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1.
Int J Biol Macromol ; 253(Pt 5): 127167, 2023 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-37793535

RESUMEN

A chitosan-glucose derivative (ChG) with lower antimicrobial activity against whey native probiotic yeast K. marxianus VM004 was synthesized by the Maillard reaction. The ChG derivative was characterized by FT-IR, 1H NMR, and SLS to determine the structure, deacetylation degree (DD), and molecular weight (Mw). In addition, we evaluated the antioxidant, cytotoxic, and antimicrobial activities of ChG. ChG was then used for microencapsulation of K. marxianus VM004 by spray drying. The microcapsules were characterized by evaluating their encapsulation yield, encapsulation efficiency, morphology, tolerance to the gastrointestinal tract, and viability during storage. The results indicated that a non-cytotoxic product with lower MW and DD and higher antioxidant activity than native chitosan was obtained by the Maillard reaction. The yeast ChG microcapsules exhibited an encapsulation efficiency >57 %, improved resistance to gastrointestinal conditions, and enhanced stability during storage. These results demonstrate that ChG may be a promising wall material for the microencapsulation of probiotic yeasts.


Asunto(s)
Antiinfecciosos , Quitosano , Probióticos , Quitosano/farmacología , Quitosano/química , Cápsulas/química , Espectroscopía Infrarroja por Transformada de Fourier , Antioxidantes , Antiinfecciosos/farmacología
2.
Einstein (Sao Paulo) ; 20: eRC6903, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36000615

RESUMEN

Prune belly syndrome is a rare congenital disease of unknown etiology that is present in one in every 40 thousand live births, and predominantly affects males, at a ratio of 4:1. In males, it presents with anomalies in the urinary system, absence of abdominal muscles, bilateral cryptorchidism, and infertility. In women, the syndrome has variable presentations, but fertility is preserved. Searching the medical literature, we found only one case of prune belly syndrome in pregnant women. Therefore, the patient in this report is the second case. She was primiparous, 25-years-old, with no abdominal muscles, severe congenital kyphoscoliosis, and pulmonary restriction. Elective cesarean section was performed at 37 weeks of gestation due to maternal risk of uterine rupture by transverse presentation and fetal risk of intrauterine growth restriction. The pre-anesthetic approach defined that general anesthesia might have more risks for the patient due to severe maternal lung disease compared to ultrasound-guided locoregional anesthesia. During prenatal care, there were some maternal complications, such as asthma exacerbations, abdominal pain, and constipation. The newborn was born small for gestational age and this can possibly be explained by maternal restrictive lung capacity. The newborn presented with Apgar score 8/9 and tachypnea, but improved after two hours of life.


Asunto(s)
Criptorquidismo , Síndrome del Abdomen en Ciruela Pasa , Músculos Abdominales , Adulto , Cesárea , Femenino , Humanos , Recién Nacido , Masculino , Embarazo , Síndrome del Abdomen en Ciruela Pasa/complicaciones , Síndrome del Abdomen en Ciruela Pasa/diagnóstico por imagen , Ultrasonografía
3.
FEMS Microbiol Lett ; 369(1)2022 04 21.
Artículo en Inglés | MEDLINE | ID: mdl-35325116

RESUMEN

Bacteriocins from Gram-positive bacteria have been proposed as natural food preservative and there is a need for large-scale production for commercial purposes. The aim of the present work is to evaluate whey, a cheese industrial by-product, for the production and microencapsulation of enterocin CRL35. Whey proved to be a promising basal medium for bacterial growth although the bacteriocin production was quite low. However, it could be much favored with the addition of yeast extract at concentrations as low as 0.5%. Besides improving bacteriocin production, this peptide was successfully microencapsulated by spray drying using whey protein concentrate and a chitosan derivative as wall materials. Microcapsules averaging 10 ± 5 µm diameter were obtained, with good structural integrity and high antimicrobial activity with a stability of at least 12 weeks at 4°C. In summary, sustainable bacteriocin production and microencapsulation was achieved recycling whey or its derivatives. In addition, the formulation owns high antimicrobial activity with a long shelf life. The development of a food preservative may represent a green solution for handling whey.


Asunto(s)
Bacteriocinas , Conservantes de Alimentos , Antibacterianos/farmacología , Bacteriocinas/metabolismo , Productos Lácteos , Conservantes de Alimentos/farmacología
4.
Food Chem ; 381: 132250, 2022 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-35121321

RESUMEN

Peanuts contain a diverse and vast array of phenolic compounds having important biological properties. They are allocated mostly in the seed coat (skin), an industrial waste with minor and undervalued applications. In the last few years, a considerable amount of scientific knowledge about extraction, composition, bioactivities and health benefits of peanut skin phenolics has been generated. The present review was focused on four main aspects: a) extraction methods and technologies for obtaining peanut skin phenolics with an emphasis on green-solvent extraction processes; b) variations in chemical profiles including those due to genetic variability, extraction methodologies and process-related issues; c) bioactive properties, especially antioxidant activities in food and biological systems; d) update of promising food applications. The revision was also aimed at identifying areas where knowledge is insufficient and to set priorities for further research.


Asunto(s)
Arachis , Fenoles , Antioxidantes/química , Arachis/química , Fenoles/análisis , Extractos Vegetales/química , Semillas/química
5.
J Ethnopharmacol ; 290: 115078, 2022 May 23.
Artículo en Inglés | MEDLINE | ID: mdl-35157954

RESUMEN

ETHNOPHARMACOLOGICAL RELEVANCE: Minthostachys verticillata (Griseb.) Epling (Lamiaceae) is a plant used in folk medicine for digestive or respiratory disorders. In addition, it is incorporated as condiment, in foods, as beverage flavoring or mate. The ethnopharmacological interest of M. verticillata resides in its essential oil (EO). Part of group has demonstrated the immunomodulatory ability of EO giving this oil a biological potential not known until that moment and conducted studies to evaluate their possible application in diseases of veterinary interest. However, the immunomodulatory effects of EO administered orally have not been fully characterized. AIM OF THE STUDY: This study evaluated the impact of EO oral administration on gastrointestinal and immune health through measurement of immunological and oxidative parameters in mice. MATERIAL AND METHODS: The EO was extracted from the leaves, slender stems and flowers of M. verticillata by hydrodistillation and chemical analyzed by gas chromatography-mass spectrometry (GC-MS). Prior to in vivo study, the cytotoxic effect of EO was determined using the human colon carcinoma Caco-2 cell line. For in vivo study, three groups of male Balb/c mice (n = 3) were orally administered with saline solution (control group) and EO (5 or 10 mg/kg/day) during 10 consecutive days. Subsequently, histological and hematological parameters, cytokines production, oxidative markers and CD4+ and CD8+ T cells were evaluated. RESULTS: The chemical analysis of EO revealed the presence of a high content of monoterpenes, being the main pulegone (76.12%) and menthone (14.28%). The EO oral administration improved mice growth performance and modulated systemic adaptive immune response by increasing in the total leukocyte number. A high percentage of CD4+ T cells were observed whereas the number of CD8+ T cells was not altered. EO did not alter the morpho-physiology of intestine and improved total antioxidant capacity by decreasing MDA concentrations. In addition, EO decreased the IL-6 levels and increased in the IL-4 and IL-10 concentrations. CONCLUSION: Results indicate that M. verticillata EO modulate inflammatory and oxidative parameters constituting a natural alternative which could be applied to improve gastrointestinal and immune functionality in animals.


Asunto(s)
Sistema Digestivo/efectos de los fármacos , Sistema Inmunológico/efectos de los fármacos , Lamiaceae , Aceites Volátiles/farmacología , Animales , Sangre/efectos de los fármacos , Linfocitos T CD4-Positivos/efectos de los fármacos , Linfocitos T CD8-positivos/efectos de los fármacos , Línea Celular Tumoral , Citocinas/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Humanos , Interleucina-10/metabolismo , Interleucina-4/metabolismo , Interleucina-6/metabolismo , Masculino , Medicina Tradicional , Ratones , Ratones Endogámicos BALB C , Monoterpenos/química , Monoterpenos/farmacología , Estrés Oxidativo/efectos de los fármacos
6.
Einstein (Säo Paulo) ; 20: eRC6903, 2022. graf
Artículo en Inglés | LILACS-Express | LILACS | ID: biblio-1394323

RESUMEN

ABSTRACT Prune belly syndrome is a rare congenital disease of unknown etiology that is present in one in every 40 thousand live births, and predominantly affects males, at a ratio of 4:1. In males, it presents with anomalies in the urinary system, absence of abdominal muscles, bilateral cryptorchidism, and infertility. In women, the syndrome has variable presentations, but fertility is preserved. Searching the medical literature, we found only one case of prune belly syndrome in pregnant women. Therefore, the patient in this report is the second case. She was primiparous, 25-years-old, with no abdominal muscles, severe congenital kyphoscoliosis, and pulmonary restriction. Elective cesarean section was performed at 37 weeks of gestation due to maternal risk of uterine rupture by transverse presentation and fetal risk of intrauterine growth restriction. The pre-anesthetic approach defined that general anesthesia might have more risks for the patient due to severe maternal lung disease compared to ultrasound-guided locoregional anesthesia. During prenatal care, there were some maternal complications, such as asthma exacerbations, abdominal pain, and constipation. The newborn was born small for gestational age and this can possibly be explained by maternal restrictive lung capacity. The newborn presented with Apgar score 8/9 and tachypnea, but improved after two hours of life.

7.
J Agric Food Chem ; 69(50): 15066-15075, 2021 Dec 22.
Artículo en Inglés | MEDLINE | ID: mdl-34878778

RESUMEN

The agro-industry produces numerous byproducts that are currently underused, and its waste contributes to environmental pollution. These byproducts represent an important and economical source of bioactive ingredients, which can promote the sustainable development of high-value-added functional foods. In this context, micro- and nanoencapsulation systems allow for the incorporation and stabilization of the bioactive agents in foods. This perspective will review recent advances in the use of agro-industrial byproducts as a source of bioactive agents. In addition, the latest advances in micro- and nanoencapsulation to improve the stability, solubility, and bioaccessibility of bioactive agents as functional food ingredients are exposed.


Asunto(s)
Ingredientes Alimentarios , Manipulación de Alimentos , Alimentos Funcionales
8.
Curr Res Food Sci ; 4: 132-140, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33778773

RESUMEN

The objective was to evaluate the technological processing (protection strategies and storage conditions) influence on viability, on probiotic properties and adsorbent aflatoxin B1 capacity of S. boulardii RC009. Also, the yeast biological safety was evaluated. Lyophilisation (DL) and encapsulation â€‹+ â€‹lyophilisation (EL) were conducted. Yeast protected with maltodextrin (M) or WPC stored at 4 â€‹°C reduced 1 and 2 log the viability, respectively. Yeast protected with M stored at 25 â€‹°C reduced 1 log after 70 â€‹d; with WPC the viability significantly reduced 3 log after 30 â€‹d. Technological processing improved the coaggregation's capacity with pathogens and DL process allowed the greatest AFB1 adsorption. S. boulardii 106 â€‹cells/mL were no toxic to Vero cells (p˂0.05). Saccharomyces boulardii RC009 protected with M or WPC maintained viability after technological processing. It possesses a great capacity for AFB1 adsorption and probiotic properties and could be considered a candidate with proven safety for functional food products development.

9.
Geburtshilfe Frauenheilkd ; 81(1): 46-60, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33487665

RESUMEN

In December 2019, a new viral respiratory infection known as coronavirus disease 2019 (COVID-19) was first diagnosed in the city of Wuhan, China. COVID-19 quickly spread across the world, leading the World Health Organization to declare it a pandemic on March 11, 2020. The disease is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a similar virus to those involved in other epidemics such as severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV). Epidemiological studies have shown that COVID-19 frequently affects young adults of reproductive age and that the elderly and patients with chronic disease have high mortality rates. Little is known about the impact of COVID-19 on pregnancy and breastfeeding. Most COVID-19 cases present with mild flu-like symptoms and only require treatment with symptomatic relief medications, whereas other cases with COVID-19 require treatment in an intensive care unit. There is currently no specific effective treatment for COVID-19. A large number of drugs are being used to fight infection by SARS-CoV-2. Experience with this therapeutic arsenal has been gained over the years in the treatment of other viral, autoimmune, parasitic, and bacterial diseases. Importantly, the search for an effective treatment for COVID-19 cannot expose pregnant women infected with SARS-CoV-2 to the potential teratogenic risks of these drugs. Therefore, it is necessary to determine and understand the safety of anti-COVID-19 therapies prior to conception and during pregnancy and breastfeeding.

10.
Food Chem ; 319: 126472, 2020 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-32163839

RESUMEN

Whey protein is one of the most relevant co-products manufactured by the dairy industry and it is a powerful environmental pollutant. Therefore, the enzymatic hydrolysis of whey protein concentrate (WPC 35) to produce antioxidant peptides is an innovative approach which can provide added value to whey. The WPC 35 hydrolysis with trypsin was carried out for 4.31 h at 41.1 °C with an enzyme/substrate ratio of 0.017. Under such hydrolysis conditions, the peptides produced have the highest radical scavenging activity and cytoprotector effect. The WPC hydrolysate and a permeate ≤3 kDa were characterized by SDS-page, RP-HPLC and MALDI-TOF-MS. Furthermore, O2•- and HO• scavenging activity and the cytoprotective effect against a stress agent in epithelial cells of the rat ileum (IEC-18) were determined. In this study, strong antioxidant and cytoprotective peptides were obtained from a low-cost dairy industry product, which could improve consumers' health when used as functional ingredients.


Asunto(s)
Péptidos/metabolismo , Tripsina/metabolismo , Proteína de Suero de Leche/metabolismo , Animales , Antioxidantes/metabolismo , Hidrólisis , Ratas , Suero Lácteo/química
11.
Anim Nutr ; 6(1): 31-38, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32211526

RESUMEN

The present study was conducted to investigate the ability of Saccharomyces cerevisiae RC016 (Sc)-based feed additive to reduce liver toxicity, residual aflatoxin B1 (AFB1) levels and influence intestinal structure in broiler chickens fed chronic aflatoxin B1-contaminated diets. A total of 100 one-day-old male commercial line (Ross) broiler chickens were divided into 4 treatments, with 5 pens per treatment and 5 broiler chickens per pen. Birds were randomly assigned to 4 treatments, which were namely treatment 1 (T1), control diet (CD); T2, CD + Sc at 1 g/kg; T3, CD + AFB1 at 100 µg/kg; T4, CD + Sc at 1 g/kg + AFB1 at 100 µg/kg. The liver histopathology of broiler chickens fed diets with AFB1 showed diffused microvacuolar fatty degeneration. The addition of Sc showed normal hepatocytes similar to the control. The small intestine villi from AFB1 group showed atrophy, hyperplasia of goblet cells, prominent inflammatory infiltrate and oedema. In contrast, the small intestine villi from birds that received the yeast plus AFB1 showed an absence of inflammatory infiltrate, and atrophy; moreover, a lower number of goblet cells compared to the groups with AFB1 was observed. The morphometric intestine studies showed that a significant decrease (P < 0.05) in the crypt depth values when Sc was applied to AFB1-contaminated diets. Although the intestinal villus height and apparent adsorption area did not show significant differences (P > 0.05), there was a tendency to improve these parameters. The residual levels of AFB1 in livers were significantly reduced (P < 0.05) in the presence of the yeast. The present work demonstrated that the addition of Sc alone or in combination with AFB1 in the broiler chicken diets had a beneficial effect in counteracting the toxic effects of AFB1 in livers besides improving the histomorphometric parameters and modulating the toxic effect of AFB1 in the intestine.

12.
Carbohydr Polym ; 224: 115158, 2019 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-31472856

RESUMEN

In this study, water-soluble chitosan (Ch) derivatives were synthesized by the Maillard reaction between Ch and lactose. The Ch derivatives were characterized by FT-IR, 1H-NMR and SLS to determine their structure, degree of deacetylation (DD), and molecular weight (Mw). The solubility at physiological pH, the in vitro antioxidant activity against hydroxyl radical, anion superoxide radical and ABTS cation radical, and the cytotoxicity against epithelial cells of the rat ileum (IEC-18) were also evaluated. The Maillard reaction, derivatives with lower Mw and DD and greater solubility than Ch were obtained. The biological properties of the derivatives were dependent on the concentration, Mw and DD, with antioxidant activity greater than or equal to that of Ch and non-cytotoxic in a wide range of concentrations. The results indicate that Ch derivatization with lactose produces new water-soluble polysaccharides, with antioxidant activity and non-cytotoxic, which can be used as biomaterials for food and pharmaceutical applications.


Asunto(s)
Fenómenos Químicos , Quitosano/química , Citotoxinas/química , Depuradores de Radicales Libres/química , Lactosa/química , Agua/química , Animales , Línea Celular , Supervivencia Celular/efectos de los fármacos , Citotoxinas/toxicidad , Depuradores de Radicales Libres/toxicidad , Ratas , Solubilidad
13.
J Nutr Biochem ; 62: 50-58, 2018 12.
Artículo en Inglés | MEDLINE | ID: mdl-30245183

RESUMEN

We used water-soluble Chitosan obtained by Maillard reaction with glucosamine to microencapsulate soy genistein (Ge) and preserve its biological activity for oral administration. Release of Ge was pH dependent with a super Case II mechanism at pH 1.2 and an anomalous transport with non-Fickian kinetics at pH 6.8. Microencapsulated Ge retained its antioxidant properties in vitro and its daily administration to mice attenuated clinical signs of acute colitis, limited inflammatory reaction and reduced oxidative stress and tissue injury as well. Remarkably, after feeding microencapsulated Ge the production of IL-10 in colonic tissue was restored to levels of untreated controls. According to statistical multivariate analysis, this cytokine was the parameter with the highest influence on the inflammatory/oxidative status. Microencapsulation of Ge with derivatized Chitosan becomes an interesting alternative to develop therapeutic approaches for oxidative inflammatory diseases; our findings suggest that the soy isoflavone could be incorporated into any functional food for application in intestinal inflammation.


Asunto(s)
Antioxidantes/administración & dosificación , Colitis/dietoterapia , Genisteína/administración & dosificación , Administración Oral , Animales , Antioxidantes/química , Antioxidantes/farmacología , Quitosano/química , Colitis/inducido químicamente , Colitis/metabolismo , Citocinas/metabolismo , Suplementos Dietéticos , Modelos Animales de Enfermedad , Composición de Medicamentos/métodos , Femenino , Genisteína/química , Genisteína/farmacología , Interleucina-10/metabolismo , Ratones Endogámicos C57BL , Estrés Oxidativo/efectos de los fármacos , Solubilidad , Glycine max/química
15.
Rev. eletrônica enferm ; 20: 1-11, 2018. graf
Artículo en Inglés, Portugués | BDENF - Enfermería, LILACS | ID: biblio-1118923

RESUMEN

Objetivou-se avaliar as potencialidades de um jogo de computador, Caixa de Pandora,como ferramenta de apoio ao aprendizado de estudantes de enfermagem sobre o tema da violência contra a mulher. Trata-se de uma pesquisa quantitativa, realizada com 62 estudantes do curso de enfermagem de uma Instituição de Ensino Superior. Foi aplicado um questionário para analisar a abordagem ao problema da violência e o impacto do game no processo ensino-aprendizado. Analisou-se as respostas sobre o impacto do jogo e sua aceitação através da estatística descritiva. Os resultados mostraram que o jogo motivou a reflexão e favoreceu a construção de novos conhecimentos e a aprendizagem do público alvo. Conclui-se que o jogo se apresentou como uma ferramenta potente para ser utilizada no processo de ensino e formação de estudantes de saúde, especificamente os da enfermagem, sobre o tema da violência.


It was aimed to assess the potentials of a computer game, Pandora ́s Box, as a support tool for nursing students ́ learning about the theme of the violence against women.This is a quantitative research, carried out with 62 students of the nursing course from a Higher Education Institution. A questionnaire was applied to analyze the approach to the violence problem and the impact of the game in the teaching-learning process. The answers were analyzed about the impact of the game and its acceptance through the descriptive statistics. The results showed that the game motivated the reflection and favored the building of new knowledge and the learning to the target public. It was concluded that the game was presented as a potent tool to be used in the teaching process and training of health students, specifically to those of the nursing, on the theme of violence.


Asunto(s)
Humanos , Masculino , Femenino , Adulto , Juegos de Video , Educación en Enfermería , Violencia contra la Mujer
16.
Int J Biol Macromol ; 102: 200-207, 2017 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-28396271

RESUMEN

New water-soluble chitosan derivatives (WSCh) were obtained by Maillard reaction (MR) between glucosamine (GA) with both low and medium molecular weight chitosans (Ch). The WSCh showed larger solubility than the respective Ch, while their deacetylation degree (DD) decreased by approximately 12%. Infrared spectroscopy experiments of WSCh confirmed the formation of imine bonds after MR with intensified pyranose structure, and sugar molecules as polymer branches. However, a 6-times reduction of the molecular weight of WSCh was measured, indicating the breakdown of the polysaccharide chain during the MR. The polysaccharides quenched singlet molecular oxygen (1O2), with rate quenching constants correlating with the DD value of the samples, suggesting the important role of amino groups (-NH2) in the deactivation of 1O2. Additionally, all polysaccharides presented antimicrobial activity against pathogenic bacteria, e.g. Staphylococcus aureus, Escherichia coli, Salmonella sp., Enterococcus faecalis and Listeria ivanovii, as tested by their minimum inhibitory concentration (MIC). This way we obtained new water-soluble polysaccharides, with similar functional properties to those presented by native Ch, enhancing its potential application as carrier material for bioactive compounds.


Asunto(s)
Antibacterianos/química , Antibacterianos/farmacología , Fenómenos Químicos , Quitosano/química , Oxígeno Singlete/química , Agua/química , Acetilación , Bacterias/efectos de los fármacos , Concentración de Iones de Hidrógeno , Peso Molecular , Solubilidad
17.
Artículo en Inglés | MEDLINE | ID: mdl-28277172

RESUMEN

Whey is the main byproduct of the cheese industry. While the composition is variable, it retains up to 55% of milk nutrients. The beneficial features of whey indicates a promising source of new potentially probiotic strains for the development of food additives destined for animal production. The aim of this study was to identify Kluyveromyces spp. isolated from whey, to study some probiotic properties and to select the best strain to be encapsulated using derivatised chitosan. Kluyveromyces marxianus strains (VM003, VM004 and VM005) were isolated from whey and identified by phenotypic and molecular techniques. These three yeast strains were able to survive under gastrointestinal conditions. Moreover, they exhibited weak auto-aggregation and co-aggregation with pathogenic bacteria (Salmonella sp., Serratia sp., Escherichia coli and Salmonella typhimurium). In general the K. marxianus strains had a strong antimicrobial activity against pathogenic bacteria. The potential probiotic K. marxianus VM004 strain was selected for derivatised-chitosan encapsulation. Material treated with native chitosan exhibited a strong antimicrobial activity of K. marxianus, showing a total growth inhibition at 10 min exposure. However, derivatised-chitosan encapsulation showed a reduced antimicrobial activity. This is the first study to show some probiotic properties of whey-native K. marxianus, in vitro. An encapsulation strategy was applied using derivatised chitosan.


Asunto(s)
Alimentación Animal , Aditivos Alimentarios/química , Kluyveromyces/química , Suero Lácteo/química , Animales , Aditivos Alimentarios/aislamiento & purificación , Kluyveromyces/aislamiento & purificación
18.
Photochem Photobiol ; 90(6): 1251-6, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25244633

RESUMEN

The known O2((1)∆g)-sensitizer system Chitosan bounded Rose Bengal (CH-RB), with Rose Bengal (RB) immobilized by irreversible covalent bonding to the polymer Chitosan (CH), soluble in aquous acidic medium, was employed in the photodegradation of three tri-hydroxy benzene water-contaminants (THBs). The system sensitizes the O2((1)∆g)-mediated photodegradation of THBs by a process kinetically favored, as compared to that employing free RB dissolved in the same solvent. Additionally the free xanthene dye, degradable by O2((1)∆g) through self-sensitization upon prolonged light-exposure, is considerably protected when bonded to CH-polymer. The polymeric sensitizer, totally insoluble in neutral medium, can be removed from the solution after the photodegradative cycle by precipitation through a simple pH change. This fact constitutes an interesting aspect in the context of photoremediation of confined polluted waters. In other words, the sensitizing system could be useful for avoiding to dissolve dyestuffs in the polluted waters, in order to act as conventional sunlight-absorbing dye-sensitizers. In parallel the interaction CH-O2((1)∆g) in acidic solution was evaluated. The polymer quenches the oxidative species with a rate constant 2.4 × 10(8) M(-1) s(-1) being the process mostly attributable to a physical interaction. This fact promotes the photoprotection of the bonded dye in the CH-RB polymer.


Asunto(s)
Quitosano/química , Procesos Fotoquímicos , Fármacos Fotosensibilizantes/química , Polímeros/química , Contaminantes Químicos del Agua/química , Hidroxilación , Oxidación-Reducción , Solubilidad
19.
J Dairy Sci ; 97(9): 5328-36, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24952775

RESUMEN

Microcapsules (MC) made with gum arabic (GA) as shell material without and with ß-carotene (ßc) as core material were prepared by the spray-drying technique. The effect of these MC on the photodegradation of riboflavin (Rf) in whole milk by fluorescent daylight lamp irradiation was evaluated at a storage temperature of 4°C. The additions of 1.37mg/mL of MC without ßc (MC-GA) and with 0.54µg/mL of ßc (MC-ßc-GA) decreased the apparent first-order rate constant of Rf photodegradation by approximately 26 and 30%, respectively. A systematic kinetic and mechanistic analysis of the results indicates that the global protective effect of the MC is mainly due to the combination of quenching of the electronically excited triplet state of Rf and scavenging of the photogenerated reactive oxygen species, such as singlet molecular oxygen, superoxide radical anion and hydroxyl radical. A minor contribution to the photoprotective effect can be also associated with the inner-filter effect exerted by the MC, which partially blocks the direct excitation of Rf. These results allow us to conclude that photodegradation of Rf in milk can be considerably reduced by the addition of small amounts of MC, avoiding large losses in the nutritional value of milk.


Asunto(s)
Goma Arábiga/química , Leche/química , Fotólisis , Riboflavina/química , Animales , Cápsulas/química , Manipulación de Alimentos , Concentración de Iones de Hidrógeno , Oxígeno/química , Especies Reactivas de Oxígeno/metabolismo , beta Caroteno/química
20.
J Photochem Photobiol B ; 135: 48-54, 2014 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-24796645

RESUMEN

Kinetic and mechanistic aspects of the photochemical and microbiological degradation of the herbicide Maleic Hydrazide (MH) have been studied. Riboflavin (Rf, vitamin B2) was employed as a main photosensitizer whereas Humic Acid (HA) was included as a second sensitizer in order to more closely simulate natural environmental conditions. MH quenches excited singlet and triplet states of Rf, with rate constants close to the diffusion limit. The herbicide and dissolved molecular oxygen competitively quench triplet excited Rf. As a consequence the reactive oxygen species (ROS), superoxide radical anion (O2(-·)), hydrogen peroxide (H2O2) and singlet molecular oxygen (O2((1)Δg)) are produced by electron- and energy-transfer processes, respectively, as demonstrated by auxiliary experiments employing selective auxiliary quenchers and the exclusive O2((1)Δg) generator Rose Bengal (RB). As a global result, the photodegradation of Rf is retarded, whereas MH is degraded by the generated ROS. The bacteria Pseudomonas aeruginosa (Ps) and Bacillus subtilis (Bs), recognized as contaminants surface-water and soil and microbial antagonists of phytopathogenic, were used in the microbiological experiments. Results of the individual incubation of both bacteria in in the presence of MH indicate a stimulation on the Ps growth, implying the biodegradation of the herbicide, whereas MH only exerted a bacteriostatic effect on Bs.


Asunto(s)
Bacillus subtilis/metabolismo , Herbicidas/química , Herbicidas/metabolismo , Hidrazida Maleica/química , Fotólisis , Pseudomonas aeruginosa/metabolismo , Biodegradación Ambiental , Electrones , Contaminantes Ambientales/química , Contaminantes Ambientales/aislamiento & purificación , Contaminantes Ambientales/metabolismo , Herbicidas/aislamiento & purificación , Sustancias Húmicas , Cinética , Fármacos Fotosensibilizantes/química , Especies Reactivas de Oxígeno/química , Riboflavina/química
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