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1.
The two novel preconcentration and separation methods based on adsorption onto Amberlite XAD‐1180 and Amberlite XAD‐16 polymeric resins for spectrophotometric determination of sunset yellow dye were developed. The parameters, affecting the quantitative recovery, including pH, sample and eluent flow rates, eluent type, sample volume, were investigated and optimised. The interference effects of some cations, anions and widely used dye were also studied. At the optimum conditions, detection limits of the methods were found as 2.0 and 1.6 μg L?1 for Amberlite XAD‐1180 and Amberlite XAD‐16 resins, respectively. Linear dynamic ranges of the methods were obtained in the range of 0.2–50.0 and 0.2–20.0 μg mL?1 for Amberlite XAD‐1180 and Amberlite XAD‐16 resins, respectively. The relative standard deviations were below than 7% and 5% for Amberlite XAD‐1180 and Amberlite XAD‐16 resins, respectively. The determination of dye was performed at 483.0 nm using spectrophotometry. Validations of the methods were performed comparatively with determination of the sunset yellow content of some foodstuffs and pharmaceuticals.  相似文献   

2.
This study presents a solid phase extraction (SPE) procedure for preconcentration and separation of Cu(II), Cd(II), Pb(II) and Ni(II), as their diethyldithiocarbamate chelates on Sepabeads SP‐207 resin using flame atomic absorption spectrometry. The parameters, including pH, sample volume, eluent type and volume etc., were optimised. The influences of the some alkali, alkali earth and transition metal ions on the involvement of copper(II), cadmium(II), lead(II) and nickel(II) were also examined. The preconcentration factor was calculated as 50. The limit of detections of the analyte ions (k = 3, N = 21) were 0.18 μg L?1 (Cu), 0.17 μg L?1 (Cd), 0.55 μg L?1 (Pb) and 1.67 μg L?1 (Ni). GBW 07605 Tea and NRCC‐DORM‐2 Dogfish Muscle certificated reference materials were used for confirm of method. The method was successfully performed for determination of Cu(II), Cd(II), Pb(II) and Ni(II) ions in water and food samples. The relative standard deviation was found to be lower than 7%.  相似文献   

3.
Physicochemical characterisation and oxidative stability of refined hoki oil, unrefined hoki oil and unrefined tuna oil were carried out in the present study. Tuna oil contains a higher percentage of polyunsaturated fatty acids (42.57%) than the hoki oils (28.79–30.13%), which have higher percentages of monounsaturated fatty acids (45.02–47.16%). All oils showed a good ratio of n‐3 to n‐6 fatty acid (7.01–8.10). Cholesterol contents in the unrefined hoki (5149.40 μg g?1) and tuna (2045.48 μg g?1) oils were higher than the refined hoki oil (1411.27 μg g?1). Tuna has a higher concentration of natural α‐tocopherol (752.49 μg g?1) but lower concentration of vitamin A (110.99 μg g?1) than unrefined hoki oil (151.44 μg g?1 and 997.60 μg g?1, respectively). Higher percentages of unsaponifiable matter were found in the hoki oils (4.90–7.24%) compared with the tuna oil (0.56%). The hoki oils appear more yellow than the tuna oil, which is darker by comparison. Moisture, p‐anisidine value and free fatty acid contents in the hoki oils were lower than the tuna oil. Other indicators of oxidative stability showed that the hoki oils were more stable than the tuna oil.  相似文献   

4.
The objective of this study was to determine the influence of 4‐ethylcatechol (4‐EC) on the sensory profile of Brettanomyces‐contaminated Merlot wine and evaluate electronic tongue discrimination. Using sensory evaluation panels, the consumer detection threshold (DT) and the consumer rejection threshold (CRT) of 4‐EC were determined in Merlot containing 493, 714, 1035 and 1500 μg L?1 4‐EC. The DT of 4‐EC in Merlot was 823 μg L?1, while the CRT was 1323 μg L?1. The electronic tongue discriminated index (DI = 82%) among the samples, with hierarchical clustering showing a clear distinction between the control sample and the spiked samples. The lowest concentration distinguished by the electronic tongue was 493 μg L?1, a lower value than the sensory threshold determined. These findings suggest that for the detection of 4‐EC in Merlot, the e‐tongue may be more sensitive than some consumers and the e‐tongue may be a suitable methodology for detection of subthreshold concentrations of chemical compounds in wine.  相似文献   

5.
This study examined the ability of five Amberlite resins coupled with ultrasound‐assisted water extraction for the recovery and enrichment of bioactive procyanidins and total phenolics from cranberry pomace. Static adsorption showed that XAD‐7HP had the highest adsorption capacity for procyanidins (52.2 mg/g resin) and total phenolics (99.1 mg/g resin) whereas XAD‐761 had the lowest. Adsorption of procyanidins fitted better to pseudo‐second‐order kinetics than pseudo‐first‐order kinetics. Isotherm adsorption on XAD‐7HP suggested that Langmuir isotherm was a better model to describe the adsorption of procyanidins while Kemkin–Pyzhev equation was better for total phenolics based on higher coefficient of determinations (R2). Dynamic tests on XAD‐7HP suggested that the flow rate of 7 and 8 mL/min were the optimum conditions for adsorption and desorption of procyanidins, respectively. Measurements using HPLC revealed that adsorption increased the contents of procyanidins and total phenolics by 4.57‐ and 4.73‐folds, respectively, compared to the initial extracts. This research showed that Amberlite XAD‐7HP resin adsorption coupled with ultrasound‐assisted water extraction is an efficient method to separate and concentrate procyanidins from cranberry pomace.  相似文献   

6.
We investigated the explosive process effect on antioxidant activities of coffee bean. The total polyphenol contents of powdered extract of explosive puffing coffee bean at 0.75 MPa (PEP 7.5) and powdered extract of explosive puffing coffee bean at 0.9 MPa (PEP 9.0) were at a significantly higher than that of the powdered extract of roasting coffee bean (PER) (< 0.05). PEP 7.5 showed the highest levels of 3‐CQA (86.23 μg mg?1), 4‐CQA (43.71 μg mg?1), and 5‐CQA (31.66 μg mg?1), and PEP 9.0 had also similar levels of chlorogenic acids, with 3‐CQA (77.99 μg mg?1), 4‐CQA (43.71 μg mg?1), and 5‐CQA (30.32 μg mg?1). PEP 7.5 and PEP 9.0 showed relatively higher antioxidant capacities in DPPH, ABTS, taurine, FRAP, and β‐carotene/linoleic acid assays. PEPs partly recovered the HepG2 cell damage induced by t‐BOOH. These results suggest that puffed coffee has beneficial health effects, and could be used for the development of novel processed coffee products.  相似文献   

7.
The processing of peaches to produce fruit pulp generates solid and liquid wastes rich in phytochemicals, such as carotenoids; thus, the objective of this work was to study the use of this waste for carotenoid extraction based on a complete experimental design and using response surface methodology. The parameters studied were the amount of solvent (20–50 mL), the number of extractions (1–5) and the extraction time (10–30 min). The extracts were analysed by spectrophotometry and the optimised conditions by HPLC. The optimised results were four extractions of 10 min using 38.5 mL of ethanol, which presented a yield of 168.59 μg g?1 DW of total carotenoids of which 67.55 μg g?1 corresponds to β‐carotene, 86.75 μg g?1 to cryptoxanthin, 12.08 μg g?1 to zeaxanthin and 2.2 μg g?1 to lutein, which representing 66% of extraction pigments relative to the total content of carotenoids present in the peach waste.  相似文献   

8.
This study aimed to establish an analytical method for α‐dicarbonyl compounds (α‐DCs) including glyoxal, methylglyoxal and diacetyl, to determine the content of α‐DCs in 101 various alcoholic beverages using gas chromatography–nitrogen phosphorous detector (GC‐NPD) and to perform exposure assessment. The limit of detection and limit of quantification for α‐DCs were 0.05–0.22 and 0.15–0.70 μg g?1, respectively. The accuracy and precision were validated in five matrices. The raspberry fruit wine had the highest value at 139.74 μg g?1 total α‐DCs. The lowest α‐DC concentration among the beverages was detected in rice wine (Makgeolli) at 1.59 μg g?1. The levels of α‐DCs in various samples were detected as follows: 1.59–56.68 μg g?1 in rice wine (Makgeolli), 2.73–16.77 μg g?1 in beer, 8.22–139.74 μg g?1 in fruit wine and 8.17–91.56 μg g?1 in rice wine (Cheongju). The estimated daily intake of α‐DCs in the intake‐only group and population group was calculated as 4.22–97.94 μg kg?1 bw day?1 and 0.28–7.13 μg kg?1 bw day?1, respectively.  相似文献   

9.
In this study, we prepared candied paprika from various coloured fresh paprika and compared the changes in phytochemicals and quality for 42 days by analysing carotenoids, ascorbic acids and total phenolic content, and by assessing sensory and instrumental qualities. We identified five types of carotenoids from candied red paprika (CRP) and three from candied orange paprika (COP) and candied yellow paprika (CYP). At 0‐day storage, capsanthin and β‐carotene in CRP were quantitatively analysed to 26.96 μg g?1 fw and 3.81 μg g?1 fw, zeaxanthin and β‐carotene in COP were 9.35 μg g?1 fw and 4.16 μg g?1 fw, and lutein and β‐carotene in CYP were 0.27 μg 100 g?1 fw and 0.70 μg 100 g?1 fw, respectively. After 42‐days storage, CRP retained approximately 68.6% carotenoids, COP retained 40%, and CYP retained 33%. Ascorbic acid and total phenolic content decreased during storage as carotenoids did. However, rates of decrease were different in different coloured paprika, especially, ascorbic acid in COP and phenolic acid in CRP were considerably conserved for 42 days. Hardness, springiness and chewiness in all samples were significantly increased by 14‐days storage and maintained until 42‐days storage, and all the sensory parameters, including colour, appearance, odour, texture, paprika flavour and overall consumer preference showed no differences until 28 days.  相似文献   

10.
Caxiri is a fermented alcoholic beverage made from cassava, corn and sweet potatoes by indigenous people in Brazil. Saccharomyces cerevisiae Rhodotorula mucilaginosa, Lactobacillus fermentum, Bacillus subtilis and L. helveticus were the main microbial species detected. Maltose was the main carbohydrate found (19.12 g L?1), and lactic acid (15.09 g L?1) and ethanol (92.16 g L?1) were also found in high concentrations. Gas chromatography‐flame ionisation detector was used to identify thirteen volatile compounds. Among these volatiles, the higher concentrations were decanoic acid (123.04 μg L?1) for the acids, diethyl malate (88.32 μg L?1) for the esters, furfural (109.31 μg L?1) for the aldehydes, 2‐phenylethanol (1022.76 μg L?1) for the alcohols and 1,1‐diethoxyethane (226.24 μg L?1) for the others. This study contributes to increasing knowledge of the microbiota present in the alcoholic fermentation produced from cassava, corn and sweet potatoes.  相似文献   

11.
R‐phycoerythrin (R‐PE) was purified from the red algae Bangia fusco‐purpurea after 35–50% ammonium sulphate fractionation followed by ion‐exchange column chromatography on DEAE‐Sepharose, resulting in a purity (A565/A280) ratio of 5.1. The circular dichroism spectroscopy results suggested that the structure of R‐PE is predominately helical. The antioxidant activity of R‐PE was studied and revealed changes in conformation and antioxidant activity at different temperatures and pH values. After in vitro‐simulated gastrointestinal (GI) digestion of R‐PE, the scavenging activity of ABTS radical (EC50, 769.9 μg mL?1), DPPH radical (EC50, 421.9 μg mL?1), hydroxyl radical (EC50, 32.4 μg mL?1) and reducing power (A700 = 0.5, 625.8 μg mL?1) were measured. Gel filtration chromatography analysis showed that the molecular weight distribution of the final GI digest that still contained high antioxidant activity was <3 kDa. Our present results indicate that digestion‐resistant antioxidant peptides of R‐PE may be obtained by in vitro GI proteinases degradation.  相似文献   

12.
An effective, simple and rapid analytical method using HPLC was developed for the analysis of monosodium glutamate (MSG) in various food samples obtained from local market in Turkey. The determination of MSG was performed by its derivatisation with o-phthaldialdehyde (OPA). A high-performance liquid chromatography-ultraviolet/diode array detection method was performed by using C18 (150 mm × 4.6 mm, 2.7 μm) column with the mobile phase consisting of 10 mm phosphate buffer solution (pH = 5.90) and methanol (75:25, v/v). The applied method was optimised and the validated. The method was linear from 1 to 50 μg mL−1 of MSG. The correlation coefficient value of the developed method was obtained as R2 = 0.9999. The limit of detection and limit of quantification limits were 0.015 and 0.050 μg mL−1, respectively. MSG contents of the food samples range from 0.09 g kg−1 to 120.80 g kg−1. The validated method was successfully applied for the analysis of MSG in several food samples.  相似文献   

13.
A total of twenty‐eight mycotoxins were surveyed in wine (red, white and rose), cider (white and rose) and their cork stoppers from eight countries. Toxins of different fungi genera were detected as follows: Alternaria (ATs: alternariol – AOH; alternariol methyl – AME) and Penicillium/Aspergillus (ochratoxin A – OTA; penicillic acid – PAC). Toxins and levels varied with the sample types and country of origin. Wine presented contamination of OTA, AOH and AME. OTA was detected in forty‐one wine samples with levels ranging from 0.01 to 0.86 μg L?1, below EU legislation. AOH and AME were detected in thirty‐three and eight of wines samples, respectively, at levels from 0.2 to 13.3 μg L?1, while no contamination was detected in ciders up to the method LOQs. Regarding the cork stoppers toxins detected, they were AOH, AME and PAC. Corks of red wine from different countries had levels of OAH and AME ranging from 5.0 to 101.0 and 2.5 to 5 μg g?1, respectively. It is necessary to pay more attention on the corks processing and cork type used in the bottles as, different from the ordinary ones, the ground bark and compressed type did not have toxins detected.  相似文献   

14.
We evaluated the effects of two additive mixtures (sodium ascorbate 1 g kg?1, sodium citrate 1 g kg?1 and sodium acetate 1.75 or 2.5 g kg?1) on the microbiological and physical–chemical characteristics of non‐prepacked beef burgers stored in air at 4 °C or 12 °C for 96 h. Total microbial count reached 7 Log CFU g?1 48 h later in treated samples at 4 °C. The mixture containing the higher acetate concentration led to a smaller increase in Gram‐negatives, in particular Pseudomonas (2 Log of difference towards control samples at 96 h); at 12 °C, a 1.7 Log difference in Enterobacteriaceae was also shown. Total viable basic nitrogen was significantly lower in the treated samples at 12 °C. The addition resulted in pH stabilisation and lower cooking loss and positively influenced the a* index of burgers at 4 °C. Clearly, the use of these mixtures should not be a substitute of good hygienic practices and optimal storage conditions.  相似文献   

15.
The in vitro inhibitory activities of different seed extracts prepared from cranberry bean mutant SA‐05 and its wild‐type variety Hwachia against aldose reductase, α‐glucosidase and α‐amylase were examined. The results indicated that the polyphenolics‐rich extracts obtained using 800 g kg?1 methanol and 500 g kg?1 ethanol demonstrated inhibitory activities against aldose reductase (IC50 of 0.36–0.46 mg mL?1) and α‐glucosidase (IC50 of 1.32–1.94 mg mL?1). The 500 g kg?1 ethanol extracts also showed α‐amylase inhibitory activities (IC50 of 70.11–80.22 μg mL?1). Subsequent extracts, prepared further with NaCl and H2O from precipitates of 800 g kg?1 methanol or 500 g kg?1 ethanol extracts, exhibited potent α‐amylase inhibitory activities (IC50 of 17.68–38.68 μg mL?1). A combination of 500 g kg?1 ethanol extraction plus a subsequent H2O extraction produced highest polyphenolics and α‐amylase inhibitors. The SA‐05 α‐amylase inhibitor extracts showed greater inhibitory activities than that of Hwachia. Thus, cranberry bean mutant SA‐05 is an advantageous choice for producing anti‐hyperglycaemic compounds.  相似文献   

16.
A separation–enrichment technique for the determination of trace amounts of copper(II), cobalt(II), lead(II), and iron(III) as violuric acid chelates on multiwalled carbon nanotubes at pH 6.0 was established. Analytes were determined by flame atomic absorption spectrometry. The effects of some analytical parameters like pH, amounts of violuric acid, flow rates, eluent type, and sample volume were investigated. The influences of the matrix ions were also investigated. The relative standard deviations for analyte elements were below 10%. The quantification limits of the analyte ions were found as 0.36 μg g−1 for copper, 0.43 μg g−1 for lead, 0.15 μg g−1 for cobalt, and 0.38 μg g−1 for iron. The accuracy of presented method was checked by the analysis of TMDA 54.4 fortified lake water, NIST SRM 1515 apple leave, and HR-1 Humber river sediment certified reference materials. The method was applied to analyte contents of table salt samples from different origin. The levels of iron in the analyzed table salt samples were found in the range of 1.6–6.4 μg g−1, while lead was found in only one sample as 5.0 μg g−1. In all other samples, cobalt, lead, and copper were found below the quantification limits of the analytes.  相似文献   

17.
This study presents the effect of heat treatment of chickpea seeds on biological activity of peptides obtained by in vitro gastrointestinal digestion. The most significant antiradical activity against ABTS+? expressed as IC50 value was observed for 3.5‐ to 7‐kDa peptide fraction from TC hydrolysate (41.01 μg mL?1). In turn, peptide fraction of 3.5–7.0 kDa obtained from raw chickpea seeds hydrolysate showed the highest antiradical activity against DPPH? and Fe2+ chelating activity with IC50 value of 20.94 and 52.53 μg mL?1, respectively. The highest Cu2+ chelating activity was observed for peptides obtained from TC hydrolysate (IC50 = 56.60 μg mL?1). Peptide fraction <3.5 kDa from TC hydrolysate demonstrated the most significant reducing power (0.362 A700/μg mL?1). The peptide fraction of 3.5–7 kDa from TC hydrolysate also showed the highest fibroblast growth‐stimulating activity. These results indicated that the heat treatment process has no significant effect on antiradical activity against DPPH? and Fe2+ chelating ability of peptides.  相似文献   

18.
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.  相似文献   

19.
Three phytosterols were isolated from Musa spp. flowers for evaluating their capabilities in inhibiting glucosidase and amylase activities and glycation of protein and sugar. The three phytosterols were identified as β‐sitosterol (PS1), 31‐norcyclolaudenone (PS2) and (24R)‐4α, 14α, 4‐trimethyl‐5α‐cholesta‐8, 25(27)‐dien‐3β‐ol (PS3). IC50 values (the concentration of inhibiting 50% of enzyme activity) of PS1, PS2 and PS3 against α‐glucosidase were 283.67, 11.33 and 43.10 μg mL?1, respectively. For inhibition of α‐amylase, the IC50 values of PS1, PS2 and PS3 were 52.55, 76.25 and 532.02 μg mL?1, respectively. PS1 was an uncompetitive inhibitor against α‐amylase with Km at 5.51 μg mL?1, while PS2 and PS3 exhibited a mixed‐type inhibition with Km at 52.36 and 2.49 μg mL?1, respectively. PS1 and PS2 also significantly inhibited the formation of advanced glycation end products (AGEs) in a BSA–fructose model. The results suggest that banana flower could possess the capability in prevention of the diseases associated with abnormal blood sugar and AGEs levels, such as diabetes.  相似文献   

20.
This study reported the chemical composition, phenolic content, antioxidant and anti‐lipase activity of oregano and Lippia essential oils. The major compounds found in oregano essential oil were γ‐terpinene (32.10%), α‐terpinene (15.10%), p‐cymene (8.00%) and thymol (8.00%). In Lippia essential oil, α‐limonene (76.80%) and 1,8‐cineole (4.95%) represented the major compounds. Oregano essential oil had higher phenolic content (12.47 mg gallic acid mL?1) and DPPH scavenging activity (IC50 0.357 μg mL?1) than Lippia essential oil (7.94 mg gallic acid mL?1 and IC50 0.400 μg mL?1, respectively). Both essential oils had similar antioxidant indexes (about 1.2) determined by Rancimat. Moreover, oregano essential oil had also higher anti‐lipase activity (IC50 5.09 and 7.26 μg mL?1). Higher phenolic content in the essential oils was related with higher scavenging and anti‐lipase activities. Oregano and Lippia essential oils could be used as natural antioxidants on food products.  相似文献   

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