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1.
Vitamins are essential compounds to yeasts, and notably in winemaking contexts. Vitamins are involved in numerous yeast metabolic pathways, including those of amino acids, fatty acids, and alcohols, which suggests their notable implication in fermentation courses, as well as in the development of aromatic compounds in wines. Although they are major components in the course of those microbial processes, their significance and impact have not been extensively studied in the context of winemaking and wine products, as most of the studies focusing on the subject in the past decades have relied on relatively insensitive and imprecise analytical methods. Therefore, this review provides an extensive overview of the current knowledge regarding the impacts of vitamins on grape must fermentations, wine-related yeast metabolisms, and requirements, as well as on the profile of wine sensory characteristics. We also highlight the methodologies and techniques developed over time to perform vitamin analysis in wines, and assess the importance of precisely defining the role played by vitamins in winemaking processes, to ensure finer control of the fermentation courses and product characteristics in a highly complex matrix.  相似文献   

2.
Randomly selected domestic and export shipments (n = 1907) of Canadian durum and other wheat that occurred between 1 January 2010 and 31 December 2012 were analysed for ochratoxin A (OTA). The majority of samples did not contain OTA above the LOQ of 1 μg kg–1. Only 37% of samples analysed contained quantifiable OTA; the median OTA of the positive results was 2.10 μg kg–1. Canada Western Amber Durum shipments contained OTA more frequently, and at slightly higher concentrations, than Canada Western Red Spring wheat. For both wheat classes the frequency of OTA occurrence and mean concentrations appeared to increase in the lower grades, but these increases were not statistically significant. A periodic trend of a late summer increase of mean monthly OTA concentrations in shipments appears tied to the cycle of producer deliveries of wheat to primary grain elevators.  相似文献   

3.
An LC-MS/MS multi-method was developed to simultaneously quantify ergot alkaloids (EAs) and tropane alkaloids (TAs) in 113 cereal-based food for infants and young children. To assess yearly variation, samples were collected in 2011, 2012 and 2014. EAs were detected in 54% and TAs in 22% of the samples. Mean EA levels in the three sampling years were 10.6, 6.2 and 8.6 µg kg?1, respectively (maximum: 115.4 µg kg?1), indicating that exposure to EAs would not have exceeded the health-based guidance values set by EFSA in 2012. Mean TA levels were 3.9, 2.4 and 0.4 µg kg?1, respectively (maximum: 80.8 µg kg?1). The acute reference dose for TAs, derived by EFSA in 2013, would have been exceeded by young children when consuming some of the products sampled in 2011–2012. TA levels had decreased drastically in 2014, possibly due to measures taken by producers as response to the EFSA Opinion.  相似文献   

4.
A method based on high-performance liquid chromatography (HPLC) with fluorescence (FL) detection for the simultaneous analysis of phytosterols (stigmasterol, β-sitosterol, campesterol, ergosterol, and fucosterol) and cholesterol was developed. To fluoresceinate the sterols, they were derivatized by 1-anthroyl cyanide to the hydroxyl group at carbon 3 of each sterol skeleton. This HPLC-FL method consists of a C-30 column, an isocratic solution using acetone/acetonitril/hexane/water (71:20:4:5, v/v) as the mobile phase at 1.0 mL min?1 and fluorescence detection at an excitation of 370 nm and an emission of 470 nm. The separation of five phytosterols, cholesterol, and 1-hexacosanol as an internal standard was achieved with sufficient reproducibility and quantitative ability. Our method could evaluate the sterols of land plants such as wood ear fungus, soybean, and parsley, as well as marine algae such as Hiziki (Phaeophyta), Ogonori (Rhodophyta), and Heraiwazuta (Chlorophyta). As a result of the analysis of land plants, wood ear contained a large amount of ergosterol as a precursor of vitamin D2. Soybean contained a large amount of stigmasterol, campesterol, and β-sitosterol. Parsley contained small amounts of these sterols compared with wood ear and soybean. Among the marine algae, Hiziki, Ogonori, and Heraiwazuta contained large amounts of fucosterol, cholesterol, and β-sitosterol, respectively. The compositions of marine algae differed from those of land plants.  相似文献   

5.
In the present study, a sensitive, rapid, and simple method for determination of furanic compounds in baby foods has been developed. Headspace liquid-phase microextraction (HS-LPME) coupled with gas chromatography–mass spectrometry was used to extract and measure furan, 2-methylfuran, and 2,5-dimethylfuran in baby foods. Effective parameters such as salt amount (NaCl), stirring rate, temperature, and time of extraction were optimized using response surface methodology based on a central composite design to obtain the best conditions for extracting furanic compounds. The optimum parameter values were 1 g NaCl, 700 rpm stirring rate, 40 °C extraction temperature, and 15 min extraction time. The calibration curves were linear over the range of 0.2–200 ng?mL?1 (R 2 ?>?0.99) for all compounds, and the repeatability of the method, described as relative standard deviation, ranged between 3.84 and 7.06 % (n?=?6). The recovery of spiked baby food sample after extraction ranged between 89.33 and 103.64 %, and the best enrichment factor was achieved about 972-fold for furan. The limits of detection and quantitation ranged between 0.021 and 0.038 ng?g?1 and 0.069 and 0.126 ng?g?1, respectively. The merit figures of the HS-LPME/GC-MS method showed that it can be considered as a new, fast, and effective alternative method for investigating furanic compounds in baby foods.  相似文献   

6.
Food Science and Biotechnology - Benzyl chloride is a harmful chemical that contaminates air, water, and food. A static headspace GC–MS method for determining benzyl chloride in food was...  相似文献   

7.
A method based on high-performance liquid chromatography with fluorescence detection for the simultaneous analysis of retinoids (vitamin A) and tocopherols (vitamin E) was developed. This method consists of an isocratic solution using hexane/ethyl acetate (85:15, v/v) as the mobile phase and fluorescence detection using a time program that sets the excitation (Ex) and emission (Em) wavelengths at adequate elution times for retinoids (Ex 342 nm, Em 476 nm) and tocopherols (Ex 298 nm, Em 325 nm), respectively. The separation of three retinoids (retinyl palmitate, retinyl acetate, and free retinol) and four tocopherol homologs was achieved with sufficient reproducibility and quantitative ability. Additionally, the necessity of saponification was considered. As a result, saponification was not used in this method because of the complexity of the procedure and the loss of free retinol. The retinoid and tocopherol contents of various foods were evaluated using the developed method. Our method could evaluate the retinoid and tocopherol contents of fish (eel, Anguilla japonica, and amberjack, Seriola dumerili) muscle and liver, roasted soybean (Glycine max) flour, and Japanese torreya seed (Torreya nucifera). Additionally, our method could be applied to the determination of retinoids and tocopherols not only in foods but also in supplements and cosmetics.  相似文献   

8.
Pearl millet is one of the most important food staples of poorer populations in the drylands of India. To better understand the potential market for high-iron, pearl millet hybrids, we explored factors associated with growing pearl millet, and those that influence whether farmers grow major (popular) hybrids, as compared with minor cultivars in the State of Maharashtra. We tested the relationships among cultivar choice, seed source, and information sources. The data confirm that pearl millet is more likely to be grown by poorer households in drier, drought-prone areas. Scheduled castes are more likely to grow popular hybrids, and less likely to grow minor cultivars, but are no less likely to acquire seed from commercial vendors than less privileged people. Farmers who ascribe more importance to consumption attributes are more likely to grow minor than popular hybrids. De facto, popular pearl millet varieties are likely to reach less privileged farmers. To attain adoption potential, popular hybrids could be targeted for iron enrichment, and commercial marketing strategies should be pursued with diversified public and private sector partnerships.  相似文献   

9.
A headspace-solid phase micro-extraction (HS-SPME) GC–MS method has been developed for the determination of coumarin, vanillin and ethyl vanillin in vanilla products. Limits of detection ranged from 1.33 to 13.2 ng mL−1. Accuracy and precision data for the method were measured and compared to those obtained using LC-ESI-MS. A survey of 24 commercially available vanilla products was completed using both techniques. No coumarin was detected in any of the samples. Examination of the GC–MS chromatograms revealed the presence of 18 other flavor related compounds in the samples. The method validation and sample analysis data using HS-SPME-GC–MS were comparable to those obtained using the LC–MS method. Because the two methods are conceptually different from one another, both methods would not be subject to the same interferences. This would allow them to be used as confirmatory methods for each other.  相似文献   

10.
An improved and highly sensitive method was developed and validated for the determination of 12 (7 permitted and 5 non-permitted in Korea) non-nutritive sweeteners in various foods using liquid chromatography-electrospray ionisation-tandem mass spectrometry. The chromatographic separation was performed on an Xbridge BEH C18 column (3 mm × 100 mm, 2.5 μm) with gradient elution using 10 mM ammonium acetate in water and 10 mM ammonium acetate in methanol. Sample preparation consisted of simple dilution, homogenisation, centrifugation and purification with a C18 cartridge prior to analysis. The relative matrix effect (%ME) was within ±20% for all sweeteners. The method also showed good linearity (R2 > 0.99). The limit of detection and limit of quantification values in sample were in the range of 0.02–2.66 and 0.06–8.05 mg kg?1, respectively. The recoveries at three concentration levels ranged between 80% and 119%, with relative standard deviation values below 10%. In addition, the expanded uncertainties determined for 12 sweeteners in 5 different food matrices were confirmed to be <14%. Finally, the method was successfully applied to the analysis of sweeteners in 681 food samples purchased in Korea, Australia and Turkey. These results demonstrate that the method is suitable for the simultaneous determination of multiple-sweeteners in a variety of foods.  相似文献   

11.
Though olive oil is a perishable product, there is not a European regulation for maximum consumption time after production, in part because its durability depends on the storage conditions. The main objectives of this study were to compare the influence of the type of storage on changes of Portuguese virgin olive oils and to verify whether the addition of Catostylus tagi could increase the oxidative stability of olive oil. Over 12 months, the conservation status of monovarietal and blended olive oils in four contexts possible to be used by the consumer was monitored. The analyzed parameters were chlorophyll content, free acidity, peroxide value, specific extinction coefficients at 232 and 270 nm and delta K. Spaced determinations of iodine index and total tocopherol contents complemented the study. Results showed that at Mediterranean temperatures and normal storage procedure, the mean time to reach maximum peroxides value was 12–13 months. At artificial light storage, C. tagi was effective in reducing peroxides evolution by 11 %.  相似文献   

12.
《Food chemistry》2001,75(1):101-108
A simple, rapid and accurate GC analytical method for direct quantification of short-chain volatile organic acids in liquid foods was established. Hydrophilic 1,3-butanediol was selected as the internal standard. Thirteen volatile organic acids including acetic, propionic, isobutyric, butyric, isovaleric, valeric, caproic, heptanoic, caprylic, capric, lauric, lactic and levulinic acids were simultaneously determined with detection limits 0.025–1 ng . The recovery rates of tested acids from fruit juice and vinegar were 92–109% with coefficients of variation below 9.4%. The contents of volatile organic acids in 37 commercial liquid food samples were determined.  相似文献   

13.
Surveys were carried out between 2007 and 2010 to determine the total levels of sulfites in 1245 samples of wines, dried apricots, dried vegetables, nuts, juices and purees, frozen foods and cereals containing dried fruit supplied by food inspectors and by food producers for testing or for export certification. Sulfite analysis of wine was carried out using the Ripper method with an LOQ of 5?mg?l?1 and for dried and other foods the Monier-Williams distillation procedure was employed with an LOQ of 10?mg?kg?1. In the survey all wines contained measurable sulfites, but with the exception of one sample of white wine they were otherwise below Turkish Food Codex limits of 160?mg?kg?1 for red wine, 210?mg?kg?1 to white wine and 235?mg?kg?1 for sparkling wine. None of the cereal products, frozen foods, juices or purees contained sulfites above 10?mg?kg?1. However, all dried apricot samples contained significant levels of sulfite with around 40% having levels exceeding the Turkish limit of 2000?mg?kg?1. Significant levels of sulfite were found in other samples of dried fruit with even a fruit and nut bar containing 1395?mg?kg?1 of sulfite, suggesting the dried fruit ingredients contained levels above regulatory limits.  相似文献   

14.
The objective of this study was to implement an in vitro–produced embryo transfer (IVP-ET) system in an existing stochastic dynamic dairy simulation model with multitrait genetics to evaluate the genetic, technical, and financial performance of a dairy herd implementing an exclusive IVP-ET or artificial insemination (AI) system. In the AI system, sexed semen was used on the genetically best heifers only. In the IVP-ET system, all of the animals in the herd were impregnated with female sexed embryos created through in vitro fertilization of oocytes collected from animals of superior genetics for different traits of interest. Each donor was assumed to yield on average 4.25 transferable embryos per collection. The remaining animals in the herd were used as recipients and received either a fresh embryo or a frozen embryo when fresh embryos were not available. Selection of donors was random or based on the greatest estimated breeding value (EBV) of lifetime net merit (NM$), milk yield, or daughter pregnancy rate. For both the IVP-ET and AI systems, culling of surplus heifer calves not needed to replace culled cows was based on the lowest EBV for the same traits. A herd of 1,000 milking cows was simulated 15 yr over time after the start of the IVP-ET system. The default cost to produce and transfer 1 embryo was set at $165. Prices of fresh embryos at which an exclusive IVP-ET system financially breaks even with the comparable AI system in yr 15 and for an investment period of 15 yr were also estimated. More surplus heifer calves were sold from the IVP-ET systems than from the comparable AI systems. The surplus calves from the IVP-ET systems were also genetically superior to the surplus calves from the comparable AI systems, which might be reflected in their market value as a premium price. The most profitable scenario among the 4 IVP-ET scenarios in yr 15 was the one in which NM$ was maximized in the herd. This scenario had an additional profit of $8/cow compared with a similar AI scenario that maximized NM$, provided that surplus heifer calves could be sold at a premium price based on the superiority of the EBV of NM$. For the IVP-ET system to be at least as profitable as the comparable AI system during a 15-yr investment period, the surplus calves from the IVP-ET system needed to be sold at the premium prices. The break-even price of fresh embryos was estimated to be $84 for the exclusive IVP-ET system. This resulted in the same profit as the AI system, which maximized NM$ for a 15-yr investment period and in which heifer calves were sold at a premium price.  相似文献   

15.
16.
A method for rapid and sensitive determination of melamine in aquatic products by gas chromatography–mass spectrometry with microwave-assisted derivatization was proposed in this paper. Melamine was extracted from aquatic product samples using methanol, and the extract was cleaned with a mixed-mode cationic exchange solid phase extraction column. After elution with 5 % ammonia–methanol solution and drying with nitrogen, the residue was derivatized using N,O-bis(trimethylsilyl)trifluoroacetamide containing 1 % trimethylchlorosilane under microwave irradiation for 1 min with a power of 420 W, then detected with gas chromatography–mass spectrometry, and quantified by the external standard method. Some important parameters such as extraction solvent, microwave irradiation power and time, and derivatization reagent volume were investigated and optimized. The results showed that methanol could effectively extracted melamine from aquatic products as well as precipitated the protein in samples. Under the optimum conditions, the detection limit for melamine was as low as 0.006 mg/kg, and the linear range was from 0.02 to 50 mg/kg with a correlation coefficient of 0.9997. The proposed method was applied to the analysis of melamine in aquatic products (fish, shrimp, clam, and winkle), and the recovery for melamine was 89.65–105.16 % with relative standard deviation of 3.0–6.0 %.  相似文献   

17.
A new farm economic typology has recently been introduced in the EU. This study compares the economic performance of wine-grape growers in four important quality wine areas of Sicily taking into account the different EU economic typology standards of standard gross margin (the old method) and standard output (the new method). The objective of this study is to identify the differences between the two methods and to ascertain the potential implications for small wine-grape growers’ profitability and their access to public support. We seek to determine whether restrictions can be identified that limit the potential benefits from rural development policies.

For this purpose, we applied the economic criteria of the EU to a representative sample of Sicilian wine-grape growers in order to compare the economic profitability of wine-grape farms in protected designation of origin areas. This comparative approach has allowed us to categorize the economic size of the sample in accordance with recent EU modifications and discuss the possible impacts that the adoption of the new economic criteria would have on access to the Rural Development Programme measures for wine-grape growers.  相似文献   


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In this study, we established a rapid and sensitive method for the detection of viable Salmonella Typhimurium, Staphylococcus aureus, and Listeria monocytogenes in milk using biotin-exposure-based immunomagnetic separation (IMS) combined with sodium dodecyl sulfate (SDS), propidium monoazide (PMA), and multiplex real-time PCR (mRT-PCR). We used IMS to lessen the assay time for isolation of target bacteria. We then optimized the coupling conditions and immunomagnetic capture process. The immunoreaction and incubation times for 5 μg of mAb coupled with 500 μg of streptavidin-functionalized magnetic beads using a streptavidin-biotin system were 90 and 30 min, respectively. Treatment with SDS-PMA before mRT-PCR amplification eliminated false-positive outcomes from dead bacteria and identified viable target bacteria with good sensitivity and specificity. The limit of detection of IMS combined with the SDS-PMA-mRT-PCR assay for the detection of viable Salmonella Typhimurium, Staph. aureus, and L. monocytogenes in spiked milk matrix samples was 10 cfu/mL and remained significant even in the appearance of 106 cfu/mL of nontarget bacteria. The entire detection process was able to identify viable bacteria within 9 h. The combination of biotin-exposure-mediated IMS and SDS-PMA-mRT-PCR has potential value for the rapid and sensitive detection of foodborne pathogens.  相似文献   

20.
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