ABSTRACT
Benzoic acid (BA) is typically found in natural food; therefore, naturally occurring BA must be distinguished from added BA preservatives. In this study, we investigated BA levels in 100 samples of fruit products and their fresh fruits as raw materials using dialysis and steam distillation approaches. BA was detected in the range (minimum-maximum) of 2.1-1380 µg/g and 2.2-1950 µg/g in dialysis and steam distillation, respectively. Steam distillation indicated higher BA levels than dialysis.
Subject(s)
Benzoic Acid , Fruit , Benzoic Acid/analysis , Fruit/chemistry , Steam , Renal Dialysis , DistillationABSTRACT
The conventional analysis method has problems with extraction efficiency, operability, and reproducibility. In this study, we attempted to solve these problems and improve the analytical method to obtain sufficient extraction efficiency and good operability and accuracy. The conventional method was able to get sufficient extraction in dried meat products, where the extraction efficiency of the conventional method was low, by increasing the concentration of sodium hydroxide solution at the time of homogenization. Suction filtration after adding the defoaming agent was added allowed for accurate volume adjustment. The turbidity of the extract caused by insufficient addition of zinc acetate solution was removed by increasing the amount of zinc acetate solution that was added. Turbidity caused by starch was removed by adding pancreatin. The RSD of the quantitative values was improved by adding sodium hydroxide solution and 80-90â water and immediately homogenizing. Furthermore, by changing the dilution factor of the extract solution in the colorimetric method, the inhibition of coloration by reducing substances was suppressed, and more accurate quantitative values could be obtained than with the conventional method. The recovery rate was 78.5-105% (RSD 0.7-5.8%), which was a good result. This method was considered to be a useful analytical method that can contribute to improving the inspection accuracy of nitrite ion analysis.
Subject(s)
Nitrites , Zinc Acetate , Reproducibility of Results , Sodium Hydroxide , ColorimetryABSTRACT
In this study, we simultaneously determined three antioxidants, butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), and tert-butylhydroquinone (TBHQ), using HPLC equipped both with a photodiode array detector and a fluorescence detector in 25 minutes per sample. Due to the combined use of the two detectors, we could achieve improved target selectivity. Further, quantification at the specific wavelengths for each target substance particularly increased BHT detection sensitivity. This approach enabled us to avoid repeated measurements during daily inspections. Furthermore, detections were performed using LC-MS/MS instead of GC-MS to overcome the problem of helium gas shortage.In addition, we investigated antioxidant stability in standard solutions during storage. Although TBHQ was stable in methanol with ascorbic acid at -20â, ascorbic acid storage has possibility to lead to decrease in BHT and BHA concentrations. We recognized that the mixture of BHT and BHA dissolved in methanol at 4â and that of BHT, BHA and TBHQ dissolved in methanol with ascorbic acid at -20â were suitable for about one year.
Subject(s)
Antioxidants , Tandem Mass Spectrometry , Butylated Hydroxyanisole/analysis , Chromatography, High Pressure Liquid , Chromatography, LiquidABSTRACT
The Japanese official analysis method for determination of nitrate ions in food products used as food additives is associated with various challenges. In some kinds of cheese, the extract becomes suspended. The volume of extracted solution is often not accurate owing to the presence of residues in the solution. Moreover, the determination with liquid chromatography-ultraviolet detection (HPLC-UV) is difficult owing to the influence of impurities. Sake usually does not contain lipids or proteins ; therefore, its analysis can be simplified by omitting the co-precipitation steps to remove them. In the present study, for cheese, the amount of sodium hydroxide solution that causes suspension was reduced, and the influence of residues was removed by adjusting the volume after suction filtration. Whereas, sake was diluted with water and centrifuged. Furthermore, solid-phase extraction (SPE) method using cartridge containing carbon molecular sieve to remove the influence of impurities on the chromatogram was successfully established. The recoveries of the nitrate ions were good outcomes of 91.3-99.6% (CV 0.9-4.5%) (n=5). The analysis range was 0.010-0.20 g/kg for cheese, 0.010-0.20 g/L for milk, and 0.010-0.10 g/kg for sake. The developed analysis methods are considered useful, because various challenges of the official analysis method can be solved and the operation are efficient.
Subject(s)
Cheese , Food Analysis , Nitrates , Animals , Cheese/analysis , Chromatography, High Pressure Liquid , Food Analysis/methods , Nitrates/analysis , Reproducibility of Results , Solid Phase ExtractionABSTRACT
In this study, a new method was developed for simultaneously determining nine preservatives, that is, benzoic acid (BA), sorbic acid (SOA), dehydroacetic acid (DHA) and PHBAs (methyl p-hydroxybenzoate [PHBA-me], ethyl p-hydroxybenzoate [PHBA-et], isopropyl p-hydroxybenzoate [PHBA-ipro], propyl p-hydroxybenzoate [PHBA-npro]), isobutyl p-hydroxybenzoate [PHBA-ibut] and butyl p-hydroxybenzoate [PHBA-nbut]), in processed foods, employing liquid chromatography (LC). This procedure accelerated sample preparation and improved efficiency by employing modified quick, easy, cheap, effective, rugged and safe (QuEChERS) extraction without clean-up. Samples were prepared with 20 mL of acetonitrile/water (1:1) with the assistance of a ceramic stone. The extract solutions were diluted 10 times or according to the detection amount and then injected into an LC-PDA. This method showed good linearity, and the LOQs were 10 mg/kg for BA, SOA and DHA and 5 mg/kg for the PHBAs. When validating this method, the recoveries of the nine preservatives were in the range 77.0-99.6%, RSDr values were in the range 0.7-5.3% and those of RSDwr were in the range 2.3-8.4%. These results suggest that this new method is highly reproducible.
Subject(s)
Food Preservatives/analysis , Solid Phase Extraction , Chromatography, High Pressure LiquidABSTRACT
A new method for the simultaneous determination of two sweeteners (Advantame and Neotame) in processed foods using liquid chromatography (LC) with tandem mass spectrometry(MS/MS) was developed herein. Chromatographic separations were performed using an ACQUITY UPLC CSH C18 column at 40 °C via a mobile phase comprising 10-mmol/L ammonium formate and methanol. Samples were prepared via rapid dialysis using 30% methanol solution in a thermostatic shaker set at 160 rpm and 50 °C for 1 h. The matrix in the test solution had no effect on the identification and quantification of the compound without a clean-up step using solid-phase extraction (SPE). This method satisfied all validation criteria with a limit of quantification (LOQ) of 0.01 µg/g for all samples. Using this method, the amounts of Advantame and Neotame in 24 processed foods were subsequently investigated, with the results indicating their detection beyond the lower LOQ. Moreover, a multiple reaction monitoring information-dependent acquisition-enhanced product ion (MRM-IDA-EPI) method was developed and described to further enhance product-identification ability.
Subject(s)
Chromatography, Liquid , Dipeptides/analysis , Food Analysis/methods , Tandem Mass Spectrometry , Food Analysis/standards , Solid Phase Extraction , Sweetening Agents/analysisABSTRACT
A LC-MS/MS-based screening method was developed for stevia sweetener in processed foods. After extraction of stevia sweetener from processed foods by dialysis, the dialysate was diluted with water, and stevia sweetener was measured by LC-MS/MS. Recovery from 5 kinds of processed foods spiked with 10 mg/kg of stevioside ï¼SSï¼, 10 mg/kg of rebaudioside A ï¼RSï¼, or 100 mg/kg of α-glu-cosyltransferase-treated stevia ï¼Gtsï¼ product was excellent, and no interfering peak was observed. Thirty-six commercial processed foods indicated as containing "stevia" were analyzed using this established method. Among them, 33 contained SS, 33 contained RS, and 11 contained Gts. Five products contained both stevia extract and Gts.
Subject(s)
Diterpenes, Kaurane/analysis , Food Analysis/methods , Glucosides/analysis , Stevia/chemistry , Sweetening Agents/analysis , Chromatography, Liquid , Tandem Mass SpectrometryABSTRACT
A simple and useful method for the determination of nitrite in meat and fish products was developed. The sample (2.5 g) was extracted and cleaned up by dialysis in tris hydroxymethyl aminomethane solution with shaking at 80â for 2.5 hr. Nitrite in the dialysate was quantified by colorimetric analysis. Furthermore, the dialysate was cleaned up with SPE under cooling, and nitrite in the resulting solution was determined using LC-UV with an anion exchange column for confirmation. The recoveries of nitrite from frankfurter and fish sausage, fortified at the levels of 0.002 g/kg and the maximum usage dose (0.070 g/kg for meat products, 0.050 g/kg for fish sausage) ranged from 82.6 to 104.8% in colorimetric analysis and from 88.3 to 97.6% in LC-UV confirmation analysis. The values determined in various meat and fish products by the developed method and by the Japanese official method were approximately equivalent.
Subject(s)
Dialysis/methods , Fish Products/analysis , Food Additives/analysis , Food Analysis/methods , Meat/analysis , Nitrites/analysis , Chromatography, High Pressure Liquid/methods , Chromatography, Ion Exchange/methods , Chromatography, Liquid/methods , Colorimetry/methods , Spectrophotometry, Ultraviolet/methodsABSTRACT
The recoveries of xanthene dyes in the analysis of acidic tar-dyes in high-protein foods were improved by loading them onto polyamide columns at pH 8.5, instead of using the conventional pH 3-4 solution. The experimental scale was reduced to approximately half that of the conventional method. Furthermore, instead of eliminating the organic solvent in the extract by evaporation, the extract was diluted with water prior to PA column cleanup in order to reduce the ratio of organic solvent so that acidic tar-dyes would be better retained on the column. The above two procedures shortened the operation time and allowed for a simpler protocol. With this method, the recoveries of erythrosine, phloxine, and rose bengal from salted cod roe were 82, 88, and 74%, respectively. The recovery percentages were greatly improved compared to those achieved by conventional column loading at pH 3.5 (26, 44, and 18%, respectively). The recoveries of azo-dyes (Amaranth, New Coccine, Allura Red AC, Tartrazine, Sunset Yellow FCF) were also improved from 41-66 to 79-99%.
Subject(s)
Food Analysis/methods , Food Coloring Agents/analysis , Dietary Proteins , Hydrogen-Ion Concentration , Nylons , TartrazineABSTRACT
Following the previous report, a rapid dialysis method was developed for the extraction and purification of four artificial sweeteners, namely, sodium saccharide (Sa), acesulfame potassium (AK), aspartame (APM), and dulcin (Du), which are present in various foods. The method was evaluated by the addition of 0.02 g/kg of these sweeteners to a cookie sample, in the same manner as in the previous report. Revisions from the previous method were: reduction of the total dialysis volume from 200 to 100 mL, change of tube length from 55 to 50 cm, change of dialysate from 0.01 mol/L hydrochloric aqueous solution containing 10% sodium chloride to 30% methanol solution, and change of dialysis conditions from ambient temperature with occasional shaking to 50â with shaking at 160 rpm. As a result of these revisions, the recovery reached 99.3-103.8% with one hour dialysis. The obtained recovery yields were comparable to the recovery yields in the previous method with four hour dialysis.
Subject(s)
Aspartame/analysis , Aspartame/isolation & purification , Dialysis/methods , Food Analysis/methods , Phenylurea Compounds/analysis , Phenylurea Compounds/isolation & purification , Saccharin/analysis , Saccharin/isolation & purification , Sweetening Agents/analysis , Sweetening Agents/isolation & purification , Thiazines/analysis , Thiazines/isolation & purification , Calcium Carbonate , Chromatography, High Pressure Liquid , Citrates , Dialysis Solutions , Drug Combinations , Hot Temperature , Hydrochloric Acid , Magnesium Oxide , Methanol , Sodium Chloride , Time Factors , WaterABSTRACT
Extraction and clean-up methods were examined for the analysis of acidic tar dyes in various high-protein foods. 1% Aqueous ammonia followed by ethanol, 1% aqueous ammonia-ethanol (1 : 1) mixture, and 1% aqueous ammonia-tetrahydrofuran (1 : 1) mixture were used in sequence for boiled fish paste (kamaboko), pounded fish cake (hanpen), and sausage. The sausage extract was centrifuged at low temperature to solidify and remove the contained fat. Salted cod roe with red pepper was extracted twice with 1% aqueous ammonia-ethanol (1 : 1) mixture, followed by extraction with 1% aqueous ammonia-tetrahydrofuran (1 : 1) mixture. A divinylbenzene-N-vinylpyrrolidone copolymer column was used for the clean-up of xanthen dyes. In the case of clogging-prone samples, the same type of large-particle-size column was used. A polyamide column was used for clean-up of the other dyes. When each dye was added at 5 µg/g in the foods, recoveries from kamaboko, hanpen, and sausage ranged from 76 to 102%, and the average recovery from the two types of salted cold roe with red pepper ranged from 45 to 98%.
Subject(s)
Fish Products/analysis , Food Analysis/methods , Food Coloring Agents/analysis , Food Coloring Agents/isolation & purification , Tars/analysis , Tars/isolation & purification , Xanthenes/analysis , Xanthenes/isolation & purification , Hydrogen-Ion Concentration , Polyvinyls , Solid Phase Extraction/methodsABSTRACT
The effect of pH of the clean-up process in the analysis of 11 permitted tar dyes in high protein food was investigated by using a handmade polyamide column (PA column) and Oasis HLB. Boiled fish paste spiked with the 11 dyes was extracted with appropriate solvents and the pH of the extract was adjusted to 3.0-7.0 in increments of 0.5, followed by clean-up with the PA column. At pH 3.0-5.5, precipitate formed in the extract clogged the column, and the recoveries of R3, R104 and R105 were 26-68%. At pH 6.0-7.0, clogging was not observed and the recoveries of the 3 dyes were somewhat higher, at 38-79%. The recoveries of other dyes were more than 80% at pH 3.0-7.0. With Oasis HLB, column loading was conducted at pH 11.0, and the recoveries of the 3 dyes improved to 70-83%. In conclusion, all 11 dyes could be cleaned-up with the PA column and Oasis HLB and the recoveries exceeded 70%.
Subject(s)
Fish Products/analysis , Food Analysis/methods , Food Coloring Agents/analysis , Food Coloring Agents/isolation & purification , Meat Products/analysis , Tars/analysis , Tars/isolation & purification , Hydrogen-Ion Concentration , Nylons , Solid Phase Extraction/methods , SolutionsABSTRACT
A rapid dialysis method for the analysis of stevioside (SS) and rebaudioside A (RS) in foods was developed. Minced samples (10 g) were packed into 30 cm net length dialysis tubing with 30% methanol to increase the dialysis efficiency. The dialysis tubing was put in a 100 mL centrifuge tube, and the total fluid volume was made up to 100 mL with 30% methanol. Dialysis was done with shaking while heating at 50â. The dialysis times were reduced from 48-72 hr in the conventional method to 2 hr under these conditions. The dialysate was loaded on a C18 solid- phase extraction cartridge, and the cartridge was washed with 40% methanol. SS and RS were eluted from the cartridge with 80% methanol, and separated by reversed-phase HPLC. Recovery yields (%)of SS and RS, spiked at 0.02 g/kg in various foods, were 83.0-105.1% and the relative standard deviations were mostly less than 5%.
Subject(s)
Dialysis/methods , Diterpenes, Kaurane/analysis , Food Additives/analysis , Food Analysis/methods , Glucosides/analysis , Chromatography, High Pressure Liquid/methods , Diterpenes, Kaurane/isolation & purification , Food Additives/isolation & purification , Glucosides/isolation & purification , Solid Phase Extraction , Temperature , Time FactorsABSTRACT
A method for nicotinic acid (NA) and nicotinamide (NAA) analysis in meats was developed. NA and NAA were extracted from meats or meat products with metaphosphate aqueous solution. The extract was cleaned up with an Oasis MCX cartridge. The cartridge was washed with 2% acetic acid (v/v) and acetic acid-methanol solution. NA and NAA were eluted with ammonia-methanol solution. NA and NAA in the eluate were chromatographed on a Scherzo SM-C18 (3.0×150 mm, 3.0 µm) column with 20 mmol/L ammonium acetate containing 0.1% acetic acid-acetonitrile (97 : 3) as a mobile phase and were monitored at 261 nm. Quantification was performed by LC and LC-MS/MS. Calibration curves showed high linearity (correlation coefficient>0.998) between 1-25 µg/mL for LC and LC-MS/MS. Recoveries were 84-108% (CVâ¦5.8%) by HPLC and 79-105% (CVâ¦9.0%) by LC-MS/MS. The limit of quantitation for NA was 0.005-0.01 g/kg and that for NAA was 0.01-0.02 g/kg.
Subject(s)
Chromatography, High Pressure Liquid/methods , Chromatography, Liquid/methods , Food Additives/analysis , Food Analysis/methods , Food Contamination/analysis , Meat Products/analysis , Meat/analysis , Niacinamide/analysis , Nicotinic Acids/analysis , Solid Phase Extraction/methods , Tandem Mass Spectrometry/methodsABSTRACT
A simple and efficient method for the determination of propionic acid (PA) in foods was developed. The sample was cleaned up by dialysis, and PA in the resulting solution was extracted into ethyl acetate for GC analysis. Sodium sulfate was used as a salting-out agent in the extraction process, and GC-FID and GC-MS were successfully applied to the determination and confirmation of PA, respectively. The recoveries were in the range of 98.9-104.4% at the addition level of 0.2 g/kg from 6 foods, bread, cake, cheese, worcester sauce, vinegar-pickles and yogurt. To evaluate the performance of the developed method, recoveries from bread, cake and cheese were compared with those of the notified method at the maximal allowable addition level of PA as a preservative for each food. Recoveries of 98.2-99.5% for the developed method and 91.2-92.0% for the notified method were obtained. The analytical limit was 0.1 g/kg in samples for both determination and confirmation.