• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 120
  • 56
  • 23
  • 16
  • 11
  • 7
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 3
  • Tagged with
  • 283
  • 225
  • 116
  • 110
  • 25
  • 20
  • 19
  • 15
  • 14
  • 14
  • 14
  • 14
  • 13
  • 12
  • 11
  • 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.
231

Stanovení vybraných parametrů rozdílných způsobů zakládání porostu cukrové řepy

CHADRABA, Václav January 2019 (has links)
The work is focused on operational comparison of two technologies of sugar beet growth. The comparison took place on two adjacent plots with almost the same properties. On the first plot the stand was based on Stip-Tillage technology. On the second plot was used minimalization technology, specifically loosening and subsequent preparation before sowing using a compactor. Several parameters of the soil preparation were evaluated on the plots. Subsequently, the vegetation was monitored during the growing season. The thesis is also supplemented by yield parameters and simplified economic evaluation.
232

Viabilidade e utilização em confeitaria de corantes naturais obtidos a partir da variedade de uva black magic, da beterraba e do mirtilo

Rosa, Juliano da 30 April 2018 (has links)
Submitted by JOSIANE SANTOS DE OLIVEIRA (josianeso) on 2018-11-09T12:26:31Z No. of bitstreams: 1 Juliano da Rosa_.pdf: 355603 bytes, checksum: cebe24b4b8390d0aacde8be31620f889 (MD5) / Made available in DSpace on 2018-11-09T12:26:31Z (GMT). No. of bitstreams: 1 Juliano da Rosa_.pdf: 355603 bytes, checksum: cebe24b4b8390d0aacde8be31620f889 (MD5) Previous issue date: 2018-04-30 / UNISINOS - Universidade do Vale do Rio dos Sinos / Os corantes são substâncias adicionadas aos alimentos e bebidas, com a finalidade de conferir ou intensificar a coloração do produto, tornando-o mais atrativo. Usualmente, são empregados corantes artificiais tanto pelo menor custo de produção, quanto maior estabilidade em relação aos naturais. A busca por padrões de vida mais saudáveis, faz com que as indústrias busquem novas alternativas para atender o mercado. Este trabalho buscará, avaliar a viabilidade de utilização em confeitaria de corantes naturais obtidos por liofilização da variedade de uva black magic, beterraba e mirtilo, em substituição à corantes artificiais. Para tanto, os produtos foram preparados, liofilizados e testados na confeitaria por meio de sua adição ao merengue Francês; teste do °Brix; análise de cor e teste sensorial. Para as amostras em triplicata do °Brix da beterraba, mirtilo e uva, obteve-se respectivamente valores de: 5,92, 8,52 e 15,17°Brix, assim a beterraba possui a menor quantidade de açúcares entre os produtos. Com relação a cor, todos os produtos apresentaram-se satisfatórios, com cor intensificadas proporcionalmente, a medida que, aumenta-se a contração do corante. O teste sensorial, a beterraba dado o seu acentuado gosto característico, torna-se inviável para aplicação na confeitaria. Assim, entre os corantes avaliados: uva black magic, beterraba e mirtilo, apenas os da uva e mirtilo tem características gerais satisfatórias a sua utilização na confeitaria, ressalta-se entretanto, que são necessários estudos complementares quanto a adequação das condições de processamento, armazenamento, determinação de concentrações máximas permitidas, sendo estes os pontos mais críticos da produção. / Dyes are substances added to foods and beverages, in order to confer or intensify the color of the product, making it more attractive. Usually, artificial dyes are used for both the lower cost of production and greater stability over the natural ones. The search for healthier living standards causes industries to seek new alternatives to serve the market. This work will seek to evaluate the viability of confectionery of natural dyes obtained by lyophilization of the variety of black magic grape, beet and blueberry, replacing the artificial dyes. For this, the products were prepared, lyophilized and tested in the confectionery by means of their addition to the French meringue; °Brix test; color analysis and sensory testing. For the triplicate samples of beet, blueberry and grape °Brix, values of 5,92, 8,52 and 15,17 °Brix respectively were obtained, thus the beet has the lowest amount of sugar among the products. With regard to color, all products were satisfactory, with color intensified proportionally, as the dye contraction increases. The sensorial test, the beet given its accentuated characteristic taste, becomes impractical for application in the confectionery. Thus, among the evaluated dyes: black magic grape, beet and blueberry, only those of grape and blueberry have general satisfactory characteristics to their use in the confectionery, it is emphasized however that additional studies are necessary regarding the adequacy of the conditions of processing, storage, determination of maximum permissible concentrations, these being the most critical points of production.
233

Extração, clarificação e estabilização de betalaínas provenientes de talos de beterraba vermelha (Beta vulgaris L.)

Santos, Cláudia Destro dos, Cassini, Aline Schilling January 2017 (has links)
Milhões de toneladas de resíduos são gerados pela agroindústria todos os anos, gerando problemas ambientais e econômicos; muitos destes resíduos, entretanto, são ricos em nutrientes e compostos funcionais, o que poderia tornálos subprodutos com valor agregado. A utilização de subprodutos possibilita enriquecimento dos alimentos processados, redução de descarte no meio ambiente e melhor aproveitamento dos recursos naturais. Os talos de beterraba são um exemplo de resíduo com potencial a ser explorado e, assim como os bulbos, são ricos em betalaína, composto responsável pela sua coloração vermelho-violeta. Esses pigmentos são aplicáveis na indústria alimentícia como corantes naturais, mas a sua estabilidade é um dos maiores desafios frente a sua utilização. Neste contexto, este trabalho tem como objetivo principal estudar a extração, a clarificação e a estabilização de betalaínas provenientes de talos de beterraba vermelha. Para tanto, foi inicialmente estudado a viabilidade da utilização dos talos de beterraba como fonte de betalaínas e, em sequência, a extração destes compostos via esmagamento. A utilização de diferentes processamentos com vistas à melhora da extração e o seu impacto na estabilidade das betalaínas presente no extrato foram investigados: o processamento por alta pressão (HPP do inglês High Pressure Processing) e o tratamento térmico com alta temperatura por curto tempo (HTST do inglês High Temperature Short Time). Por fim, foi realizado um estudo de clarificação do extrato por meio de processo de separação por membranas (PSM). A clarificação foi aplicada por microfiltração (MF) seguido por ultrafiltração (UF). Além disto, a MF também foi operada no modo diafiltração (DF). A redução da atividade da enzima peroxidase, as características físico-químicas, a cor e a taxa de degradação das betalaínas ao longo do armazenamento foram avaliados nos extratos antes e após a clarificação. Os resultados mostraram que os extratos obtidos via esmagamento possuíam em média 45% da quantidade de pigmentos presentes no extrato dos bulbos de beterraba. O processamento por HPP não foi considerado uma boa alternativa para melhorar a extração e também não contribuiu para o aumento na estabilidade dos pigmentos presentes nos extratos. O tratamento térmico HTST causou uma pequena degradação das betalaínas; porém, quando aplicado por 120 s a 85,7 °C nos extratos com alta concentração inicial, promoveu uma redução na taxa de degradação das betalaínas da amostra tratada de 1,2 para 0,4 mg de betanina/100 ml de extrato por dia após uma semana de armazenamento. No estudo de clarificação por PSM, os experimentos de MF e UF apresentaram reduções no fluxo do permeado ao longo do processo, além de elevada tendência ao fouling, em ambas as membranas. A aplicação da MF batelada seguida por UF ocasionou uma redução de 99,5% da atividade de peroxidase. Quando a MF foi operada em modo DF, a alimentação do processo foi modificada de duas bateladas de 2 L cada para uma batelada de 3 L, aproveitando melhor os pigmentos da alimentação. Além disto, a clarificação contribuiu para a estabilidade das betalaínas, uma vez que a taxa de degradação reduziu de 0,32 e 0,41 mg de betanina/100 ml de extrato por dia para 0,2 mg de betanina/100 ml de extrato por dia no 10° dia de armazenamento. Os processos de MF, em modo batelada e DF, seguidos por UF promoveram redução na turbidez e no teor de sólidos solúveis, além de extratos clarificados com cor mais intensa, luminosa e avermelhada. / Every year a huge amount of waste is generated by agricultural industry, becoming a serious environmental and economic problem; many of these wastes, however, contain nutrients and functional compounds, which could make them by-products with added value. The use of by-products allows the enrichment of processed foods and the reduction of discard in the environment, ensuring a better use of natural resources. The beet stalks are an example of waste with potential to be explored and, as the root, are rich in betalains, whose provide their red-violet color. These pigments are applicable in the food industry as natural dyes. The stability of these pigments, however, is one of the biggest challenges of using it. In this context, this work aims to study the extraction and clarification of betalains from red beet stalks. Initially it was studied the feasibility of using beet stalks like a betalain source and, after that, the extraction of these compounds through crushing was carried out. The utilization of different processing to improve the extraction and the impact on the betalain stability present in the extract were studied: the high pressure processing (HPP) and the thermal treatment high temperature short time (HTST). Lastly, a study of clarification of the extract using the membrane separation processes (PSM) was carried out. Clarification was first applied by microfiltration (MF) followed by ultrafiltration (UF). In addition, MF was also operated in diafiltration mode (DF). The peroxidase activity reduction, physico-chemical characteristics, color and degradation rate of betalains over the storage were evaluated in the extracts before and after the clarification. The results show that the stalks extract by crushing had about 45% of the pigments content in the extract from root of beet. HPP was not considered a suitable alternative to improve the extraction and did not contribute to the increase in the stability of the pigments present in the extracts. The thermal treatment HTST caused a small degradation of betalains. However, when it was applied for 120 s at 85.7 °C, in the extracts with high initial concentration, it promoted a reduction in the betalain degradation rate of the treated sample from 1.2 to 0.4 mg of betanin/100 ml of extract per day after one week of storage. In the PSM clarification study, the MF and UF experiments, showed permeated flux reduction, indicating high fouling tendency on both MF and UF membranes. The application of MF followed by UF caused a reduction of 99.5% in peroxidase activity. When MF was operated in DF mode, the process feed was modified from two batches of 2 L each to a 3 L batch, making better use of feed pigments. In addition, the clarification experiments contributed to the betalain stability, as the betalain degradation rate reduced from 0.32 and 41 mg of betanin/100 ml of extract per day to 0.2 mg of betanin/100 ml of extract per day on the 10th day of storage. The MF processes, batch and DF mode, followed by UF promoted a reduction in the turbidity and soluble solids content and the clarified extracts had color more intense, bright and reddish.
234

Emiss?es de NH3 e N2O de composto org?nico e outras fontes de nitrog?nio aplicadas em sistema de produ??o de beterraba e alface / Emissions of NH3 and N2O from organic compost and other sources of nitrogen applied in production system beet and lettuce

SANTOS, Silvio da Silva 30 April 2013 (has links)
Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-05-05T18:01:27Z No. of bitstreams: 1 2013 - Silvio da Silva Santos.pdf: 1585710 bytes, checksum: 55512544fcf22f1d09c9080258d4c607 (MD5) / Made available in DSpace on 2017-05-05T18:01:27Z (GMT). No. of bitstreams: 1 2013 - Silvio da Silva Santos.pdf: 1585710 bytes, checksum: 55512544fcf22f1d09c9080258d4c607 (MD5) Previous issue date: 2013-04-30 / CAPES / There is a growing demand for organic fertilizers in Brazil, mainly for growing vegetables. Composting is a technique that can be used as an alternative to increase the availability and quality of organic fertilizers. During the composting process, there is emission gases such as carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4), which contribute to the greenhouse effect in the planet, also of ammonia (NH3), which reduces the efficiency of the composting process. Emissions of N2O and NH3 to the atmosphere has been attributed in part to the decomposition of organic matter from crop residues that are used in soil management systems. Thus, Chapter I aimed to characterize mixtures of elephant grass (Pennisetum purpureum) with different materials in order to produce an organic fertilizer rich in nutrients and can be used in the cultivation of sugar beets. The treatments were: (i) elephant grass + cattle manure;(ii) elephant grass + gliricidia; and (iii) elephant grass + castor cake. The evaluations were performed for 120 days. In this study, the compound formulated with a mixture of elephant grass and gliricidia resulted in higher concentrations of N, which shows the high potential of the material to be used as organic fertilizer for crops with high nutritional requirements. The N losses by volatilization were not relevant in the composting process. In the Chapter II it was evaluated the emissions of N2O and NH3 in the compost and other organic N sources used in the production of beet and lettuce. The treatments consisted of: (i) organic compound, prepared from the mixture of elephant grass with gliricidia (Gliricidia sepium) + fertilization coverage with castor bean; (ii) green manure dwarf mucuna (Mucuna deeringiana) + fertilization coverage with castor bean; (iii) cattle manure + fertilizer topdressing with chicken manure tanned; (iv) urea in planting and coverage; and (v) the control treatment (without nitrogen). Considering these results, the N2O emissions from the soil ranged from 7.37 and 2699.62 ?g N2O-N-1. The volatilization losses of ammonia ranged from 9.5 to 30% of the N applied. The application of cattle manure + chicken manure management proved to be environmentally more suitable for growing vegetables, since it resulted in lowest flow of nitrous oxide from the soil and ammonia volatilization. Moreover, urea is the N source that causes most losses by volatilization of ammonia, with zero residual effect for the next crop, in this case for the production of lettuce. The highest emissions were observed after rainfall, regardless of treatment, highlighting the importance of presence of water in the environment for the emissions of N2O to occur. / ? crescente a demanda por adubos org?nicos no Brasil, principalmente para o cultivo de hortali?as. A compostagem ? uma t?cnica que pode ser utilizada como alternativa para aumentar a disponibilidade e a qualidade dos fertilizantes org?nicos. Durante o processo de compostagem, h? emiss?o de gases, como g?s carb?nico (CO2), ?xido nitroso (N2O) e metano (CH4), que contribuem para o efeito estufa no planeta, al?m de am?nia (NH3), que reduz a efici?ncia do processo de compostagem. As emiss?es de N2O e NH3 para atmosfera tem sido atribu?das, em parte, ? decomposi??o da mat?ria org?nica proveniente dos res?duos vegetais que s?o empregados nos sistemas de manejo do solo. Dessa maneira, o Cap?tulo I teve como objetivo caracterizar misturas de capim-elefante (Pennisetum purpureum) com diferentes mat?rias-primas, visando produzir um adubo org?nico rico em nutrientes e capaz de ser usado no cultivo de hortali?as. Os tratamentos foram os seguintes: (i) capim-elefante + esterco bovino curtido; (ii) capim-elefante + gliricidia (Gliricidia sepium); e (iii) capim-elefante + torta de mamona. As avalia??es foram realizadas durante 120 dias. Neste estudo, o composto formulado com a mistura de capim-elefante e gliricidia resultou em maior teor de N, o que mostra o elevado potencial do material para ser usado como adubo org?nico em culturas com elevada exig?ncia nutricional. As perdas de N por volatiliza??o de am?nia n?o foram relevantes at? 34 dias de compostagem. O Cap?tulo II teve como objetivo avaliar as emiss?es de N2O e NH3 em composto org?nico e outras fontes de N usadas na produ??o de hortali?as. Os tratamentos consistiram da aplica??o de: (i) composto org?nico, preparado da mistura de capim elefante com gliricidia (Gliricidia sepium) + fertiliza??o em cobertura com torta de mamona; (ii) aduba??o verde com mucuna an? (Mucuna deeringiana) + fertiliza??o em cobertura com torta de mamona; (iii) esterco bovino curtido + fertiliza??o em cobertura com esterco de ave curtido; (iv) ureia em plantio e cobertura; e (v) tratamento controle (sem aplica??o de N). Considerando os resultados obtidos neste estudo, as emiss?es de N2O do solo variaram de 7,37 e 2699,62 ?g N-N2O m2h-1. As perdas por volatiliza??o de am?nia variaram de 9,5 e 30% do N aplicado. A aplica??o de esterco bovino curtido + esterco de ave curtido mostra ser um manejo ambientalmente mais adequado para o cultivo de hortali?as, por resultar em menores fluxos de ?xido nitroso do solo e volatiliza??o de am?nia. Por outro lado, a ureia ? a fonte de N que provoca as maiores perdas de N por volatiliza??o de am?nia com efeito residual nulo para a cultura seguinte, neste caso para produ??o de alface. As maiores emiss?es foram observadas ap?s precipita??es, independente do tratamento, destacando a necessidade da presen?a de ?gua no ambiente para que ocorram as emiss?es de N2O.
235

Efekti osmotske dehidratacije na poboljšanje održivosti, nutritivna i antioksidativna svojstva korena i lista celera (Apium graveolens) / Effects of osmotic dehydration on improving sustainability, nutritive and antioxidative properties of celery leaves and root (Apium graveolens)

Nićetin Milica 29 September 2017 (has links)
<p>U ovom radu proučavana je osmotska dehidratacija korena i lista celera u dva različita osmotska rastvora: vodenom rastvoru saharoze i natrijum hlorida i melasi &scaron;ećerne repe. Ispitivan je uticaj temperature procesa (20&deg;C, 35&deg;C i 50&deg;C) i vremena imerzije (1, 3 i 5h) na gubitak vode, prira&scaron;taj suve materije, sadržaj suve materije, vrednosti aktivnosti vode, promenu antioksidativne aktivnosti, promenu boje i promenu mineralnog sastava (K, Mg, Ca, Fe) tokom osmotske dehidratacije korena i lista celera.<br />Dokazano je da se povećanjem temperature i produženjem vremena trajanja procesa pospe&scaron;uje prenos mase tj. migracija molekula vode iz tretiranog biljnog materijala u okolni rastvor, i prodiranje molekula rastvorene supstance iz osmotskog rastvora u tretirano biljno tkivo. Snižene aw vrednosti u svim ispitivanim uzorcima ukazuju na pozitivan uticaj osmotske dehidratacije na mikrobiolo&scaron;ku stabilnost tretiranog korena i lista celera, &scaron;to je potvrdila i mikrobiolo&scaron;ka analiza.<br />Nasuprot rastvoru saharoze i natrijum hlorida koji je uticao na opadanje ukupne antioksidativnosti osmotski dehidriranih uzoraka, melasa &scaron;ećerne repe, kao bogat izvor prirodnih antioksidanasa, doprinosi povećanju antioksidativnosti i pobolj&scaron;anju funkcionalnog kvaliteta dehidriranog produkta. Usled transfera bojenih materija (melanoidina) iz melase, dolazi do tamnjenja tretiranih uzoraka. Bojene materije iz melase, zbog svojih antioksidativnih svojstava takođe doprinose pobolj&scaron;anju antioksidativnosti krajnjeg produkta. Dobijeni rezultati su pokazali značajno pobolj&scaron;anje mineralnog sastava korena i lista celera, dehidriranih u melasi &scaron;ećerne repe, dok je kod uzoraka tretiranih u rastvoru saharoze i natrijumhlorida uočeno smanjenje sadržaja ispitivanih mineralnih materija.<br />Statističkom obradom rezultata, uočeno je da su optimalni procesni parametri u pogledu efikasnosti procesa, kao i mikrobiolo&scaron;kog, nutritivnog, senzornog i funkcionalnog kvaliteta osmotski dehidriranog korena i lista celera, vreme trajanja procesa od 5h, na temperaturi od 50<sup><span style="font-size:11px;">&deg;</span></sup><span style="font-size:11px;">C</span>, u melasi &scaron;ećerne repe kao osmotskom rastvoru.</p> / <p>In this thesis, the osmotic dehydration of celery leaves and root in two different osmotic solutions (sucrose and sodium chloride dissolved in water and sugar beet molasses), was investigated. The effect of process temperature (20&deg;C, 35&deg;C i 50&deg;C) and immersion time (1, 3 and 5h) on water loss, solid gain, dry matter content, value of water activity, change of antioxidant activity, change of color parameters and change of mineral composition (K, Mg, Ca, Fe) was investigated.<br />It was found that increasing of process temperature and immersion time enhance mass transfer, intesifying migration of water molecules from the treated plant material into the surrounding solution and penetration of dissolved substances molecules from the osmotic solution into the treated plant tissue. Reduced aw values in all examined samples indicate a positive effect of osmotic dehydration on the microbiological stability of the treated celery leaves and root, which was also confirmed by the microbiological analysis.<br />Contrary to the solution of sucrose and sodium chloride, which was contributed to the decrease in total antioxidantivity of osmotically dehydrated samples, sugar beet molasses, as a rich source of natural antioxidants, contributed to an increase in antioxidant activity and an improvement in the functional quality of the dehydrated products. Due to the transfer of colored substances (melanoidins) from the molasses, the color of treated samples was darker. The colored substances from molasses, due to their antioxidant properties, also contribute to the enhancement of the antioxidativity of the final product. The results showed a significant improvement of the mineral content of celery leaves and root dehydrated in sugar beet molasses, while the samples treated in sucrose and sodium chloride solution show reduction of the examined mineral matters.<br />Statistical analysis revealed that optimal process parameters in terms of process efficiency, as well as the microbiological, nutritive, sensory and functional quality of the osmotically dehydrated celery leaves and root were: the process time of 5 hours, at a temperature of 50&deg;C, in sugar beet molasses as an osmotic solution.</p>
236

The Effect Of Ploidy Level On Plant Regeneration In Sugar Beet (beta Vulgaris L.)

Parastouk, Yasemin 01 September 2006 (has links) (PDF)
ABSTRACT Three different genotypes of sugar beet (diploid, triploid and tetraploid) / 4 varieties from diploid and triploid genotypes Soraya (KWS8123) and Leila (diploid), Visa (H68121) and Kassandra (triploid) and 2 lines from tetraploid genotype &Ccedil / BM315 and EA2075 (tetraploid) were used for investigating the effects of ploidy level on plant regeneration. Within three sugar beet genotypes, with respect to the treatments, triploids or tetraploids were found to respond to treatments significantly different when compared with diploids. The responses of polyploids were superior over the responses of diploids. Moreover, varieties from same genotype responded differently to treatments. Two types of calli were obtained / one white and friable with regenerative capacity and the other green and compact with no regenerative capacity. Concentration of sucrose on callus development was observed to be important. High concentration of sucrose (30 g/L) was found to cause discoloration and irresponsiveness of formed calli at callus enlargement and subsequent shoot regeneration stages. Therefore, low concentration (10 g/L) is advised to be used at these stages / although this caused less callus induction. Although initially used for the prevention of tissue discoloration, L-ascorbic acid inclusion into the medium was found to be positively affecting the regeneration capacity. When used at 20 mg/100 mL concentration, the only two spontaneous shoots from the tetraploid EA2075 line were obtained. Subsequently, these shoots were successfully rooted and whole plants were obtained. The effect of silver nitrate, in combination with L-ascorbic acid, on the prevention of sugar beet tissue discoloration was investigated. Unfortunately, the symptoms of discoloration did not diminish. Moreover, callus formation was reduced and the subsequent shoot recovery could not be achieved. Since a total of 3456 explants were used during this study, and only 2 whole plants were regenerated, the efficiency of plant recovery was calculated as a rather low value of 0.058 %.
237

Potassium uptake efficiency mechanisms and root exudates of different crop species

Samal, Debasmita 25 January 2007 (has links)
No description available.
238

Optimization Of Regeneration And Agrobacterium Mediated Transformation Of Sugar Beet (beta Vulgaris L.)

Baloglu, Cengiz Mehmet 01 September 2005 (has links) (PDF)
In this study, optimization of a transformation and regeneration system via indirect and direct organogenesis in cotyledon, hypocotyl, petiole, leaf and shoot base tissues of sugar beet (Beta vulgaris L. cv. ELK 345 and 1195) was investigated. Two different germination, three different callus induction and shoot induction medium was used for indirect organogenesis of sugar beet cultivar ELK 345. Except cotyledon, other explants (hypocotyl, petiole and leaf) produced callus. However no shoot development was observed from callus of these explants. Shoot base tissue of sugar beet cultivar 1195 was employed for direct organogenesis. Shoot development was achieved via direct organogenesis using 0.1 mg/L IBA and 0.25 mg/L BA. Root development and high acclimatization rate were accomplished from shoot base tissue. Different concentrations of kanamycin and PPT were applied to leaf blade explants to find out optimum dose for selection of transformants. Kanamycin at 150 mg/L and PPT at 3 mg/L totally inhibited shoot development from leaf blades. Moreover, an Agrobacterium mediated transformation procedure for leaf explants of ELK 345 was also optimized by monitoring transient uidA expression 3rd days after transformation. Effects of different parameters (vacuum infiltration, bacterial growth medium, inoculation time with bacteria, Agrobacterium strains and L-cysteine application in co-cultivation medium) were investigated to improve transformation procedure. Vacuum infiltration and Agrobacterium strains were significantly improved transformation procedure. Percentage of GUS expressing areas on leaves increased three folds from the beginning of the study.
239

Extração, clarificação e estabilização de betalaínas provenientes de talos de beterraba vermelha (Beta vulgaris L.)

Santos, Cláudia Destro dos, Cassini, Aline Schilling January 2017 (has links)
Milhões de toneladas de resíduos são gerados pela agroindústria todos os anos, gerando problemas ambientais e econômicos; muitos destes resíduos, entretanto, são ricos em nutrientes e compostos funcionais, o que poderia tornálos subprodutos com valor agregado. A utilização de subprodutos possibilita enriquecimento dos alimentos processados, redução de descarte no meio ambiente e melhor aproveitamento dos recursos naturais. Os talos de beterraba são um exemplo de resíduo com potencial a ser explorado e, assim como os bulbos, são ricos em betalaína, composto responsável pela sua coloração vermelho-violeta. Esses pigmentos são aplicáveis na indústria alimentícia como corantes naturais, mas a sua estabilidade é um dos maiores desafios frente a sua utilização. Neste contexto, este trabalho tem como objetivo principal estudar a extração, a clarificação e a estabilização de betalaínas provenientes de talos de beterraba vermelha. Para tanto, foi inicialmente estudado a viabilidade da utilização dos talos de beterraba como fonte de betalaínas e, em sequência, a extração destes compostos via esmagamento. A utilização de diferentes processamentos com vistas à melhora da extração e o seu impacto na estabilidade das betalaínas presente no extrato foram investigados: o processamento por alta pressão (HPP do inglês High Pressure Processing) e o tratamento térmico com alta temperatura por curto tempo (HTST do inglês High Temperature Short Time). Por fim, foi realizado um estudo de clarificação do extrato por meio de processo de separação por membranas (PSM). A clarificação foi aplicada por microfiltração (MF) seguido por ultrafiltração (UF). Além disto, a MF também foi operada no modo diafiltração (DF). A redução da atividade da enzima peroxidase, as características físico-químicas, a cor e a taxa de degradação das betalaínas ao longo do armazenamento foram avaliados nos extratos antes e após a clarificação. Os resultados mostraram que os extratos obtidos via esmagamento possuíam em média 45% da quantidade de pigmentos presentes no extrato dos bulbos de beterraba. O processamento por HPP não foi considerado uma boa alternativa para melhorar a extração e também não contribuiu para o aumento na estabilidade dos pigmentos presentes nos extratos. O tratamento térmico HTST causou uma pequena degradação das betalaínas; porém, quando aplicado por 120 s a 85,7 °C nos extratos com alta concentração inicial, promoveu uma redução na taxa de degradação das betalaínas da amostra tratada de 1,2 para 0,4 mg de betanina/100 ml de extrato por dia após uma semana de armazenamento. No estudo de clarificação por PSM, os experimentos de MF e UF apresentaram reduções no fluxo do permeado ao longo do processo, além de elevada tendência ao fouling, em ambas as membranas. A aplicação da MF batelada seguida por UF ocasionou uma redução de 99,5% da atividade de peroxidase. Quando a MF foi operada em modo DF, a alimentação do processo foi modificada de duas bateladas de 2 L cada para uma batelada de 3 L, aproveitando melhor os pigmentos da alimentação. Além disto, a clarificação contribuiu para a estabilidade das betalaínas, uma vez que a taxa de degradação reduziu de 0,32 e 0,41 mg de betanina/100 ml de extrato por dia para 0,2 mg de betanina/100 ml de extrato por dia no 10° dia de armazenamento. Os processos de MF, em modo batelada e DF, seguidos por UF promoveram redução na turbidez e no teor de sólidos solúveis, além de extratos clarificados com cor mais intensa, luminosa e avermelhada. / Every year a huge amount of waste is generated by agricultural industry, becoming a serious environmental and economic problem; many of these wastes, however, contain nutrients and functional compounds, which could make them by-products with added value. The use of by-products allows the enrichment of processed foods and the reduction of discard in the environment, ensuring a better use of natural resources. The beet stalks are an example of waste with potential to be explored and, as the root, are rich in betalains, whose provide their red-violet color. These pigments are applicable in the food industry as natural dyes. The stability of these pigments, however, is one of the biggest challenges of using it. In this context, this work aims to study the extraction and clarification of betalains from red beet stalks. Initially it was studied the feasibility of using beet stalks like a betalain source and, after that, the extraction of these compounds through crushing was carried out. The utilization of different processing to improve the extraction and the impact on the betalain stability present in the extract were studied: the high pressure processing (HPP) and the thermal treatment high temperature short time (HTST). Lastly, a study of clarification of the extract using the membrane separation processes (PSM) was carried out. Clarification was first applied by microfiltration (MF) followed by ultrafiltration (UF). In addition, MF was also operated in diafiltration mode (DF). The peroxidase activity reduction, physico-chemical characteristics, color and degradation rate of betalains over the storage were evaluated in the extracts before and after the clarification. The results show that the stalks extract by crushing had about 45% of the pigments content in the extract from root of beet. HPP was not considered a suitable alternative to improve the extraction and did not contribute to the increase in the stability of the pigments present in the extracts. The thermal treatment HTST caused a small degradation of betalains. However, when it was applied for 120 s at 85.7 °C, in the extracts with high initial concentration, it promoted a reduction in the betalain degradation rate of the treated sample from 1.2 to 0.4 mg of betanin/100 ml of extract per day after one week of storage. In the PSM clarification study, the MF and UF experiments, showed permeated flux reduction, indicating high fouling tendency on both MF and UF membranes. The application of MF followed by UF caused a reduction of 99.5% in peroxidase activity. When MF was operated in DF mode, the process feed was modified from two batches of 2 L each to a 3 L batch, making better use of feed pigments. In addition, the clarification experiments contributed to the betalain stability, as the betalain degradation rate reduced from 0.32 and 41 mg of betanin/100 ml of extract per day to 0.2 mg of betanin/100 ml of extract per day on the 10th day of storage. The MF processes, batch and DF mode, followed by UF promoted a reduction in the turbidity and soluble solids content and the clarified extracts had color more intense, bright and reddish.
240

Porovnání senzorických vlastností džemů slazených steviol-glykosidy a dalšími sladidly

KÜFFNEROVÁ, Nela January 2018 (has links)
The aim of the diploma thesis was evaluation of sensoric attributes of blueberry and current jams sweetened by selected Steviol glycosides and their comparing with other sweeteners. For evaluation of sensoric attributes were used rebaudioside A, stevioside, aspartame, erythritol and sugar beet. Stevia rebaudiana var. Bertoni is a persistent plant, which contains sweetening Steviol glycosides, which have a use in food processing. They are available in the area of EU indicated as E960 since 2011. The most used Steviol glycosides are stevioside and rebaudioside A, which are demarcated with a high sweetness, which could be 200-400 times higher than saccharose. The usage of sweeteners is legislatively allowed, which means it is also allowed to do sensoric analyse and detect perception of added substances in food. These analyses evaluate food with the help of sense - perception. Methodical part of the work contains procedure, used methods for gaining evaluation of data from a sensoric analyse after the degustation of jams, which has taken place with the presence of ten judges - an academic students in the working compartment of University of South Bohemia. Respondents entered their evaluation into protocols, which were prepared in advance. The results of diploma thesis are evaluated by the method of Kramer, which is used for this kind of analyse. The critical scale between 20 and 40 with the value of probability P = 95% was defined according to this method. Evaluation is described with the help of graphs and tables, added with a wordily describtion. Conclusion of analyse of diploma thesis is, that the usage of Steviol glycosides is not most suitable way of sweetening jams. Acceptable valuations of jams containing Steviol glycosides were proven in parameters of colour and aroma. The reasons for less successful evaluation of Steviol glycosides could be due to bad pH of food or badly chosen dosing, without combination of other kinds of sweeteners. The best sensory characteristics traditionally showed sugar beet and aspartame followed by rebaudioside A and stevioside, which were placed on the third and forth place from five used sweeteners. The part of the diploma thesis was an evaluation of questionnaire, where the result was, that asked people preferred fruit ingredient of jams (type of fruit, amount) not their way of sweetening while choosing a jam.

Page generated in 0.0919 seconds