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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
371

Zhodnocení fyzikálních a chemických parametrů plodů dosud méně využívaných druhů drobného ovoce a návrh nového nealkoholického nápoje z tohoto ovoce / Evaluation of Physical and Chemical Parameters of Still Less Exploited Species of Small Fruit and Proposal of a New Soft Drink from this Fruit

Cetkovská, Jitka January 2016 (has links)
This thesis deals with still less expolited species of small fruit, evaluation of its physical and chemical parameters and proposal of a new soft drink from one of the studied species of furit. Firstly, for the characterisation of basic nutrition parameters (dry matter, content of organic acids and saccharides) and biologicaly active substances (vitamin C, anthocyanins and phenolic compounds) suitable titration, spectrophotometric, chromatographic and electrophoretic methods were chosen, optimized and validated. The sample preparation procedure was optimized as well. For three years (2010–2012) the content of listed parameters was monitored in some cultivars of five species of small fruit: in seven cultivars of sea buckthorn, in ten cultivars of cornelian cherry, in twelve cultivars of rowanberry, in two cultivars of chokeberry and in seventeen cultivars of elderberry. By means of Duncan’s test, analysis of principal components (PCA) and cluster analysis (CLU) the main differences between studied cultivars were observed mainly in sea buckthorn and rowanberry, where single cultivars were easily distinguishable from others on the basis of genetic origin. On the basis of comparison of determined parameters in studied species of fruit and with collaboration with fruit processing company the suitable species of fruit for commercial utilization was chosen – elderberry, as a important source of anthocyanins and phenolic compounds. A new soft drink as a proposal of utilization of this fruit was created – fruit juice or nectar with portion of elderberry juice. Mixed juices and nectars with various composition were prepared from elderberry and grape juice and the sensory analysis of these drinks was performed. The best evaluated were 100% fruit juices prepared with 30–50% portion of elderberry juice. The composition was jurally protected. On the basis of this protection the product consisted from 100% fruit juice with 10% of elderberry component mixed with apple and grape juice was introduced to the market by the fruit processing company.
372

Zkoumání účinku kreatinu v kombinaci s hořčíkem a vitamínem C na výkonost jedince / Investigation of the effect of creatine in combination with magnesium and vitamin C on the performance of the individual person

Vlasák, Jan January 2017 (has links)
Creatine is nitrogen-containing organic acid which naturally occurs in the human body. The aim of this work was to determine the optimal dose of creatine in combination with vitamin C and magnesium for male respondents aged 18-26 years. They were divided into two groups differing in the creatine dosage. Group 1 took smaller dose of creatine (3 g per day) and group 2 higher dose of creatine (10 g per day). Both groups took both magnesium and vitamin C at constant doses throughout the study. The effects of significantly different dose of creatine in the individual groups were compared with each other in terms of the performance of individuals in the powerlifting, the anthropological changes and the overal metabolism of the intakes. In all disciplines of powerlifting, group 1 recorded higher average weight gains, which were not found to be statistically significant at a significance level of alpha 0,05. Anthropological changes were measured using the InBody 160 and a diagnostic measuring tape. In both cases, group 1 recorded better results than group 2, but these results were not statistically significant at a significance level of alpha 0,05. The total metabolism of the accepted dietary supplements was investigated through analytical methods. The urine of each respondent was regularly collected and subsequently analyzed during the research. Determination of creatinine, a creatine waste product, was performed by UV-VIS spectrophotometry using the Jaffe reaction. Vitamin C was analyzed by RP-HPLC. Magnesium was determined by the ICP-OES method. After creatine suplemantion of 3 per day, group 1 showed a slight increase in creatinine in the urine, but still in the physiological range. At the significance level alpha 0,05 there was no statistically significant difference. Group 2 showed an increase above the physiological limit which was already a statistically significant difference. Overall, creatine supplementation of 3 g per day has been found as a sufficient intake of creatine needed to build up muscle mass, increase energy metabolism and overall physical performance. The metabolization itself works very well and within the physiological values.
373

Contribution to the development of electrochemical methods for liquid chromatographic analysis and drug quality monitoring

Sarakbi, Ahmad 26 November 2014 (has links)
The present thesis work is dedicated to the implementation of novel electrochemical methods for the assay of drug compounds such as paracetamol and ascorbic acid and biologically relevant biothiols such as cysteine and glutathione. Particular attention has been paid to the development and application of amperometric detectors allowing for a readily surface renewing and for highly selective and sensitive assays.<p>Coupling of a screen printed electrochemical detector with a monolithic chromatographic column was performed for high-throughput analysis along with selectivity, sensitivity and good precision. The modification of a glassy carbon electrode with a perm-selective membrane was investigated in order to provide an electrochemical sensor for on-site analysis. Acetaminophen was investigated as a model drug compound because of its extensive use in drug “pain killer” medication.<p>Along with the aims of this thesis, a silver polycrystalline electrode was investigated as a sensitive and class selective electrode for the assay of small thiol-based molecules. The silver electrode was implemented for the first time as an amperometric detector coupled to liquid chromatography for the assay of thiols. Application to the study of thiol species present in white wines was realized in order to illustrate the potential of the silver working electrode as amperometric detector. / Doctorat en Sciences biomédicales et pharmaceutiques / info:eu-repo/semantics/nonPublished
374

Le stress oxydatif d’origine nutritionnelle en période néonatale chez le cochon d’Inde et son impact à l’âge adulte sur l’homéostasie redox, le métabolisme énergétique et la méthylation génique

Teixeira Nascimento, Vitor 06 1900 (has links)
Problématique : Durant la période fœtale, le métabolisme global du fœtus fonctionne en hypoxie, ce qui limite la phosphorylation oxydative dans la mitochondrie, et par conséquent la production d’adénosine triphosphate (ATP). Ces conditions sont nécessaires pour le développement intra-utérin. Lors de la naissance, l’augmentation des concentrations d’oxygène et un stress oxydatif permettent une transition métabolique. Une charge oxydative supplémentaire en période néonatale pourrait perturber cette transition métabolique et causer des complications. La nutrition parentérale (NP) administrée aux nouveau-nés prématurés apporte un triple fardeau oxydatif : une exposition à des peroxydes oxydants autogénérés par l’interaction des composants de la NP, une carence en vitamine C (instable en solution), et une déficience en glutathion, vu la charge oxydative élevée. Cette charge oxydative excessive affecte l’homéostasie redox au foie et aux poumons, ainsi que le métabolisme énergétique hépatique, et ce, par des effets immédiats et à long-terme. La méthylation de l’ADN est un possible mécanisme qui explique les effets à long terme. Le but de ce travail était de caractériser l’impact à court- et long-terme de la NP néonatale sur l’homéostasie redox, la méthylation de l’ADN, et le métabolisme des glucides et lipides, en isolant chacun des facteurs nutritionnels. Méthodes : Des cochons d’Inde ont été divisés dans les groupes suivants 1) NP : nutrition intraveineuse complète ; 2) NP+ glutathion disulfure (GSSG) (6 ou 12µM- substrat pour la synthèse intra-cellulaire de glutathion); 3) Diète complète : nutrition orale complète 4) Diète déficiente en Vitamine C; 5) Diète déficiente en Cystéine; 6) Diète double déficiente; ou. À 1 semaine de vie, la moitié des animaux était sacrifié et l’autre moitié a commencé à manger une diète complète jusqu’à l’âge adulte. Résultats et discussion : Les animaux ayant reçu une NP néonatale ont un métabolisme énergétique permettant la synthèse de nicotinamide adénine dinucléotide phosphate (NADPH) par l’augmentation de l’activité de la glucokinase (captation de glucose), et diminution de celles de la phosphofructokinase-1 (PFK-1) (glycolyse) et acétyl-CoA-carboxylase-1 (ACC)(lipogenèse). À l’âge adulte, les animaux ont une diminution des niveaux de GSSG, indiquant un débalancement de l’homéostasie redox vers le côté réducteur programmé par la NP néonatale. L’activité augmentée de l’ACC suggère une tendance à accumuler les lipides au foie à la suite d’une diète riche en glucides. L’ajout de glutathion à la NP ne prévient pas ces perturbations, car les déficiences en glutathion et vitamine C jouent un rôle sur la modulation des niveaux protéiques de l’ACC. Les diètes néonatales déficientes en vitamine C et cystéine augmentent l’activité de la PFK-1. Cette augmentation se maintient jusqu’à l’âge adulte chez les mâles, mais pas chez les femelles. Les niveaux protéiques de la glucokinase et ACC sont diminués à 1 semaine, et ceux de l’ACC sont élevés à 3 mois dans les groupes ayant reçu une des diètes déficientes. Ces effets sont similaires à ceux trouvés dans les animaux nourris avec la NP, suggérant que la déficience de la NP en ces nutriments et non les peroxydes cause ces effets. Dans tous les groupes, un stress oxydatif a été démontré à 1 semaine de vie, soit par l’augmentation des niveaux de GSSG, ou la diminution du GSH. Cet effet est vrai pour le foie et le poumon. Une réponse de Nrf2 est observée aussi au foie, ce qui caractérise un niveau bas de stress oxydatif. La baisse de GSH pulmonaire chez les animaux déficients est secondaire à l’inhibition oxydative de la voie de transméthylation au foie. Une diminution des niveaux d’ARNm de glutathion réductase et glutarédoxine sont observées, ce qui favorise encore le stress oxydatif pulmonaire. À long terme, les effets sont les opposés, soit débalancement de l’homéostasie redox vers le côté réducteur au foie et poumon. La méthylation de l’ADN était diminuée au foie des animaux nouveau-nés recevant les diètes déficientes, mais aucun changement n’a été observé aux poumons. Cette diminution est en accord avec les hauts niveaux d’ARNm des gènes de la protéine régulatrice de la glucokinase, et AMPK. À long-terme, l’effet inverse est observé pour la méthylation de l’ADN Conclusion : La NP modifie le flot d’énergie au foie à 1 semaine visant favoriser le métabolisme redox en détriment du métabolisme énergétique. Cet effet semble créer une déficience énergétique fonctionnelle, qui se développe en une lipogenèse accrue en âge adulte. Cela peut représenter un exemple de la plasticité développementale. Bien qu’un stress oxydatif en âge néonatal ne soit pas létal, il affecte le métabolisme énergétique et redox à long-terme, probablement par la méthylation de l’ADN. Les résultats de ce travail démontrent que ces animaux adultes ont une capacité accrue d’entreposer de l’énergie, soit par une lipogenèse plus élevée, soit par une accumulation d’énergie redox (glutathion). Aucune maladie métabolique n’était observée chez les animaux, mais il est attendu à ce que ces animaux développent ces maladies plus facilement suite à l’exposition à des insultes (habitudes de vie malsaines, tabagisme, etc.). / Problematic: During the fetal period, the general metabolism works under hypoxia, limiting oxidative phosphorylation in mitochondria and adenine triphosphate (ATP) synthesis. These conditions are necessary for intrauterine development. After birth, the increasing oxygen concentrations and the associated oxidative stress induce a metabolic transition. An excessive oxidative load during the neonatal period could perturb this transition. Parenteral nutrition (PN) administered to premature newborns comes with a triple oxidative burden: contaminating peroxides generated in solution, vitamin C deficiency (unstable in solution), and glutathione deficiency (caused by the high oxidative load). This oxidative load affects redox homoeostasis in the liver and lungs, as well as energy metabolism in the liver. These effects are not only immediate, but they are also delayed. DNA methylation is a candidate mechanism explaining the long-term effects. The objective of this work was to characterize the short- and long-term impacts of neonatal PN over redox homoeostasis, DNA methylation and carbohydrate and lipid metabolism by isolating each of these factors. Methods: Six groups of three-day-old guinea pigs received for 4 days either: 1) Total PN; 2) PN+glutathione disulfide (GSSG) (6 or 12µM-anti-peroxide);3) Vitamin C deficient; 4) Cysteine deficient; 5) Double deficient; or 6) Complete diets. At 1 week of life, half of the animals were sacrificed, and the other half started eating nutritionally complete diets until adulthood. Results and discussion: NP animals had energy metabolism shifted favouring nicotinamide adenine dinucleotide phosphate (NADPH) synthesis, as evidenced by the increase in glucokinase activity (glucose trapping in hepatocytes) and decrease in phosphfuctokinase-1 (PFK-1) (glycolysis) and acetyl-CoA-carboxyalase-1 (ACC) (lipogenesis) activities. Adding GSSG to parenteral nutrition prevents these changes. During adulthood, ACC activity is increased, suggesting a tendency to accumulate lipids after a diet rich in carbohydrates. Adding GSSG to PN does not prevent these changes as they seem to be caused by the nutritional deficiencies in vitamin C and cysteine. Neonatal diets deficient in vitamin C and cysteine increase PFK-1 activity. This increase is maintained until adulthood in males but not in females. Protein levels of glucokinase and ACC are decreased at 1 week of life and ACC levels are increased at adulthood in deficient groups. These effects are like the ones observed in PN animals. In all groups, oxidative stress is demonstrated in 1-week-old animals, either by an increase in GSSG levels, or a decrease in GSH. This is true for the liver and lungs. An Nrf2 response is also observed in the liver, suggesting a low level of oxidative stress. The decrease in lung GSH is secondary to the oxidative inhibition of the transmethylation pathway in the liver. Decreased levels of glutathione reductase and glutaredoxin mRNA levels are observed in lungs, favouring pulmonary oxidative stress. At adulthood, an imbalance in redox homeostasis towards a reducing state is observed in lungs and liver. DNA methylation was decreased in the liver of deficient animals at 1-week, but no changes were observed in lungs. This decrease is in accordance with the decrease in mRNA levels of glucokinase regulatory protein and AMPK. At adulthood, the opposite effect was observed for DNA methylation. Conclusion: Parenteral nutrition alters the energy flow in the liver of 1-week-old animals, favouring redox metabolism over energy metabolism. This effect seems to create a phenotype of functional energy deficiency which translates into an increased lipogenesis at adult age. This may be an example of developmental plasticity. Although neonatal oxidative stress is not lethal, it affects energy and redox metabolism at adulthood, probably through DNA methylation. The presented results demonstrate these animals have an increased capacity of storing energy, either through increased lipogenesis, or by an increase in redox energy accumulation (glutathione). No metabolic disease was observed. Although it would be expected that these animals would develop these diseases more easily after exposure to insults, such as unhealthy lifestyle habits, smoking, and others.
375

Fitohemijski skrining i biološka aktivnost ekstrakata i tradicionalnih proizvoda od plodova divljih ruža (Rosa L.;Rosaceae) / Phytochemical screening and biological activity ofextracts and traditional preserves of rose hips (Rosa L., Rosaceae)

Nađpal Jelena 13 July 2017 (has links)
<p>&nbsp;&nbsp; Cilj ove doktorske disertacije predstavljalo je ispitivanje fitohemijskog sastava i biolo&scaron;ke aktivnosti vodenih i metanolnih ekstrakata svežih i suvih plodova, kao i voćne ka&scaron;e i džema pripremljenih po tradicionalnoj recepturi od plodova &scaron;est samoniklih vrsta <em>Rosa L.: R. canina, R. dumalis, R. dumetorum, R. tomentosa, R. arvensis, R. sempervirens. </em>Ispitivanje fitohemijskog sastava obuhvatalo je LC -MS/MS analizu 64 odabrana fenolna jedinjenja, hinske kiseline (organske kiseline) kao i tri triterpenoida. Takođe, izvr&scaron;eno je spektrofotometrijsko određivanje sadržaja ukupnih fenolnih i flavonoidnih jedinjenja, kao i vitamina C. Evaluacija biolo&scaron;ke aktivnosti obuhvatala je in vitro ispitivanja&nbsp; antioksidantne i antiinflamatorne aktivnosti, kao i ispitivanje uticaja ekstrakata odabranih vrsta Rosa na aktivnost enzima acetilholinesteraze i rast tumorskih i netumorskih ćelija.</p><p>&nbsp;&nbsp; Sumiranjem dobijenih rezultata može se zaključiti da sveži i suvi plodovi ispitivanih vrsta <em>Rosa</em>, kao i voćne ka&scaron;e i džemovi predstavljaju značajan izvor vitamina C i fenolnih jedinjenja, sa elagnom kiselinom kao najzastupljenijom fenolnom komponentom. Takođe u pojedinim ekstraktima vrsta<em> R. dumetorum</em> i<em> R. tomentosa</em> detektovana je visoka koncentracija ursolne kiseline, dok je hinska kiselina prisutna u značajnoj koncentraciji u svim ispitivanim ekstraktima.</p><p>&nbsp; &nbsp;Ekstrakti ispitivanih vrsta, izuzev vrste<em> Rosa arvensis</em>, pokazali su visok antioksidantni potencijal koji se ogleda u njihovoj sposobnosti neutralizacije nekoliko radikalskih vrsta, redukcionom potencijalu i sposobnosti inhibicije lipidne peroksidacije. Ispitivani ekstrakti ispoljili su umerenu antiinflamatornu aktivnost u pogledu inhibicije produkcije odabranih metabolita ciklooksigenaznog (12-HHT, TXB<sub>2</sub>, PGE<sub> 2</sub>) i 12-lipooksigenaznog (12-HETE) metaboličkog puta arahidonske kiseline,&nbsp; posebno prostaglandina E&nbsp; . Takođe, in vitro ispitivanjem uticaja ekstrakata odabranih vrsta Rosa na aktivnost acetilholinesteraze pokazana je umerena aktivnost. Vodeni ekstrakti i ekstrakti voćnih ka&scaron;a vrsta <em>R. canina, R. tomentosa i R. sempervirens</em> pokazali su umereni inhibitorni potencijal prema rastu HeLa ćelijske linije, dok su ekstrakti vrste <em>R. sempervirens </em>pokazali aktivnost i prema HT-29 ćelijama. Dobijeni rezultati ukazuju na značajni potencijal plodova i tradicionalnih proizvoda ispitivanih vrsta <em>Rosa</em> za upotrebu u proizvodnji nutraceutika i funkcionalne hrane.</p> / <p>&nbsp;&nbsp; The aim of presented doctoral thesis was investigation of phytochemical composition and biological activity of water and methanol extracts of fresh and air-&nbsp; dried rose hips, as well as pur&eacute;e and jam made according to traditional recipe of&nbsp; hips of six wild growing<em> Rosa L. species: R. canina, R. dumalis, R. dumetorum, R</em>.&nbsp; <em>tomentosa, R. arvensis, and R. sempervirens.</em> Examination of phytochemical composition included LC-MS/MS analysis of 64 selected phenolic compounds, quinic&nbsp; acid (organic acid) and three triterpenoids. Also, total phenolic and flavonoid contents, as well as vitamin C contents were determined spectrophotometrically. Biological activity evaluation of extracts of six <em>Rosa</em> species included in vitro investigation of antioxidant, anti- inflammatory, anti-acetylcholinesterase and cytotoxic activity.<br />&nbsp;&nbsp; According to obtained results, fresh and air-dried rose hips, as well as their preserves present valuable source of vitamin C and phenolic compounds, especially&nbsp; ellagic acid, which was the most abundant examined phenolic compound. Furthermore, high concentration of ursolic acid was detected in some<em> Rosa &nbsp;</em> <em>tomentosa and R.&nbsp; rumetorum</em> extracts, while notable concentration of quinic acid&nbsp; was present in all examined extracts.<br />&nbsp;&nbsp; Extracts of all examined species, apart from <em>Rosa arvensis</em>, showed considerable antioxidant activity in terms of radical scavenging ability, reduction potential and inhibition of lipid peroxidation. Moreover, extracts exhibited moderate anti- inflammatory activity by means of inhibition of the main arachidonic acid metabolites &nbsp; formed incyclooxygenase-1 (12-HHT, TXB<sub>2</sub>, PGE <sub>2</sub> ) and 12-lipoxygenase (12-HETE)&nbsp; pathway, especially prostaglandin E<sub>2</sub> . Also, investigation of anti- cetylcholinesterase&nbsp; activity revealed moderate activity of extracts of all examined species. In addition,&nbsp; predominantly water extracts of fresh andair-dried rose hips, as well as pur&eacute;e of<em> R</em>.&nbsp; <em>canina, R. tomentosa </em>and <em>R. sempervirens</em> showed inhibitory activity toward HeLa, while <em>R.sempervirens</em> extracts also inhibited HT-29 cell growth. Presented results indicate significant potential of examined rose hips and their preserves for use as nutraceuticals and functional food.</p>
376

Caracterização do pólen apícola e utilização de vitaminas anti-oxidantes como indicadoras do processo de desidratação / Bee pollen characterization and antioxidants vitamins as indicators of the efficiency of dryness process

Oliveira, Karla Cristina Lima da Silva 14 February 2006 (has links)
O pólen apícola é o resultado da aglutinação do pólen das flores efetuada pelas abelhas, mediante acréscimo de substâncias salivares e pequenas quantidades de néctar ou mel. Trata-se de um produto consumido devido a seus benefícios nutricionais e terapêuticos. Sua importância nutricional é reconhecida por ser uma fonte protéica de elevado valor biológico, apresentando ainda carboidratos, lipídeos e minerais em sua composição, além das vitaminas do complexo B, C, E, &#946;-caroteno (como pró-vitamina A) e D; características estas que variam de acordo com sua origem botânica. Este trabalho teve como objetivos: caracterizar o pólen apícola produzido em diferentes épocas de coleta; obter dados científicos nacionais sobre o valor vitamínico de pólen apícola, relacionando-o com sua origem botânica e avaliar o efeito de dois tipos de processos de secagem do pólen apícola nos teores das vitaminas antioxidantes (&#946;-caroteno, como pró-vitamina A, vitamina C e E), considerando-se que estas vitaminas podem ser degradadas durante o processamento. Foram analisados os teores de vitaminas em 10 lotes de pólen apícola fresco, sendo 5 coletados em abril e 5 em outubro de 2005. Os lotes frescos de pólen apícola foram desidratados por um método convencional (desidratação à 42° C) e por um método alternativo (desidratação a 30-35° C). Além disso, foi realizada a identificação dos tipos polínicos encontrados nas amostras frescas de pólen apícola e a associação com o teor de vitaminas encontradas. Os valores das vitaminas determinados nas amostras frescas de pólen apícola variaram entre 13,5 e 42,5 &#181;g/g para vitamina E; 56,3 e 198,9 (&#181;g/g) para &#946;-caroteno e entre 273,9 e 560,3 &#181;g/g para vitamina C. De acordo com os resultados concluiu-se que a origem botânica e a época de coleta influenciaram no teor das vitaminas encontradas, interferindo inclusive na classificação da amostra como fonte ou não de determinada vitamina. Além disso, foi observado que o processamento alternativo foi mais eficaz que o processamento convencional na manutenção dos teores de todas as vitaminas em estudo. / Bee-collected pollen (bee pollen) is highly consumed around the world due its nutritive and therapeutic value. It contains proteins, carbohydrates, lipids, minerals and vitamins of complex B, vitamin C, D, E and totals carotenoids. However there are few literature data correlating nutritional composition with botanical origin and thermal process. The aim of this study was to quantify vitamins C, E and beta-carotene (provitamin A) in fresh and processed samples of bee pollen, correlating them with botanical origin. In addition, to evaluate the effect of drying process in the vitamin content. Ten samples of fresh bee pollen were collected, five in April and five in October of 2005. Samples of fresh bee pollen were dried by conventional method (drying at 42° C) and by an alternative method (drying at 30-35° C). The fresh bee pollen and the processed ones were assayed regarding their vitamin contents (n=30). Vitamin C was quantified by potentiometric titration, vitamin E by HPLC-normal phase and beta-carotene by open column chromatography. The date from botanical characterization of the bee pollen were obtained and correlated to the vitamins content. Vitamin content in fresh samples varied between 13,5 and 42,5 &#181;g/g for vitamin E; 56,3 and 198,9 (&#181;g/g) for &#946;-carotene and 273,9 and 560,3 &#181;g/g for vitamin C. The alternative drying method was more efficient that conventional one in retaining the vitamins. It was also concluded that the botanical origin and collecting season influenced the vitamin contents. Being important factor to predict if bee pollen was source or not of each vitamin.
377

Efeitos da radiação gama na microbiota e no teor de vitamina C de agrião (Nasturtium officinale) orgânico minimamente processado: aceitação e intenção de compra do produto irradiado / Effects of gamma radiation on the microbiota and vitamin C content of minimally processed organic watercr ess (Nasturtium officinale): Acceptance and intention to purchase the irradiated product

Martins, Cecilia Geraldes 17 October 2008 (has links)
O aumento do consumo de vegetais frescos e a globalização do mercado de hortaliças e frutas frescas provocaram um aumento na preocupação com as enfermidades transmitidas por alimentos (ETA) associadas a esses produtos. No Brasil, a produção de hortaliças orgãnicas vem crescendo, aproximadamente 40% ao ano. Considerando o exposto, foram analisadas 108 amostras de agrião orgãnico minimamente processado e irradiado coletadas, aleatoriamente, em produtores da região de São Roque, São Paulo, no período de novembro de 2005 a março de 2007, para avaliar a ecologia microbiana e a concentração de vitamina C ao longo da cadeia produtiva. As amostras de agrião orgãnico coletadas no campo e as de minimamente processado apresentaram populações superiores a 3,0 log UFC/g para aeróbios mesófilos, aeróbios psicrotróficos, Pseudomonas spp, coliformes termotolerantes e E. coli. Salmonella spp, E. coli 0157:H7 e L. monocytogenes não foram detectadas ao longo da cadeia produtiva. Comparando o processo mínimo com a combinação processo mínimo e irradiação constata-se que a combinação é mais eficiente uma vez que o processo mínimo seguido de exposição à dose de 1 kGy foi suficiente para reduzir de maneira significativa os diversos grupos de mícrorganismos no agrião. As concentrações de ácido ascórbico, ácido dehidroáscorbico e de vitamina C variaram em todas as etapas de processamento do agrião orgãnico minimamente processado e irradiado. Ao longo da vida-de-prateleira de agrião orgãnico minimamente processado e irradiado, a população de L. monocytogenes foi reduzida em, aproximadamente, 4,5, 5,5 e 5,9 ciclos log de acordo com as doses de 1 kGy, 2 kGye 3 kGy, respectivamente. Comportamento similar pode ser constatado para a população de Salmonella spp,. Os resultados da análise sensorial mostraram que o conhecimento ou não do processo de irradiação pelo consumidor não prejudica a aceitação e a intenção de compra do produto irradiado. Portanto o processo de irradiação visando a melhoria da qualidade de agrião orgânico é factível desde que sejam seguidas as Boas Práticas Agrícolas, Boas Práticas de Produção e Boas Práticas do Processo de Irradiação. / With the increase in the consumption of fresh vegetables and the globalization of the market for fresh fruits and vegetables, the concern with foodborne diseases associated with these products has also increased. In Brazil, the production of organic vegetables has increased approximately 40% per year in the last decade. Considering the above, 108 samples of irradiated, minimally processed, organic watercress from producers in the region of Sao Roque, Sao Paulo, were collected through November 2005 to March 2007, to assess the microbial ecology and vitamin C content. Samples of organic watercress collected at the farm level and at the industry level showed populations higher than 3,0 UFC/g for aerobic mesophilic, psychrotrophic, Pseudomonas spp, fecal coliforms and E. coli. Salmonella, E. coli O157:H7 and L. monocytogenes were not detected along the production chain. Comparing the minimal process and the combination of minimal process and irradiation, the combination was more efficient since even the lower dose (1 kGy) was sufficient to reduce the population of the various groups of microorganisms. The ascorbic acid, dehidroascorbic acid and vitamin C content varied at all stages of minimal processing as well as with the exposed doses of irradiation (1, 2 and 3 kGy). The population of L. monocytogenes decreased approximately 4.5, 5.5, and 5.9 log cycles, depending on the exposed doses, throughout the shelf life of irradiated minimally processed organic watercress. Similar behavior was showed by the Salmonella population. Sensory evaluation results showed that previous knowledge or none by consumers does not interfere with the acceptance and intention of purchase of irradiated minimally processed organic watercress. Thus the process of irradiation to improve the microbiological quality of minimally processed organic watercress is feasible provided that Good Agricultural Practice, Good Practice Production and Good Irradiation Practice are followed.
378

Alaterações das características químicas e físico-químicas do suco de goiaba (Psidium guajava L.) durante o processamento / Changes in the chemical and physico-chemical characteristics of the guava juice (Psidium guajava L.) during processing.

Fernandes, Aline Gurgel January 2007 (has links)
FERNANDES, Aline Gurgel. Alaterações das características químicas e físico-químicas do suco de goiaba (Psidium guajava L.) durante o processamento. 2007. 84 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Tecnologia de Alimentos, Fortaleza-CE, 2007 / Submitted by Nádja Goes (nmoraissoares@gmail.com) on 2016-05-30T13:17:43Z No. of bitstreams: 1 2007_dis_sgfernandes.pdf: 420665 bytes, checksum: e9cdf981335863a474b85601f8c58da2 (MD5) / Approved for entry into archive by Nádja Goes (nmoraissoares@gmail.com) on 2016-05-30T13:17:56Z (GMT) No. of bitstreams: 1 2007_dis_sgfernandes.pdf: 420665 bytes, checksum: e9cdf981335863a474b85601f8c58da2 (MD5) / Made available in DSpace on 2016-05-30T13:17:56Z (GMT). No. of bitstreams: 1 2007_dis_sgfernandes.pdf: 420665 bytes, checksum: e9cdf981335863a474b85601f8c58da2 (MD5) Previous issue date: 2007 / Fruit juices are important vitamin sources, mineral salts, organic acids and fibers, and including in the diet of the population, they can help to keep people healthy. During the stages of juice processing, some modifications in the fruit compounds can happen, affecting its sensorial and nutritional properties. Researches on the effects of processing on the nutritional compound tropical juice are scarce. Usually, only vitamin C losses are evaluated. This study determined the possible chemical and physical-chemical changes during the stages of guava tropical juice processing (extration, formulation / homogenization and pausterization) and storage (30 days). Soluble solids, pH, acidity, reducing sugars, total sugars, water activity, colour, vitamin C, anthocyanins, carotenoids, phenolic compounds and pectinametilesterase activity were analysed. We saw that only pH, carotenoids and pectinametilesterase activity parameters showed significant variations during the stages of juice processing. At the end of the processing, vitamin C, phenolic compounds and total anthocyanins contents were high, and it was an increase of total carotenoid amount in the guava juice. For the guava juice stored during 30 days it was observed no significant difference between the times zero and thirty days, for the analysed parameters. We conclude that since the chemical and physicochemical characteristics were affected just a little by processing and stored during 30 days, the hot fill processing, the glass packings used and added conservant were good factors of product preservation in this study. / Os sucos de frutas são importantes fontes de vitaminas, sais minerais, ácidos orgânicos e fibras, e incluídos na dieta da população podem ajudar a manter a saúde. Durante as etapas de processamento de sucos, podem ocorrer modificações nos componentes dos frutos, afetando suas propriedades sensoriais e nutritivas. Estudos sobre os efeitos do processamento nos constituintes nutricionais dos sucos tropicais são escassos. Geralmente, são avaliadas somente as perdas de vitamina C. Este trabalho objetivou determinar as possíveis alterações químicas e físico-químicas em suco tropical de goiaba durante as etapas de processamento (extração, formulação / homogeneização e pasteurização) e armazenamento (30 dias). Foram efetuadas determinações de sólidos solúveis, pH, acidez, açúcares redutores, açúcares totais, atividade de água, cor, vitamina C, antocianinas, carotenóides, compostos fenólicos e atividade da pectinametilesterase. Ao final do estudo, constatou-se que somente os parâmetros de pH, carotenóides e atividade da pectinametilesterase apresentaram variações significativas, durante as etapas de processamento do suco. O suco de goiaba se manteve ao final do processamento com elevados teores de vitamina C, compostos fenólicos, antocianinas totais, além do aumento da quantidade de carotenóides totais. No suco de goiaba armazenado por 30 dias observou-se que os parâmetros analisados não apresentaram diferença significativa entre o tempo zero e o trinta dias. Concluindo que as características químicas e físico-químicas são pouco afetadas pelo processamento e armazenamento (30 dias), pode-se considerar, portanto o processo de enchimento à quente (hot fill), as embalagens de vidro utilizadas e os conservantes adicionados como sendo bons fatores de preservação para o produto em estudo.
379

Efeitos da radiação gama na microbiota e no teor de vitamina C de agrião (Nasturtium officinale) orgânico minimamente processado: aceitação e intenção de compra do produto irradiado / Effects of gamma radiation on the microbiota and vitamin C content of minimally processed organic watercr ess (Nasturtium officinale): Acceptance and intention to purchase the irradiated product

Cecilia Geraldes Martins 17 October 2008 (has links)
O aumento do consumo de vegetais frescos e a globalização do mercado de hortaliças e frutas frescas provocaram um aumento na preocupação com as enfermidades transmitidas por alimentos (ETA) associadas a esses produtos. No Brasil, a produção de hortaliças orgãnicas vem crescendo, aproximadamente 40% ao ano. Considerando o exposto, foram analisadas 108 amostras de agrião orgãnico minimamente processado e irradiado coletadas, aleatoriamente, em produtores da região de São Roque, São Paulo, no período de novembro de 2005 a março de 2007, para avaliar a ecologia microbiana e a concentração de vitamina C ao longo da cadeia produtiva. As amostras de agrião orgãnico coletadas no campo e as de minimamente processado apresentaram populações superiores a 3,0 log UFC/g para aeróbios mesófilos, aeróbios psicrotróficos, Pseudomonas spp, coliformes termotolerantes e E. coli. Salmonella spp, E. coli 0157:H7 e L. monocytogenes não foram detectadas ao longo da cadeia produtiva. Comparando o processo mínimo com a combinação processo mínimo e irradiação constata-se que a combinação é mais eficiente uma vez que o processo mínimo seguido de exposição à dose de 1 kGy foi suficiente para reduzir de maneira significativa os diversos grupos de mícrorganismos no agrião. As concentrações de ácido ascórbico, ácido dehidroáscorbico e de vitamina C variaram em todas as etapas de processamento do agrião orgãnico minimamente processado e irradiado. Ao longo da vida-de-prateleira de agrião orgãnico minimamente processado e irradiado, a população de L. monocytogenes foi reduzida em, aproximadamente, 4,5, 5,5 e 5,9 ciclos log de acordo com as doses de 1 kGy, 2 kGye 3 kGy, respectivamente. Comportamento similar pode ser constatado para a população de Salmonella spp,. Os resultados da análise sensorial mostraram que o conhecimento ou não do processo de irradiação pelo consumidor não prejudica a aceitação e a intenção de compra do produto irradiado. Portanto o processo de irradiação visando a melhoria da qualidade de agrião orgânico é factível desde que sejam seguidas as Boas Práticas Agrícolas, Boas Práticas de Produção e Boas Práticas do Processo de Irradiação. / With the increase in the consumption of fresh vegetables and the globalization of the market for fresh fruits and vegetables, the concern with foodborne diseases associated with these products has also increased. In Brazil, the production of organic vegetables has increased approximately 40% per year in the last decade. Considering the above, 108 samples of irradiated, minimally processed, organic watercress from producers in the region of Sao Roque, Sao Paulo, were collected through November 2005 to March 2007, to assess the microbial ecology and vitamin C content. Samples of organic watercress collected at the farm level and at the industry level showed populations higher than 3,0 UFC/g for aerobic mesophilic, psychrotrophic, Pseudomonas spp, fecal coliforms and E. coli. Salmonella, E. coli O157:H7 and L. monocytogenes were not detected along the production chain. Comparing the minimal process and the combination of minimal process and irradiation, the combination was more efficient since even the lower dose (1 kGy) was sufficient to reduce the population of the various groups of microorganisms. The ascorbic acid, dehidroascorbic acid and vitamin C content varied at all stages of minimal processing as well as with the exposed doses of irradiation (1, 2 and 3 kGy). The population of L. monocytogenes decreased approximately 4.5, 5.5, and 5.9 log cycles, depending on the exposed doses, throughout the shelf life of irradiated minimally processed organic watercress. Similar behavior was showed by the Salmonella population. Sensory evaluation results showed that previous knowledge or none by consumers does not interfere with the acceptance and intention of purchase of irradiated minimally processed organic watercress. Thus the process of irradiation to improve the microbiological quality of minimally processed organic watercress is feasible provided that Good Agricultural Practice, Good Practice Production and Good Irradiation Practice are followed.
380

Changes in the chemical and physico-chemical characteristics of the guava juice (Psidium guajava L.) during processing. / AlateraÃÃes das caracterÃsticas quÃmicas e fÃsico-quÃmicas do suco de goiaba (Psidium guajava L.) durante o processamento

Aline Gurgel Fernandes 27 February 2007 (has links)
FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Os sucos de frutas sÃo importantes fontes de vitaminas, sais minerais, Ãcidos orgÃnicos e fibras, e incluÃdos na dieta da populaÃÃo podem ajudar a manter a saÃde. Durante as etapas de processamento de sucos, podem ocorrer modificaÃÃes nos componentes dos frutos, afetando suas propriedades sensoriais e nutritivas. Estudos sobre os efeitos do processamento nos constituintes nutricionais dos sucos tropicais sÃo escassos. Geralmente, sÃo avaliadas somente as perdas de vitamina C. Este trabalho objetivou determinar as possÃveis alteraÃÃes quÃmicas e fÃsico-quÃmicas em suco tropical de goiaba durante as etapas de processamento (extraÃÃo, formulaÃÃo / homogeneizaÃÃo e pasteurizaÃÃo) e armazenamento (30 dias). Foram efetuadas determinaÃÃes de sÃlidos solÃveis, pH, acidez, aÃÃcares redutores, aÃÃcares totais, atividade de Ãgua, cor, vitamina C, antocianinas, carotenÃides, compostos fenÃlicos e atividade da pectinametilesterase. Ao final do estudo, constatou-se que somente os parÃmetros de pH, carotenÃides e atividade da pectinametilesterase apresentaram variaÃÃes significativas, durante as etapas de processamento do suco. O suco de goiaba se manteve ao final do processamento com elevados teores de vitamina C, compostos fenÃlicos, antocianinas totais, alÃm do aumento da quantidade de carotenÃides totais. No suco de goiaba armazenado por 30 dias observou-se que os parÃmetros analisados nÃo apresentaram diferenÃa significativa entre o tempo zero e o trinta dias. Concluindo que as caracterÃsticas quÃmicas e fÃsico-quÃmicas sÃo pouco afetadas pelo processamento e armazenamento (30 dias), pode-se considerar, portanto o processo de enchimento à quente (hot fill), as embalagens de vidro utilizadas e os conservantes adicionados como sendo bons fatores de preservaÃÃo para o produto em estudo. / Fruit juices are important vitamin sources, mineral salts, organic acids and fibers, and including in the diet of the population, they can help to keep people healthy. During the stages of juice processing, some modifications in the fruit compounds can happen, affecting its sensorial and nutritional properties. Researches on the effects of processing on the nutritional compound tropical juice are scarce. Usually, only vitamin C losses are evaluated. This study determined the possible chemical and physical-chemical changes during the stages of guava tropical juice processing (extration, formulation / homogenization and pausterization) and storage (30 days). Soluble solids, pH, acidity, reducing sugars, total sugars, water activity, colour, vitamin C, anthocyanins, carotenoids, phenolic compounds and pectinametilesterase activity were analysed. We saw that only pH, carotenoids and pectinametilesterase activity parameters showed significant variations during the stages of juice processing. At the end of the processing, vitamin C, phenolic compounds and total anthocyanins contents were high, and it was an increase of total carotenoid amount in the guava juice. For the guava juice stored during 30 days it was observed no significant difference between the times zero and thirty days, for the analysed parameters. We conclude that since the chemical and physicochemical characteristics were affected just a little by processing and stored during 30 days, the hot fill processing, the glass packings used and added conservant were good factors of product preservation in this study.

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