Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 87
Filtrar
Más filtros










Intervalo de año de publicación
1.
Food Chem ; 399: 133979, 2023 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-35998494

RESUMEN

The changes of capsaicinoids in the pericarp and placenta of Jeromin pepper fruits, collected at two different stages of plant's maturity (young and adult), has been studied throughout the ripening process. This variety is used in the production of "Pimentón de La Vera" and recognized under a Protected Designation of Origin, so it is of great importance to determine their optimum harvesting time to get the most of its beneficial health effects. Capsaicinoids reached the maximum concentration on the 30th days post-anthesis (dpa) for the young plant, while in the adult plant it was later, specifically on 40th and 60th dpa for the placenta and pericarp, respectively. From this moment on, a sharp decrease in their content is observed. In addition, higher amounts of total capsaicinoids have been found in the second stage of plant maturity with respect to the first one, both in the placenta and in the pericarp.


Asunto(s)
Capsicum , Piper nigrum , Capsaicina/análisis , Frutas/química
2.
Foods ; 11(14)2022 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-35885391

RESUMEN

Tryptophan (Trp) is an essential amino acid usually found in fruit juices. Its determination is necessary for food companies because of its relation to human health. In this work, a new electrochemical method based on sonogel-carbon electrodes (SNGCEs) was developed and validated using an ultra performance liquid chromatography (UPLC) method as a reference method for the determination of Trp in fruit juices. Cyclic voltammetry (CV), chronoamperometry, and differential pulse voltammetry (DPV) techniques were applied to investigate the oxidation of Trp on a previously polarized SNGCE surface in a Britton-Robinson (BR) buffer solution at pH 3.6. The operating conditions for electroanalysis were optimized using a Box-Behnken design (BBD), obtaining an oxidation peak for Trp at 0.749 V. The linear range for this method was from 0.1 to 5 mg/L. The intraday and interday precision, expressed as a relative standard deviation (RSD), were 3.1% and 2.7%, respectively. The average recovery was 99.01%, and the limit of detection and quantitation were 0.33 and 1.09 mg/L, respectively. Therefore, from the quality analytical parameters obtained, it can be concluded that the new electrochemical method can be successfully used for the routine analysis of Trp in fruit juices. As far as we are concerned, this is the first time that a methodology for Trp determination was performed in this kind of real food matrices.

3.
J Fungi (Basel) ; 8(6)2022 Jun 02.
Artículo en Inglés | MEDLINE | ID: mdl-35736081

RESUMEN

Hallucinogenic fungi, mainly those from the Psilocybe genus, are being increasingly consumed even though there is no control on their culture conditions. Due to the therapeutic potential as antidepressants and anxiolytics of the alkaloids that they produce (psilocin and psilocybin), some form of control on their production would be highly recommended. Prior to identifying their optimal culture condition, a methodology that allows their study is required. Microwave-assisted extraction method (MAE) is a technique that has proven its efficiency to extract different compounds from solid matrices. For this reason, this study intends to optimize a MAE method to extract the alkaloids found in Psylocibe cubensis. A surface-response Box-Behnken design has been employed to optimize such extraction method and significantly reduce time and other resources in the extraction process. Based on the Box-Behnken design, 50 °C temperature, 60% methanol as extraction solvent, 0.6 g:10 mL sample mass:solvent ratio and 5 min extraction time, were established as optimal conditions. These mild conditions, combined with a rapid and efficient UHPLC analysis result in a practical and economical methodology for the extraction of psilocin and psilocybin from Psylocibe cubensis.

4.
Foods ; 11(12)2022 Jun 17.
Artículo en Inglés | MEDLINE | ID: mdl-35741980

RESUMEN

The transfer of aromatic compounds from the grape skins to the musts has been studied using a process involving freezing whole bunches or crushed grapes for winemaking the Muscat of Alexandria variety (white wine). Subsequently, a prefermentative maceration has been applied to some of the samples. The aromatic profiles of the final wines have been determined using gas chromatography coupled to mass spectrophotometry (GC-MS). The results revealed that, in the trials in which whole grapes were frozen, the final wines had a higher aromatic concentration compared to that of wines obtained by either freezing crushed grapes or obtained with traditional winemaking techniques. Thus, the wines produced from frozen whole grapes were found to exhibit different characteristics from the rest of the wines. The compounds affected by the freezing either of the whole bunches or the crushed grapes were terpenes, acids, and esters. Lower differences were found for wines produced applying prefermentative maceration after the freezing process.

5.
Food Chem X ; 13: 100192, 2022 Mar 30.
Artículo en Inglés | MEDLINE | ID: mdl-35498970

RESUMEN

Blackcurrant (Ribes nigrum L.) is a fruit rich in vitamins, fatty acids, minerals, essential oils and phenolic compounds, including anthocyanins. In the present work, two anthocyanin extraction methods from blackcurrant samples based on Ultrasound-Assisted Extraction (UAE) and Enzyme-Assisted Extraction (EAE) have been developed. A Plackett-Burman design with seven variables has been preliminary used for both UAE and EAE in order to determine the most influential variables in each methodology. After that, a Box-Behnken design was employed to optimize the extraction methods. The composition of the extraction solvent (% EtOH in water) has been the most influential variable for both UAE and EAE. The optimal extraction times have been 5 min for UAE and 10 min for EAE. No differences have been observed in anthocyanin extraction with both methodologies. Both methods have been applied to blackcurrant-derived products and proven their suitability for quality control analysis.

6.
Antioxidants (Basel) ; 11(5)2022 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-35624711

RESUMEN

Despite the excellent beneficial properties that anthocyanins and total phenolic compounds give to the red onion bulbs, few articles have investigated modern extraction techniques or experimental designs in this field. For this reason, the present study proposes the development and optimization of alternative methods for the extraction of these compounds based on microwave-assisted extraction and the Box-Behnken experiment design. The optimal values for the extraction of total anthocyanins have been established at 62% methanol composition as a solvent, pH 2, 56 °C temperature, and 0.2:13 g:mL sample-solvent ratio. Regarding the extraction of total phenolic compounds, the optimal conditions have been established at 100% pure methanol as a solvent with pH 2, 57 °C temperature, and 0.2:8.8 g:mL sample-solvent ratio. Short extraction times (min), good recoveries (mg of bioactive compound g-1 of dry onion), and high repeatability and intermediate precision (coefficient of variation (%)) have been confirmed for both methods. Regarding total anthocyanins, the following results have been obtained: 2 min, 2.64 ± 0.093 mg of total anthocyanins g-1 of dry onion, and 2.51% and 3.12% for precision. Regarding phenolic compounds, the following results have been obtained: 15 min, 7.95 ± 0.084 mg of total phenolic compound g-1 of dry onion, and 3.62% and 4.56% for precision. Comparing these results with those of other authors and with those obtained in a previous study of ultrasound-assisted extraction, it can be confirmed that microwave-assisted extraction is a quantitative, repeatable, and very promising method for the extraction of phenolic compounds and anthocyanins, which offers similar and even superior results with little solvent expense, time, and costs.

7.
Sensors (Basel) ; 22(10)2022 May 19.
Artículo en Inglés | MEDLINE | ID: mdl-35632260

RESUMEN

Fruit juice production is one of the most important sectors in the beverage industry, and its adulteration by adding cheaper juices is very common. This study presents a methodology based on the combination of machine learning models and near-infrared spectroscopy for the detection and quantification of juice-to-juice adulteration. We evaluated 100% squeezed apple, pineapple, and orange juices, which were adulterated with grape juice at different percentages (5%, 10%, 15%, 20%, 30%, 40%, and 50%). The spectroscopic data have been combined with different machine learning tools to develop predictive models for the control of the juice quality. The use of non-supervised techniques, specifically model-based clustering, revealed a grouping trend of the samples depending on the type of juice. The use of supervised techniques such as random forest and linear discriminant analysis models has allowed for the detection of the adulterated samples with an accuracy of 98% in the test set. In addition, a Boruta algorithm was applied which selected 89 variables as significant for adulterant quantification, and support vector regression achieved a regression coefficient of 0.989 and a root mean squared error of 1.683 in the test set. These results show the suitability of the machine learning tools combined with spectroscopic data as a screening method for the quality control of fruit juices. In addition, a prototype application has been developed to share the models with other users and facilitate the detection and quantification of adulteration in juices.


Asunto(s)
Calidad de los Alimentos , Jugos de Frutas y Vegetales , Control de Calidad , Jugos de Frutas y Vegetales/análisis , Jugos de Frutas y Vegetales/normas , Humanos , Aprendizaje Automático , Espectroscopía Infrarroja Corta
8.
J Fungi (Basel) ; 8(5)2022 May 23.
Artículo en Inglés | MEDLINE | ID: mdl-35628800

RESUMEN

The demand and interest in mushrooms, both cultivated and wild, has increased among consumers in recent years due to a better understanding of the benefits of this food. However, the ability of wild edible mushrooms to accumulate essential and toxic elements is well documented. In this study, a total of eight metallic elements and metalloids (chromium (Cr), arsenic (As), cadmium (Cd), mercury (Hg), lead (Pb), copper (Cu), zinc (Zn), and selenium (Se)) were determined by ICP-MS in five wild edible mushroom species (Agaricus silvicola, Amanita caesarea, Boletus aereus, Boletus edulis, and Russula cyanoxantha) collected in southern Spain and northern Morocco. Overall, Zn was found to be the predominant element among the studied species, followed by Cu and Se. The multivariate analysis suggested that considerable differences exist in the uptake of the essential and toxic elements determined, linked to species-intrinsic factors. Furthermore, the highest Estimated Daily Intake of Metals (EDIM) values obtained were observed for Zn. The Health Risk Index (HRI) assessment for all the mushroom species studied showed a Hg-related cause of concern due to the frequent consumption of around 300 g of fresh mushrooms per day during the mushrooming season.

9.
Artículo en Inglés | MEDLINE | ID: mdl-35329348

RESUMEN

There is high concern about the exposure of firefighters to toxic products or carcinogens resulting from combustion during fire interventions. Firefighter turnout gear is designed to protect against immediate fire hazards but not against chemical agents. Additionally, the decontamination of firefighter personal protective equipment remains unresolved. This study evaluated the feasibility of a screening method based on headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) in combination with chemometrics (cluster analysis, principal component analysis, and linear discriminant analysis) for the assessment of the transference of volatile compounds through turnout gear. To achieve this, firefighter turnout gears exposed to two different fire scenes (with different combustion materials) were directly analyzed. We obtained a spectral fingerprint for turnout gears that were both exposed and non-exposed to fire scenes. The results showed that (i): the contamination of the turnout gears is different depending on the type of fire loading; and (ii) it is possible to determine if the turnout gear is free of volatile compounds. Based on the latest results, we concluded that HS-GC-IMS can be applied as a screening technique to assess the quality of turnout gear prior to a new fire intervention.


Asunto(s)
Bomberos , Incendios , Exposición Profesional , Compuestos Orgánicos Volátiles , Cromatografía de Gases y Espectrometría de Masas , Humanos , Exposición Profesional/análisis , Equipo de Protección Personal , Compuestos Orgánicos Volátiles/análisis
10.
Confl Health ; 16(1): 6, 2022 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-35164807

RESUMEN

BACKGROUND: 'Tele-Mental Health (MH) services,' are an increasingly important way to expand care to underserved groups in low-resource settings. In order to continue providing psychiatric, psychotherapeutic and counselling care during COVID-19-related movement restrictions, Médecins Sans Frontières (MSF), a humanitarian medical organization, abruptly transitioned part of its MH activities across humanitarian and resource-constrained settings to remote format. METHODS: From June-July of 2020, investigators used a mixed method, sequential explanatory study design to assess MSF staff perceptions of tele-MH services. Preliminary quantitative results influenced qualitative question guide design. Eighty-one quantitative online questionnaires were collected and a subset of 13 qualitative follow-up in-depth interviews occurred. RESULTS: Respondents in 44 countries (6 geographic regions), mostly from Sub-Saharan Africa (39.5%), the Middle East and North Africa (18.5%) and Asia (13.6%) participated. Most tele-MH interventions depended on audio-only platforms (80%). 30% of respondents reported that more than half of their patients were unreachable using these interventions, usually because of poor network coverage (73.8%), a lack of communication devices (72.1%), or a lack of a private space at home (67.2%). Nearly half (47.5%) of respondents felt their staff had a decreased ability to provide comprehensive MH care using telecommunication platforms. Most respondents thought MH staff had a negative (46%) or mixed (42%) impression of remote care. Nevertheless, almost all respondents (96.7%) thought tele-MH services had some degree of usefulness, notably improved access to care (37.7%) and time efficiency (32.8%). Qualitative results outlined a myriad of challenges, notably in establishing therapeutic alliance, providing care for vulnerable populations and those inherent to the communications infrastructure. CONCLUSION: Tele-MH services were perceived to be a feasible alternative solution to in-person therapeutic interventions in humanitarian settings during the COVID-19 pandemic. However, they were not considered suitable for all patients in the contexts studied, especially survivors of sexual or interpersonal violence, pediatric and geriatric cases, and patients with severe MH conditions. Audio-only technologies that lacked non-verbal cues were particularly challenging and made risk assessment and emergency care more difficult. Prior to considering tele-MH services, communications infrastructure should be assessed, and comprehensive, context-specific protocols should be developed.

11.
Antioxidants (Basel) ; 10(11)2021 Nov 03.
Artículo en Inglés | MEDLINE | ID: mdl-34829626

RESUMEN

Allium cepa L. is one of the most abundant vegetable crops worldwide. In addition to its versatile culinary uses, onion also exhibits quite interesting medicinal uses. Bulbs have a high content of bioactive compounds that are beneficial for human health. This study intends to develop and optimize two appropriate ultrasound-assisted methods for the extraction of the phenolic compounds and anthocyanins present in red onion. A response surface methodology was employed and, specifically, a Box-Behnken design, for the optimization of the methods. The optimal conditions for the extraction of the phenolic compounds were the follows: 53% MeOH as solvent, pH 2.6, 60 °C temperature, 30.1% amplitude, 0.43 s cycle, and 0.2:11 g sample/mL solvent ratio. On the other hand, the optimal conditions for the anthocyanins were as follows: 57% MeOH as solvent, pH 2, 60 °C temperature, 90% amplitude, 0.64 s cycle, and 0.2:15 g sample/mL solvent ratio. Both methods presented high repeatability and intermediate precision, as well as short extraction times with good recovery yields. These results illustrate that the use of ultrasound-assisted extraction, when properly optimized, is suitable for the extraction and quantification of the compounds of interest to determine and improve the quality of the raw material and its subproducts for consumers.

12.
Antioxidants (Basel) ; 10(9)2021 Aug 28.
Artículo en Inglés | MEDLINE | ID: mdl-34573008

RESUMEN

Purple potato is one of the least known and consumed potato varieties. It is as rich in nutrients, amino acids and starches as the rest of the potato varieties, but it also exhibits a high content of anthocyanins, which confer it with some attractive health-related properties, such as antioxidant, pain-relieving, anti-inflammatory and other promising properties regarding the treatment of certain diseases. A novel methodology based on ultrasound-assisted extraction has been optimized to achieve greater yields of anthocyanins. Optimal extraction values have been established at 70 °C using 20 mL of a 60% MeOH:H2O solution, with a pH of 2.90 and a 0.5 s-1 cycle length at 70% of the maximum amplitude for 15 min. The repeatability and intermediate precision of the extraction method have been proven by its relative standard deviation (RSD) below 5%. The method has been tested on Vitelotte, Double Fun, Highland and Violet Queen potatoes and has demonstrated its suitability for the extraction and quantification of the anthocyanins found in these potato varieties, which exhibit notable content differences. Finally, the antioxidant capacity of these potato varieties has been determined by means of 2,2-diphenyl-1-picrylhydrazyl (DDPH) radical scavenging and the values obtained were similar to those previously reported in the literature.

13.
Foods ; 10(6)2021 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-34207095

RESUMEN

Sherry wine vinegar is a Spanish gourmet product under Protected Designation of Origin (PDO). Before a vinegar can be labeled as Sherry vinegar, the product must meet certain requirements as established by its PDO, which, in this case, means that it has been produced following the traditional solera and criadera ageing system. The quality of the vinegar is determined by many factors such as the raw material, the acetification process or the aging system. For this reason, mainly producers, but also consumers, would benefit from the employment of effective analytical tools that allow precisely determining the origin and quality of vinegar. In the present study, a total of 48 Sherry vinegar samples manufactured from three different starting wines (Palomino Fino, Moscatel, and Pedro Ximénez wine) were analyzed by Fourier-transform infrared (FT-IR) spectroscopy. The spectroscopic data were combined with unsupervised exploratory techniques such as hierarchical cluster analysis (HCA) and principal component analysis (PCA), as well as other nonparametric supervised techniques, namely, support vector machine (SVM) and random forest (RF), for the characterization of the samples. The HCA and PCA results present a clear grouping trend of the vinegar samples according to their raw materials. SVM in combination with leave-one-out cross-validation (LOOCV) successfully classified 100% of the samples, according to the type of wine used for their production. The RF method allowed selecting the most important variables to develop the characteristic fingerprint ("spectralprint") of the vinegar samples according to their starting wine. Furthermore, the RF model reached 100% accuracy for both LOOCV and out-of-bag (OOB) sets.

14.
Foods ; 10(7)2021 Jun 24.
Artículo en Inglés | MEDLINE | ID: mdl-34202620

RESUMEN

This research focuses on the aromatic composition of Muscat of Alexandria wines after the application of ultrasound for 40 or 80 min during a 4 h pre-fermentative maceration process. Two methods of ultrasound application were compared in this study: probe ultrasound and bath ultrasound, for periods of 10-20 min per hour. Increases of more than 200% were obtained for some of the compounds from the skins, such as two of its terpenes, citronellol and nerol. On the other hand, increases in alcohol and ester values were registered with the application of ultrasound for 40 min. However, a significant decrease in these compounds was recorded when the ultrasound process was extended. In fact, when ultrasound was applied for 80 min, content values were even lower than those registered for the wine produced without the application of ultrasound. At the sensory level, the effect resulting from probe and bath ultrasound application for different times were compared, where most of the judges successfully discriminated the wines resulting from the application of ultrasound bath. According to data, the wines resulting from the application of ultrasound bath for 80 min presented the most significant differences, which affected the aromas of white fruit, tropical fruit, stone fruit, flowers and citrus.

15.
Molecules ; 26(11)2021 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-34073913

RESUMEN

Sweeteners have been used in food for centuries to increase both taste and appearance. However, the consumption of sweeteners, mainly sugars, has an adverse effect on human health when consumed in excessive doses for a certain period, including alteration in gut microbiota, obesity, and diabetes. Therefore, the application of non-nutritive sweeteners in foodstuffs has risen dramatically in the last decade to substitute sugars. These sweeteners are commonly recognized as high-intensity sweeteners because, in a lower amount, they could achieve the same sweetness of sugar. Regulatory authorities and supervisory agencies around the globe have established the maximum amount of these high-intensity sweeteners used in food products. While the regulation is getting tighter on the market to ensure food safety, reliable analytical methods are required to assist the surveillance in monitoring the use of high-intensity sweeteners. Hence, it is also necessary to comprehend the most appropriate method for rapid and effective analyses applied for quality control in food industries, surveillance and monitoring on the market, etc. Apart from various analytical methods discussed here, extraction techniques, as an essential step of sample preparation, are also highlighted. The proper procedure, efficiency, and the use of solvents are discussed in this review to assist in selecting a suitable extraction method for a food matrix. Single- and multianalyte analyses of sweeteners are also described, employing various regular techniques, such as HPLC, and advanced techniques. Furthermore, to support on-site surveillance of sweeteners' usage in food products on the market, non-destructive analytical methods that provide practical, fast, and relatively low-cost analysis are widely implemented.


Asunto(s)
Análisis de los Alimentos/métodos , Edulcorantes no Nutritivos/análisis , Técnicas de Química Analítica/métodos
16.
Molecules ; 26(10)2021 May 13.
Artículo en Inglés | MEDLINE | ID: mdl-34068086

RESUMEN

Erica australis plants have been used in infusions and folk medicine for years for its diuretic and antiseptic properties and even for the treatment of infections. In addition, a recently published thorough study on this species has demonstrated its antioxidant, antibiotic, anti-inflammatory, anticarcinogenic and even antitumoral activities. These properties have been associated with the high content of anthocyanins in E. australis leaves and flowers. The aim of the present research is to optimize an ultrasound-assisted extraction methodology for the recovery of the anthocyanins present in E. australis flowers. For that purpose, a Box Behnken design with response surface methodology was employed, and the influence of four variables at different values was determined: namely, the composition of the extraction solvents (0-50% MeOH in water), the pH level of those solvents (3-7), the extraction temperature (10-70 °C), and the sample:solvent ratio (0.5 g:10 mL-0.5 g:20 mL). UHPLC-UV-vis has been employed to quantify the two major anthocyanins detected in the samples. The extraction optimum conditions for 0.5 g samples were: 20 mL of solvent (50% MeOH:H2O) at 5 pH, with a 15 min extraction time at 70 °C. A precision study was performed and the intra-day and inter-day relative standard deviations (RSDs) obtained were 3.31% and 3.52%, respectively. The developed methodology has been successfully applied to other Erica species to validate the suitability of the method for anthocyanin extraction.


Asunto(s)
Antocianinas/análisis , Ericaceae/química , Flores/química , Ultrasonido/métodos , Cromatografía Líquida de Alta Presión , Metanol/química , Estándares de Referencia , Temperatura , Factores de Tiempo
17.
Foods ; 10(5)2021 May 11.
Artículo en Inglés | MEDLINE | ID: mdl-34064824

RESUMEN

This study presents the effects of different working temperatures on the transfer of compounds during the pre-fermentative and fermentative stages of the wine making process with 'Cabernet Sauvignon' grapes. Two different procedures have been evaluated. Firstly, the pre-fermentative maceration of the crushed grapes at two different temperatures (20 °C and 10 °C). Then, the alcoholic fermentation under two different sets of conditions, the fermentation at a constant temperature of 20 °C and the fermentation under a positive temperature gradient from 10 to 20 °C. According to the experimental results, the phenolic contents (total phenolics, total anthocyanins, and total tannins) were mainly conditioned by the fermentation temperature, however the pre-fermentative conditions also affected the content levels of these compounds. Furthermore, the use of a fermentation temperature gradient improved the organoleptic characteristics of the wines. However, the color was not as stable as that of wines produced through fermentation at a higher constant temperature. Consequently, the implementation of a temperature gradient during the alcoholic fermentation process is recommended and a longer period at high temperature over the last phase of the process would be desirable to obtain aromatic wines with the desirable color stability.

18.
Food Chem ; 356: 129688, 2021 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-33812187

RESUMEN

Capsaicinoids and capsinoids compounds have been a focus of special attention for their health benefits. An effective and rapid Ultra-High-Performance Liquid Chromatography (UHPLC-PDA) method has been developed and validated for the simultaneous separation and quantitative determination of the major capsaicinoids and capsinoids present in peppers. The separation of all the compounds of interest was achieved in less than 2 min by means of an ACQUITY UPLC BEH rp-C18 column (100 mm × 2.1 mm i.d., 1.7 µm particle size). The variables that have been optimized are the mobile phase (water as solvent A and acetonitrile as solvent B, both acidified by adding 0.1% acetic acid), separation gradient, column temperature (35-70 °C), flow rate (0.6-0.95 mL min-1), and injection volume (2.5-3.5 µL). The evaluation of the chromatographic performance revealed excellent resolution, retention factor, and selectivity. The method was satisfactorily validated in terms of linearity, detection and quantification limits, precision, and robustness.


Asunto(s)
Capsaicina/análogos & derivados , Capsaicina/análisis , Capsicum/química , Cromatografía Líquida de Alta Presión/métodos , Capsicum/metabolismo , Límite de Detección , Espectrometría de Masas/métodos , Reproducibilidad de los Resultados , Temperatura
19.
Sensors (Basel) ; 21(6)2021 Mar 19.
Artículo en Inglés | MEDLINE | ID: mdl-33808571

RESUMEN

The objective of the present study is to develop an optimized method where headspace-ion mobility spectrometry is applied for the detection and discrimination between four petroleum-derived products (PDPs) in water. A Box-Behnken design with a response surface methodology was used, and five variables (incubation temperature, incubation time, agitation, sample volume, and injection volume) with influences on the ion mobility spectrometry (IMS) response were optimized. An IMS detector was used as a multiple sensor device, in which, each drift time acts as a specific sensor. In this way, the total intensity at each drift time is equivalent to multiple sensor signals. According to our results, 2.5 mL of sample incubated for 5 min at 31 °C, agitated at 750 rpm, and with an injection volume of 0.91 mL were the optimal conditions for successful detection and discrimination of the PDPs. The developed method has exhibited good intermediate precision and repeatability with a coefficient of variation lower than 5%, (RSD (Relative Standard Deviation): 2.35% and 3.09%, respectively). Subsequently, the method was applied in the context of the detection and discrimination of petroleum-derived products added to water samples at low concentration levels (2 µL·L-1). Finally, the new method was applied to determine the presence of petroleum-derived products in seawater samples.

20.
Pharmaceuticals (Basel) ; 14(4)2021 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-33915768

RESUMEN

Onion, one of the most consumed vegetables in the world, is also known to contain high levels of antioxidant compounds, with protective effects against different degenerative pathologies. Specifically, onion is rich in flavonols, mainly quercetin derivatives, which are compounds with high antioxidant and free radical scavenging power. For this reason, it is of the utmost importance to count on optimal analytical methods that allow for the determination and quantification of these compounds of interest. A rapid ultra-high performance liquid chromatography (UHPLC)-photo-diode array (PDA) method for the separation of the major flavonols in onions was developed using a Box-Behnken design in conjunction with multiresponse optimization on the basis of the desirability function. The conditions that provided a successful separation were 9.9% and 53.2% of phase B at the beginning and at the end of the gradient, respectively; 55 °C column working temperature; and 0.6 mL min-1 flow rate. The complete separation was achieved in less than 2.7 min with excellent chromatographic characteristics. The method was validated, and its high precision, low detection and quantification limits, good linearity, and robustness were confirmed. The correct applicability of the method improves the analysis of the raw material, increasing the quality of onions and its subproducts in terms of bioactive compounds and functional characteristics for consumers.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...