits of detection and limits of quantitation based on the COP standards ranged from 0.16 to 180 ng/mL and from 0.32 to 400 ng/mL, respectively, and the recoveries ranged from 89.1 to 107.6% for boiled pork and from 80.5 to 105.6% for lard. The intraday variabilities for boiled pork and lard ranged from 2.27 to 6.87% and from 1.52 to 9.78%, respectively, whereas the interday variabilities ranged from 1.81 to 7.89% and from 3.57 to 9.26%, respectively. Among the various meat samples, fish showed the highest level of COPs (31.84 µg/g). For the edible fats, the COP contents in tallow (22.79-60.15 µg/g) were much higher than those in lard (0.152-2.55 µg/g) and butter (0.526-1.36 µg/g). Collectively, this method can be applied to determine COPs in cholesterol-containing foodstuffs.

Functional components in Scutellaria barbata D. Don with anti-inflammatory activity on RAW 264.7 cells.

The objectives of this study were to determine the variety and amount of various functional components in Scutellaria barbata D. Don as well as study their anti-inflammatory activity on RAW 264.7 cells. Both ethanol and ethyl acetate extracts were shown to contain the functional components including phenolics, flavonoids, chlorophylls, and carotenoids, with the former mainly composed of phenolics and flavonoids, and the latter of carotenoids and chlorophylls. Both extracts could significantly inhibit (p < 0.05) the production of lipopolysaccharide-induced nitric oxide, prostaglandin E2, interlukin-6, and interlukin-1ß, as well as the expressions of phosphor extracellular signal-regulated kinase and phosphor-c-Jun N-terminal kinase (p-JNK), but failed to retard tumor necrosis factor-α expression. Both ethanol and ethyl acetate extracts had a dose-dependent anti-inflammatory activity on RAW 264.7 cells. Furthermore, the anti-inflammatory efficiency can be varied for both ethanol and ethyl acetate extracts, which can be attributed to the presence of different varieties and amounts of functional components, as mentioned above. This finding suggested that S. Barbata extract may be used as an anti-inflammatory agent for possible future biomedical application.

Analysis of Heterocyclic Amines in Meat by the Quick, Easy, Cheap, Effective, Rugged, and Safe Method Coupled with LC-DAD-MS-MS.

The traditional way to analyze heterocyclic amines (HAs) is time-consuming and uses large amounts of solvents. The objective of this study is to develop a quick and simultaneous analysis method for multiple types of HAs contained in meat products. Results showed that 20 HAs and 1 internal standard (4,7,8-TriMeIQx) can be separated within 30 min using an Inspire C18 column and a gradient solvent system containing 10 mM ammonium acetate (pH 2.9) and acetonitrile. This process resulted in a high degree of separation. Using acetonitrile with 1% acetic acid as an extraction solvent, followed by primary and secondary amine, MgSO4, and C18EC as purified reagent, is highly suitable for extracting HAs using the quick, easy, cheap, effective, rugged, and safe method (QuEChERS). Tandem mass spectrometry with selected reaction monitoring mode were used for analysis, which indicated reasonable recovery (58.9-117.4%) for all 20 types of HAs along with limits of detection and quantification in the range of 0.003-0.05 and 0.01-0.05 ng/g, respectively.

Occurrence and exposure to polycyclic aromatic hydrocarbons in kindling-free-charcoal grilled meat products in Taiwan.

This study aimed to determine the contents of 16 PAHs in kindling-free-charcoal grilled meat and seafood products by GC-MS coupled with a QuEChERS method, and estimate the potential risk associated with consumption of those products in Taiwan. Results showed that the total PAHs contents ranged from 6.3±0.9 to 238.8±8.3 ng/g in poultry meat, 0.1±0.0-547.5±12.2 ng/g in red meat, and 6.6±1.4-249.7±6.4 ng/g in seafood products. Among various PAHs, the highly carcinogenic benzo[a]pyrene was detected in chicken breast grilled at 84°C (30 min), chicken heart at 100°C (26 min), chicken drumstick at 74°C (20 min), duck drumstick at 85°C (40 min), and lamb steak at 88°C (12 min), with its level amounting to 1.3±0.0, 2.4±0.1, 4.0±1.3, 3.1±0.0, and 5.8±0.5 ng/g, respectively. The generation of PAHs was associated with grilling time, temperature and fat content. Risk assessment of dietary exposure to PAHs revealed toxicity equivalent to range from ND - 6.174±0.505 µg/g and margin of exposure was >10,000, which agreed with the EFSA's definition of low public health concern. The lifelong average daily PAHs intake was higher for adults than for elderly people in Taiwan, however, consumption of kindling-free-charcoal grilled meat should not be a public health concern based on cancer risk potency.

Reduction of carcinogenic polycyclic aromatic hydrocarbons in meat by sugar-smoking and dietary exposure assessment in taiwan.

Polycyclic aromatic hydrocarbons (PAHs) represent an important pollutant in foods and/or the environment. This study aimed to determine the PAH contents in sugar-smoked meat by employing a quick, easy, cheap, effective, rugged, safe (QuEChERS) method combined with a GC-MS technique and assess the dietary exposure of PAHs in Taiwan. Results showed that the longer the sugar-smoking duration, the more the total PAH formation. By sugar-smoking for 6 min, the total PAH contents generated in red meat (33.9 ± 3.1-125.5 ± 9.2 ppb) were higher than in poultry meat (19.1 ± 2.0-28.2 ± 1.2 ppb) and seafood (9.1 ± 1.4-31.8 ± 1.8 ppb), with lamb steak containing the largest amount of total PAHs. Most importantly, the highly carcinogenic benzo[a]pyrene remained undetected in all of the sugar-smoked meat samples. In addition, the cancer risk due to dietary PAH exposure based on total intake of meat in Taiwan was <2 × 10(-7). This outcome demonstrates that sugar-smoking can be adopted to replace the traditional smoking process with wood as smoke source.

Evaluation of analysis of polycyclic aromatic hydrocarbons by the QuEChERS method and gas chromatography-mass spectrometry and their formation in poultry meat as affected by marinating and frying.

The objectives of this research were to develop a method for the determination of 16 polycyclic aromatic hydrocarbons (PAHs) in poultry meat by combining the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method with gas chromatography-mass spectrometry (GC-MS) and study their formation during marinating and frying. The recoveries of 16 PAHs ranged from 94.5 to 104% in blank samples and from 71.2 to 104% in poultry meat samples. The quantitation limits of 16 PAHs were from 0.02 to 1 ng/mL, with the intraday variability being from 2.4 to 6.6% [percent relative standard deviation (RSD%)] and interday variability being from 3.3 to 7.1% (RSD%). Most PAHs followed a time-dependent increase over a 24 h marinating period, with naphthalene being generated in the largest amount. Among the various poultry meat, chicken gizzard produced the highest level of total PAHs after 24 h of marinating. A similar tendency was observed for most PAHs during frying of poultry meat, but a high amount of total PAHs was shown in duck drumstick after 15 min of frying.

An improved high performance liquid chromatography-photodiode array detection-atmospheric pressure chemical ionization-mass spectrometry method for determination of chlorophylls and their derivatives in freeze-dried and hot-air-dried Rhinacanthus nasutus (L.) Kurz.

Rhinacanthus nasutus (L.) Kurz, a traditional Chinese herb possessing antioxidant and anti-cancer activities, has been reported to contain functional components like carotenoids and chlorophylls. However, the variety and amount of chlorophylls remain uncertain. The objectives of this study were to develop a high performance liquid chromatography-photodiode array detection-atmospheric pressure chemical ionization-mass spectrometry (HPLC-DAD-APCI-MS) method for determination of chlorophylls and their derivatives in hot-air-dried and freeze-dried R. nasutus. An Agilent Eclipse XDB-C18 column and a gradient mobile phase composed of methanol/N,N-dimethylformamide (97:3, v/v), acetonitrile and acetone were employed to separate internal standard zinc-phthalocyanine plus 12 cholorophylls and their derivatives within 21 min, including chlorophyll a, chlorophyll a', hydroxychlorophyll a, 15-OH-lactone chlorophyll a, chlorophyll b, chlorophyll b', hydroxychlorophyll b, pheophytin a, pheophytin a', hydroxypheophytin a, hydroxypheophytin a' and pheophytin b in hot-air-dried R. nasutus with flow rate at 1 mL/min and detection at 660 nm. But, in freeze-dried R. nasutus, only 4 chlorophylls and their derivatives, including chlorophyll a, chlorophyll a', chlorophyll b and pheophytin a were detected. Zinc-phthalocyanine was found to be an appropriate internal standard to quantify all the chlorophyll compounds. After quantification by HPLC-DAD, both chlorophyll a and pheophytin a were the most abundant in hot-air-dried R. nasutus, while in freeze-dried R. nasutus, chlorophyll a and chlorophyll b dominated.

Carotenoid composition in Rhinacanthus nasutus (L.) Kurz as determined by HPLC-MS and affected by freeze-drying and hot-air-drying.

Rhinacanthus nasutus (L.) Kurz (Trade name: Bai he ling zhi), a traditional medicinal herb, has been reported to possess anticancer and antioxidant activities. However, the composition of the major functional compounds, carotenoids, remains uncertain. The objectives of this study were to develop a high performance liquid chromatography-mass spectrometry (HPLC-MS) method for carotenoid composition determination in R. nasutus and for carotenoid change by freeze-drying and hot-air-drying. A total of 24 carotenoids were separated within 54 min by using a YMC C(30) column and a gradient mobile phase of methanol-acetonitrile-water (82 : 14 : 4, v/v/v) (A) and methylene chloride (100%) (B): 100% A initially, maintained for 10 min, decreased to 95% A in 25 min, 84% A in 30 min, 75% A in 37 min, 68% A in 40 min, 65% A in 47 min, and 55% A in 50 min with flow rate at 1 mL min(-1) and detection wavelength at 450 nm. The various carotenoids were identified by comparing the retention time, absorption spectra, Q-ratio and mass spectra of unknown peaks with reference standards as well as photoisomerized standards. Quantitation was carried out using an internal standard ß-apo-8'-carotenal, with all-trans-lutein and its cis isomers being present in the largest amount (862 µg g(-1)) in freeze-dried R. nasutus, followed by all-trans-violaxanthin (494 µg g(-1)), all-trans-ß-carotene and its cis isomers (479 µg g(-1)), all-trans-neoxanthin and its cis isomers (251 µg g(-1)), all-trans-α-carotene and its cis isomers (85.2 µg g(-1)), luteoxanthin (14.3 µg g(-1)), all-trans-zeaxanthin (3.94 µg g(-1)), ß-carotene-5,6-epoxide (3.45 µg g(-1)) and all-trans-ß-cryptoxanthin (1.03 µg g(-1)). Comparatively, some more carotenoids including cis-violaxanthin, luteoxanthin, cis-neoxanthin, neochrome, 13- or 13'-cis-lutein, 9- or 9'-cis-lutein, ß-carotene-5,6-epoxide, 9- or 9'-cis-ß-carotene, 13- or 13'-cis-ß-carotene, 15- or 15'-cis-ß-carotene and 13- or 13'-cis-α-carotene were generated in R. nasutus during hot-air-drying.

Antiproliferation effect and mechanism of prostate cancer cell lines as affected by isoflavones from soybean cake.

The objectives of this study were to determine the antiproliferation effect of prostate cancer cell lines LNCaP and PC-3 as affected by 4 isoflavone fractions prepared from soybean cake and isoflavone standards genistein and daidzein. With the MTT test, most treatments were effective in inhibiting prostate cancer cell growth at a low dose of 5 and 10 mug/mL. In cell cycle analysis, the fractions of aglycon, a mixture of acetylglucoside and aglycon, as well as genistein and a combination of genistein and daidzein standards exhibited a high G2/M ratio for LNCaP, as did the acetylglucoside, genistein and a combination of genistein and daidzein standards for PC-3. Results of Western blotting revealed an increase in p53 protein expression of LNCaP following treatments of the aglycon fraction, genistein and a combination of genistein and daidzein standards. However, all the treatments did not affect Bcl-2 protein expression significantly in both LNCaP and PC-3 cells. A decline in cyclin B1 expression of LNCaP was observed for all the treatments, with the mixture of acetylglucoside and aglycon possessing the most pronounced effect. But for PC-3, a decrease in cyclin B1 expression was shown for all the isoflavones, with the exception of malonylglucoside, glucoside and acetylglucoside fractions. The outcome of this study may provide a basis for possible production of functional food in the future with soybean cake as raw material.

Effects of different carriers on the production of isoflavone powder from soybean cake.

The objectives of this study were to use soybean cake as the raw material for the production of isoflavone powder and compare the effects of different carriers as well as drying methods on the powder quality. Results showed that with spray drying, a level of 40% maltodextrin as carrier produced the highest yield (mass) of isoflavone powder, followed by 10% gelatin and 1% sodium alginate. However, a reversed trend was observed for the isoflavone content. With 1% sodium alginate, freeze drying generated the greatest yield of isoflavone powder, followed by vacuum drying and spray drying. The isoflavone content also exhibited the same tendency. With poly-gamma-glutamic acid (gamma-PGA) as carrier, all six levels studied (0.57, 0.28, 0.14, 0.028, 0.014 and 0.003%) were capable of forming powder containing high amounts of total isoflavone, which was comparable to that using 1% sodium alginate by freeze drying. Both high- and low-molecular-weight gamma-PGA showed similar effects in terms of powder yield and isoflavone content.

Functional components in soybean cake and their effects on antioxidant activity.

The antioxidant activities of four fractions of isoflavones from soybean cake were evaluated and compared with those of ISO-1 and ISO-2 fractions, five isoflavone standards, and mixtures of two or four isoflavone standards, as well as four commercial antioxidants, using DPPH, TEAC, reducing power, metal ion chelating, conjugated diene, and TBARS assays. Both malonylglucoside and glucoside fractions were isolated using preparative chromatography with Diaion HP-20 as adsorbent, whereas acetylglucoside and aglycone fractions were separated with silica gel as adsorbent. The other two fractions, ISO-1 and ISO-2, were soybean cake extracts containing 12 isoflavones for the former and a combination of 4 fractions for the latter. Both acetylglucoside and ISO-1 fractions exhibited the highest efficiency in scavenging DPPH free radicals, whereas all six fractions were effective in inhibiting conjugated diene formation. However, a low reducing power was observed for all six fractions and isoflavone standards. The aglycone fraction and genistein standard showed a pronounced increase of TEAC value and a moderate decrease of TBARs value. For chelating metal ions, both ISO-1 and ISO-2 fractions were the most efficient. Overall, the isoflavone fractions showed a better antioxidant activity than the isoflavone standards, probably caused by the presence of some other functional components such as saponin, flavonoid, and phenolic compounds in soybean cake.