Spelling suggestions: "subject:"dioscorea"" "subject:"oioscorea""
1 |
Analyse de la croissance et morphogenèse de l'igname Dioscorea complexe D. cayenensis-D. rotundataTrouslot, Marie Francine. January 1985 (has links)
Thesis (doctoral)--Université de Clermont-Ferrand II, 1983. / Errata slip inserted. Includes bibliographical references (p. 241-263).
|
2 |
Analyse de la croissance et morphogenèse de l'igname Dioscorea complexe D. cayenensis-D. rotundataTrouslot, Marie Francine. January 1985 (has links)
Thesis (doctoral)--Université de Clermont-Ferrand II, 1983. / Errata slip inserted. Includes bibliographical references (p. 241-263).
|
3 |
Studies on the hypolipidemic and antioxidative effects of different species of Dioscorea in hyperlipidemia hamstersWang, Chiung-yean 03 August 2005 (has links)
Recent studies indicated that Atherosclerosis was thought to the resulted from high blood lipid and oxidative stress. Dioscorea has been recognized as an edible medicinal herb as well as healthy plant. Related studies showed that Taiwannative yam (Dioscorea) exhibited hypoglycemic, antioxidative and hypolipidemic functions. However, researches regarding the best species of native Dioscorea revealing the efficacy with both antioxidative and hypolipidemic functions are limited. Previously our laboratory, found that three in five native species of Dioscorea provided by the Agricultural Research Institute had antioxidative effects. The goal of this study was to investigate the effects of this three Dioscorea species (TA01¡BTA03¡BTA05) on lipid metabolism and antioxidative ability of hamsters.
Hyperlipidemia hamsters induced by feeding high fat and high cholesterol diet for 3 weeks, were randomly divided into five groups. Group 1 was the control group fed with a high fat and high cholesterol diet (HF, 0.2% cholesterol and 12% fat) ; group 2 was the positive control group fed with a HF diet supplemented with 0.08% atorvastatin (HF+ATS) ; group 3 was TA01 group fed with a HF diet supplemented with 10% TA01 yam powder (HF+TA01) ; group 4 was TA03 group fed with a HF diet supplemented with 10% TA03 yam powder (HF+TA03) ; group 5 was TA05 group fed with a HF diet supplemented with 10% TA05 yam powder (HF+TA05). The experiment was conducted for 12 weeks. Blood was collcted to determine serum total cholesterol (TC) and triglycerol (TG) at week 4 and 8. The hamsters were scarified and the blood, liver and epididymal fat pads were collected at week 12. The weight of body, liver, epididymal fat pads ; Serum TC, TG, high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C) and oxidation of LDL (thiobarbituric acid reactive substances, TBARS) were determined ; TC, TG, TBARS, superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx) and glutathione reductase (GR) of liver were also analyzed.
Results indicated that TA01 group had significantly decreased serum TG (P < 0.05) at 4 and 8 weeks. Serum TC and TG of TA03 group were significantly lower than those of the control group at 8 weeks. No significant difference for TC and TG was found between TA05 and the control groups. After 12 weeks of Dioscorea feeding, liver weight and liver to body weight ratio of TA01 and TA03 groups compared to that of control group were significantly reduced. Epididymal fat pads weight and that the body weight ratio tended to be less compared to that of the control group. Serum TG concentration of TA01 was significantly decreased to 89% of the control group. Serum TC, TG and LDL-C concentrations of TA03 group were significantly decreased to 82, 89 and 83% of the control group, respectively. Serum HDL-C of TA03 group was unaffected and LDL TBARS tended to be decreased (1.67 ¡Ó 0.79 vs. 1.06 ¡Ó 0.57) compared to that of the control group. Liver TC concentrations of TA01 and TA03 groups both were significantly decreased to 88% of the control group. Liver TG and TBARS of TA01 and TA03 groups were unchanged. Catalase activities of TA01 and TA03 groups and GR activity of TA01 group were significantly higher than those of the control group. No significant differences were found in GPx and SOD activities among all groups.
In conclusion, TA01 and TA03 species of Taiwannative yam (Dioscorea) tubers exhibit beneficial effects on lipid profile and antioxidative status for hyperlipidemia induced by a high fat and high cholesterol diet. Among there species, TA03 reveals the best potential with both hypolipidemic and antioxidant effects, and was suggested to be used in the development of functional food for the modification of lipid profile and oxidative status in cardiovascular disease prevention .
|
4 |
A taxonomic student on Dioscorea L. (Dioscoreacea) of Taiwan.Liao, Chun-Kuei 12 June 2000 (has links)
Abstract
This thesis is to study habit, tuber, stem, leaf, flower and fruit morphology, phytogeography, and phenology in Dioscorea. Finally, concerns are given to the infrgeneric taxonomy.
Plants of Dioscorea in Taiwan are scandent vine; underground tuber or rhizome cylindrical, pyriform or spherical; steme terete or quadrangular in cross-section, ridged, or winged, green or violet, pubscent or glabrous or prickly; aerial tuber axilly or absent. Leaves alternate or opposite, simple or palmately- compound; simple leaves cordate or ovate-triangular, 3-9 nerved; leaflets of palmately-compound leaves lanceolate or ovate, nerves pinnately; 3-9 nerved; veinlets reticulate; petioles twisted and dilated at base. Flowers usually dioecious, arranged in axillay panicles, racemes, or spikes; male flowers solitary or fasciled on rachis, perianths 6, 2-whorled, tepals mostly similar, stamens 6, sometimes the inner 3 sterile, filaments attached to base of perianths, anthers 2 celled, longitudinally dehiscent, pistillodium rudimentary, present or absent; pistillate flowers solitary on rachis, perianths similar to the staminate, with 0, 3 or 6 staminodia; ovary inferior, trigonous, 3-celled, ovules 2 in each cell; stigmas 3, 2-lobed at apex. Fruit capsulate, tripterous. Seed 2 in each cell, with membranous wing. Flowering period is from April to September. Mostly fruiting from July to November. Most species of the genus in Taiwan are widely spreading in the island. Among the species in Taiwan, two endemic.
|
5 |
Variabilidade de isolados de Curvularia eragrostidis (Henn) meyer causando queima das folhas do inhame (Discorea cayennensis Lam.) no estado de PernambucoPAULA, Helenilza de 20 December 2000 (has links)
Submitted by (lucia.rodrigues@ufrpe.br) on 2017-03-13T12:23:23Z
No. of bitstreams: 1
Helenilza de Paula.pdf: 563470 bytes, checksum: 8516fe943f64533b1a028f0edced6282 (MD5) / Made available in DSpace on 2017-03-13T12:23:23Z (GMT). No. of bitstreams: 1
Helenilza de Paula.pdf: 563470 bytes, checksum: 8516fe943f64533b1a028f0edced6282 (MD5)
Previous issue date: 2000-12-20 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Leaf blight, caused by Curvularia eragrostidis, is one of the main diseases of the yam in Brazilian Northeast, however studies on the pathogen variability are inexistent. In order to characterize the variability of C. eragrostidis, 42 strains obtained from yam fields in the Pernambuco State were evaluated in relation to epidemiological components, physiologic characteristics and sensibility to iprodione. In the epidemiological components study, yam plants, cv. Da Costa, were inoculated with strains of C. eragrostidis (1x104 conidia/ml) and evaluated daily for occurrence and severity of disease symptoms, to record incubation period (IP) and area under disease progress curve (AUDPC). Strains were evaluated “in vitro” for micelial growth rate (MGR), sporulation (SP) and germination of conidia (GER), as well as for sensitivity to iprodione, evaluated by the lethal dose which inhibited 50% of micelial growth (DL50) and percentage of inhibition of conidium germination (ICG). There were significant differences (P=0.05) among the strains of C. eragrostidis in relation to all variables, resulting in different similarity groups of strains according to the Scott-Knott test. There were no significant correlation (P=0.05) between the variables associated with disease (IP and AUDPC) and the other variables studied (MGR, SP, GER, DL50 and ICG). When all variables were analyzed by the Euclidean distance (single linkage), the 42 strains were gathered into seven similarity groups. Therefore, there is variability among the strains of C. eragrostidis, which causes leaf blight of yam in different planting areas in Pernambuc / A queima das folhas, causada por Curvularia eragrostidis, constitui uma importante doença do inhame no Nordeste brasileiro, embora inexistam estudos sobre a variabilidade do patógeno. Com o objetivo de analisar a variabilidade de C. eragrostidis, 42 isolados obtidos de áreas de plantio de inhame do Estado de Pernambuco foram avaliados em relação a componentes epidemiológicos, características fisiológicas e sensibilidade ao fungicida iprodione. No estudo dos componentes epidemiológicos, plantas de inhame (cv. Da Costa) com quatro meses de idade foram inoculadas com os isolados de C. eragrostidis (1x104 conídios/ml) e avaliadas diariamente quanto à presença e severidade dos sintomas de queima, sendo obtidos o período de incubação (PI) e a área abaixo da curva de progresso de doença (AACPD). Cada isolado foi também avaliado “in vitro” quanto a características fisiológicas como taxa de crescimento micelial (TCM), esporulação (ESP) e germinação de conídios (GER), assim como em relação à sensibilidade ao fungicida iprodione, avaliada pela dose do fungicida suficiente para inibir 50% do crescimento micelial (DL50) e pela porcentagem de inibição da germinação dos conídios (IGC). Foram constatadas diferenças significativas (P=0,05) entre os isolados de C. eragrostidis em relação a todas as variáveis avaliadas, sendo possível a separação dos isolados em diferentes grupos de similaridade pelo teste de Scott-Knott. Não foram constatadas correlações significativas (P=0,05) das variáveis associadas à doença (PI e AACPD) com as demais variáveis (TCM, ESP, GER, DL50 e IGC). Utilizando o conjunto das variáveis, a análise da distância Euclidiana por ligações simples permitiu a separação dos 42 isolados de C. eragrostidis em sete grupos de similaridade. Os resultados obtidos indicam a existência de variabilidade entre os isolados do patógeno causando queima das folhas em diferentes áreas de cultivo de inhame de Pernambuco.
|
6 |
Phylogeny and taxonomic reexamination of the genus Dioscorea (Dioscoreaceae) / ヤマノイモ属(ヤマノイモ科)の系統と分類学的再検討Noda, Hiroshi 25 May 2020 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第22631号 / 理博第4620号 / 新制||理||1664(附属図書館) / 京都大学大学院理学研究科生物科学専攻 / (主査)教授 田村 実, 教授 工藤 洋, 教授 永益 英敏 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM
|
7 |
Características morfológicas e a emergência de sementes de duas etnovariedades de cará (Dioscorea trifida L.F)Andrade, Edfran Nascimento 26 June 2014 (has links)
Made available in DSpace on 2015-04-11T13:55:59Z (GMT). No. of bitstreams: 1
Edfran N Andrade.pdf: 1316078 bytes, checksum: d702483f274a562c755b8cc3e56f3cff (MD5)
Previous issue date: 2014-06-26 / Item withdrawn by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-07-21T20:06:37Z
Item was in collections:
Mestrado em Agronomia Tropical (ID: 17)
No. of bitstreams: 1
Edfran N Andrade.pdf: 1316078 bytes, checksum: d702483f274a562c755b8cc3e56f3cff (MD5) / Item reinstated by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-07-21T20:08:21Z
Item was in collections:
Mestrado em Agronomia Tropical (ID: 17)
No. of bitstreams: 1
Edfran N Andrade.pdf: 1316078 bytes, checksum: d702483f274a562c755b8cc3e56f3cff (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Dioscorea trifida, better known as yam, is the main species in the genus Dioscorea grown in the municipality of Caapiranga. The propagation of the species is held by segments of the tuber. Although Dioscorea trifida have all the reproductive organs, farmers do not use botanical seed in the planting system. Thus, we intend to verify the morphology and investigate sexual propagation in two landraces of Dioscorea trifida. Length, width, thickness, diameter and weight of the fruit and seeds of two landraces were determined. Consistency, color and surface of the forehead; manner, raphe position were the external morphological characteristics determined for fruits and seeds. Presence or absence, consistency, thickness and location of the endosperm, embryo, type, shape and color were the characteristics determined for internal morphological characteristics. To determine the type of reservation were used as reagents: Lugol, Sudam III and Xylidine ponceau. For testing emergency three substrates: fine sand + sawdust weathered, weathered sawdust and sieved forest humus were used. The characteristics evaluated were: germination percentage, average time and speed of emergence. The fruits of the two landraces are capsular type with three flat lobes. Each lobe contains a single seed. The exocarp is pilose, with short, hyaline trichomes; yellowish white before dehiscence, changing color to brown in the beginning of dehiscence. The endocarp is papyraceus, smooth and shiny. The seeds are alates, with peripheral asa; seminiferous central core, elliptical and tan brown. The integument is cartaceo, darker brown than the wing. The endosperm is solid, thick, tender and white coloring. The embryo is peripheral, ovoid and white colored. Reservations Dioscorea trifida seeds are formed by lipids. The emergence was low and time consuming for both landraces, being the best germination for landrace white yam with thin sand + weathered sawdust substrate (33.6%). The best result for the speed of emergence index (EVI) was observed for the white landrace in substrate composed of weathered sawdust. The mean emergence time varied between 43 to 50 days, with best performance recorded for the white yam in substrate composed of fine sand + sawdust tanned. / Dioscorea trifida, mais conhecida como cará, é a principal espécie do gênero Dioscorea cultivada no município de Caapiranga. A propagação da espécie é realizada por segmentos do tubérculo. Apesar de D. trifida possuir todos os órgãos reprodutivos, os agricultores não utilizam sementes botânicas no sistema de plantio. Dessa forma, pretende-se verifica os aspectos morfológicos e investigar a propagação sexuada de duas etnovariedades de D. trifida. Foram determinados comprimento, largura, espessura, diâmetro e peso do fruto e sementes das etnovariedades. As características morfológicas externas dos frutos e sementes foram: consistência, cor e superfície da testa; forma, posição rafe. Para as características morfológicas internas foram verificados: presença ou ausência, consistência, espessura e localização do endosperma, embrião, tipo, forma e cor. Para determinar o tipo de reserva utilizaram-se reagentes como: Lugol, Sudam III e Xylidine ponceau. Para os testes de emergência foram utilizados três substratos (areia fina + serragem curtida, serragem curtida e terriço de mata peneirado). As características avaliadas foram: porcentagem de emergência, tempo médio e velocidade de emergência. Os frutos das duas etnovariedades são do tipo cápsulas com três lóbulos achatados. Cada lóbulo apresenta uma única semente. O exocarpo é piloso, com tricomas curtos e hialinos; verde amarelado antes da deiscência, mudando a coloração para marrom no início da deiscência. O endocarpo é papiráceo, liso e brilhante. As sementes são aladas, com asa periférica; núcleo seminífero central, elípticas e marrom acastanhado. O tegumento é cartáceo, marrom mais escuro que a asa. O endosperma é contínuo, espesso, tenro e de coloração branca. O embrião é periférico, ovoide e de coloração branca. As reservas das sementes de D. trifida são formadas por lipídeos. A emergência foi baixa e demorada para as duas etnovariedades, sendo a melhor germinação para etnovariedade cará branco com o substrato areia fina + serragem curtida (33,6%). O melhor resultado para o índice de velocidade de emergência (IVE) foi observado para a etnovariedade cará branco no substrato composto por serragem curtida. O tempo médio de emergência variou entre 43 a 50 dias, sendo o melhor desempenho registrado para a etnovariedade cará branco no substrato composto por areia fina + serragem curtida.
|
8 |
Acquisition de connaissances sur la génétique de l'espèce Dioscorea alata L. pour la production de variétés polyploïdes. / Knowledge on the genetics of the species Dioscorea alata L. for the production of polyploid varietiesNémorin, Alice 29 June 2012 (has links)
Nous avons étudié les phénomènes de polyploïdisation chez l'igname Dioscorea alata qui comprend trois cytotypes diploïde (2n=40), triploïde (2n=60) et tétraploïde (2n=80) en vue d'optimiser les stratégies de production d'hybrides polyploïdes. Chez ce complexe polyploïde l'augmentation de la ploïdie est corrélée avec une augmentation de la vigueur et des rendements plus élevés et plus stables. Dans un premier temps nous avons démontré l'autotétraploïdie des variétés tétraploïdes à l'aide de trois approches différentes: des analyses d'hérédité de marqueurs microsatellites, l'observation de phénomènes de double réduction et l'étude des méioses des cellules mères de pollen. Nous avons ensuite déterminé quels sont les mécanismes les plus probables à l'origine des polyploïdes naturels via l'étude de la transmission de l'hétérozygotie parentale à l'aide de microsatellites et par l'étude des incompatibilités au niveau de l'albumen lors de différents croisements intracytotypes et intercytotypes en utilisant la cytométrie en flux. Les résultats obtenus montrent que les polyploïdes de D. alata seraient apparus via la formation de gamètes non réduits de clones diploïdes. Le pool triploïde se serait édifié et diversifié uniquement par voie femelle, du fait de la non viabilité des croisements intercytotypes et de la stérilité des femelles et mâles triploïdes. Le pool tétraploïde serait apparu par union de deux gamètes non réduits de clones diploïdes (polyploidisation sexuelle bilatérale). Par la suite ce pool aurait été diversifié via des croisements intercy / We studied polyploidisation phenomena in the yam Dioscorea alata that includes three cytotypes -diploid (2n=40), triploid (2n=60) and tetraploid (2n=80) -in order to optimise polyploid hybrid production strategies. In this complex polyploid, the increase in ploidy is correlated with an increase in vigour and higher and more stable yields. We first showed the autotetraploidy of tetraploid varieties using three different approaches: heredity analyses of microsatellite markers, the observation of double reduction phenomena, and the study of meiosis of pollen mother cells. We then determined the mechanisms most likely to be at the origin of natural polyploids through the study of the transmission of parental heterozygoty using microsatellites and the study of incompatibilities at the endosperm level at the time of different intracytotypic and intercytotypic crosses using flow cytometry. The results obtained reveal that the polyploids of D. alata probably appeared through the formation of non-reduced gametes of diploid clones. The triploid pool would then have been constituted and diversified through the female pathway as a result of the non-viability of intercytotypic crosses and the sterility of female and male triploids. The tetraploid pool would have appeared as a result of the union of two non-reduced gametes of diploid clones (bilateral sexual polyploidisation). This pool would then have diversified through intercytotypic crosses with the formation of 2n gamètes through both the female and the male pathway, as well as by intracytotypic crosses within the 4X pool.
|
9 |
Caracterização molecular de vírus que infectam inhame (Dioscorea spp.) no nordeste do BrasilLIMA, Joyce Silva 17 February 2012 (has links)
Submitted by (lucia.rodrigues@ufrpe.br) on 2017-03-17T14:50:17Z
No. of bitstreams: 1
Joyce Silva Lima.pdf: 2222741 bytes, checksum: 8a6c7b004633c1014edd4a6cdb6ce33f (MD5) / Made available in DSpace on 2017-03-17T14:50:17Z (GMT). No. of bitstreams: 1
Joyce Silva Lima.pdf: 2222741 bytes, checksum: 8a6c7b004633c1014edd4a6cdb6ce33f (MD5)
Previous issue date: 2012-02-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The yam crop (Dioscorea spp.) has a great socioeconomic importance for the Northeast region of Brazil, due to the excellent nutritional quality and energy of its tubers, with potential for export, especially for Europe. However information about the occurrence and distribution of yam viruses are limited in Brazil, the major constraints to yam production, are the viral pathogens. In this study, surveys were conducted to detect the occurrence of viruses yam in produtive areas in northeastern Brazil. The analysis of sequences of virus in yam leaf samples from Alagoas, Pernambuco and Paraiba states were evaluated using the molecular techniques polymerase chain reaction (PCR) and rolling circle amplification (RCA) which revealed the occurrence of badnavirus and geminivirus. Analyzing the partial nucleotide sequence in the RT/RNaseH encoding region, was observed that the isolates of badnavirus correspond to the species Dioscorea alata bacilliform virus (DaBV) and presented nucleotide sequences identity with 50 isolates of DaBV varying between 78-97%. It was also observed that a group with four isolates unrelated to any species of Badnavirus genus, indicating the possibility of being a new phytovirus genus or corresponding to endogenous sequence. Some samples showed the presence of a new begomovirus closely related to species that infect tomato and weeds. A curtovirus was also detected in yam samples and it was related to the described specie Beet mild curly top virus, not reported in Brazil in any host. These results suggest that DaBV is a widespread virus found in northeastern Brazil, the possible presence of endogenous sequences in yam and records the first report of geminivirus in yam and monocotyledonous in Brazil. / A cultura do inhame (Dioscorea spp.) apresenta grande importância socioeconômica para a região Nordeste do Brasil, devido à excelente qualidade nutritiva e energética de suas túberas, apresentando potencial de expansão via exportação de túberas, especialmente para a Europa. Patógenos virais estão entre os principais fatores que ameaçam a produção e produtividade de inhame e circulação segura de germoplasma, contudo informações sobre a ocorrência e distribuição de vírus de inhame são limitadas no Brasil. Neste estudo, as pesquisas foram conduzidas para detectar a ocorrência de viroses nas zonas produtoras do Nordeste do Brasil. A análise de um total de 425 amostras de folhas de inhame obtidas em áreas de cultivo, localizadas nos estados de Alagoas, Pernambuco e Paraíba foram avaliadas através das técnicas moleculares de reação em cadeia da polimerase (PCR) e amplificação em circulo rolante (RCA) que revelaram a ocorrência de badnavírus e geminivírus. Analisando a sequência parcial de nucleotídeos da região codificante RT/RNaseH observou-se que os isolados de badnavirus correspondem à espécie Dioscorea alata baciliforme virus (DaBV) e apresentam identidade de seqüências de nucleotídeos de 50 isolados de DaBV variando entre 78-97%. Constatou-se ainda um grupo de quatro isolados que não se relacionaram com nenhuma espécie do gênero Badnavirus, podendo constituir um novo gênero de fitovírus ou corresponder a sequências endógenas integradas. Em algumas amostras foi constatada a presença de um novo begomovirus estreitamente relacionado com espécies que infectam tomate e plantas daninhas. Um curtovirus também foi detectado nas amostras de inhame e relacionado com uma espécie já descrita Beet mild curly top vírus, ainda não relatada no Brasil em nenhum hospedeiro. Estes resultados sugerem a ampla disseminação do DaBV no Nordeste brasileiro e a possível presença de sequências endógenas em plantas de inhame e registra o primeiro relato de geminivírus na cultura do inhame e em monocotiledôneas em geral no Brasil.
|
10 |
Desenvolvimento de um revestimento comestível antimicrobiano a base de amido de inhame com quitosana na conservação da cenoura minimamente processada / Development of an edible antimicrobiano coating based on yam starch and quitosana on the conservation of the minimally processed carrotsDurango Villadiego, Alba Manuela 08 December 2004 (has links)
Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2016-11-03T17:18:19Z
No. of bitstreams: 1
texto completo.pdf: 669306 bytes, checksum: 9b386dbcaba82f69fd43166410e1d916 (MD5) / Made available in DSpace on 2016-11-03T17:18:19Z (GMT). No. of bitstreams: 1
texto completo.pdf: 669306 bytes, checksum: 9b386dbcaba82f69fd43166410e1d916 (MD5)
Previous issue date: 2004-12-08 / O objetivo deste trabalho foi desenvolver um revestimento comestível a base de amido de inhame “caramujo" adicionado de quitosana, como antimicrobiano, e avaliar seu efeito na conservação de cenoura minimamente processada. O amido foi extraído dos tubérculos e sua composição físico-química e propriedades reológicas foram determinadas. Raizes de cenoura “Brasília”, foram fatiadas em rodelas e minimamente processadas. Foram preparados filmes e revestimentos a partir de soluções aquosas de 4% de amido de inhame (p/p) + 2% de glicerol (p/p), 4% de amido de inhame (p/p) + 2% de glicerol (p/p) + quitosana nas concentrações de 0,5, 0,75, 1,0 e 1,5%. As amostras de cenouras foram imersas nos revestimentos durante 3 minutos e secas a 20°C por 3 horas. As amostras do grupo controle foram imersas em água destilada esterilizada. Todas as amostras foram acondicionadas em bandejas de poliestireno expandido, envoltas em filme de poli (vinil cloreto) e estocadas a 8 ± 2°C por 15 dias. Foram realizadas análises microbiológicas, perda de massa, índice de esbranquiçamento, aceitabilidade de cor e sabor com 0, 5, 10 e 15 dias de estocagem. Os filmes foram formados pelo método “casting” e sua permeabilidade ao vapor de água foi determinada. O rendimento da extração do amido a partir dos tubérculos foi de 9,3%. Os componentes físico- químicos, em base seca, foram de 11,57% de umidade, 0,64% de proteínas, 0,052% de matéria graxa e 0,17% de cinzas. Os conteúdos de amido e de amilose foram de 99,17% e 22%, respectivamente. A temperatura inicial de pasta foi de 60,3oC e a máxima temperatura de viscosidade foi de 98,5oC, apresentando baixa tendência a retrogradação (100 UA). Os filmes produzidos foram visualmente transparentes com espessura de 30 ± 5 μm com valores de permeabilidade ao vapor de água entre 4,58 g mm kPa-1 d-1 m-2, para o filme de amido e glicerol, e 3,57 g mm kPa-1 d-1 m-2, para o filme de amido+glicerol+1,5% de quitosana, respectivamente. permeabilidade Os valores de foram estatisticamente diferentes (P<0,05) entre eles. A permeabilidade ao vapor de água dos filmes diminuiu com o aumento do teor de quitosana. Para a sanitização da cenoura em rodelas foi utilizada a concentração de 200 mg/L de cloro residual total, que se apresentou como a mais eficiente para o controle de coliformes totais e fecais e aeróbios mesófilos. O tempo ideal de centrifugação para amostras contendo 1500 g de cenoura em rodelas foi de 6 minutos, quando se utilizo centrífuga doméstica (ARNO) e 3,5 minutos para amostras contendo 3000 g quando foi usada centrífuga industrial. Nas fotomicrografias foi observado que os revestimentos apresentaram distribuição homogênea sobre a superfície da cenoura com uma espessura entre 15 a 20 μm. Os revestimentos apresentaram efeito significativo (P<0,05) para o controle de coliformes totais, psicrotróficos, fungos filamentosos e leveduras e nos atributos cor, sabor e índice de esbranquiçamento. Entretanto, não apresentaram diferença significativa (P>0,05) para perda de massa. Durante o armazenamento, todas as amostras apresentaram contagens <3 NMP/g para coliformes fecais e Escherichia coli e ausência de Salmonella sp em 25/g. Os revestimentos que continham quitosana apresentaram efeito antimicrobiano para coliformes totais, psicrotróficos, fungos e leveduras. O revestimento com 1,5% de quitosana apresentou a melhor eficiência sobre esses grupos microbianos com reduções de 2,1, 1,83 e 3,64 ciclos log, respectivamente, em relação ao controle. O grupo controle e as amostras revestidas somente com amido e glicerol apresentaram contagens mais altas dos grupos de microrganismos avaliados durante a estocagem. No tempo zero de estocagem, os revestimentos que continham quitosana mantiveram melhor a cor da cenoura, obtendo as notas hedônicas mais altas. Após 15 dias de estocagem, o revestimento de amido e glicerol, obteve a nota mais alta (7,4) para o atributo cor, enquanto que o grupo controle (sem revestimento) apresentou nota 4,7. Quanto ao sabor, as amostras revestidas com amido e glicerol também obtiveram a maior nota (6,5). Notas em torno de 5 foram obtidas para o controle e amostras revestidas com amido e quitosana. Para o índice de esbranquiçamento, as amostras revestidas não difereram entre elas e difereram do controle. O menor índice de esbranquiçamento foi de 37,6, apresentado pela amostra revestida com amido e 1,5% de quitosana, em comparação a 44,2, apresentado pelo grupo controle. O amido de inhame apresentou-se como uma boa fonte para a produção de filmes e revestimentos comestíveis, com grande potencial de aplicação na indústria de alimentos, com a vantagem de serem biodegradáveis. O uso do revestimento comestível antimicrobiano, constituído de amido de inhame e quitosana é uma alternativa viável para controlar o crescimento microbiano, manter a cor, retardar o aparecimento do esbranquiçamento na cenoura minimamente processada e estender a vida de prateleira do produto. / This work aimed to develop an edible coating from yam starch incorporated with chitosan, as an antimicrobial compound, and to evaluate its effect on minimally processed carrots conservation. The starch was extracted from yam and had characterized its physical, chemical and reological properties. Brazilian variety carrots were sliced and minimally processed. Films and coatings were prepared as the following composition: 4% yam starch (p/p) + 2% glycerol (p/p), 4% yam starch (p/p) + 2% glycerol (p/p) added with 0,5, 0,75, 1,0 and 1,5 % of chitosan. Samples of sliced carrots were immersed into these coatings for 3 minutes and dried at 20oC/ 3 hours. The control samples were immersed into pure water. All the samples were acondicionated in polystyrene trays, wrapped in polyvinyl cloride and stored at 10oC during 15 days. Microbiological analyses, mass loss, whitish index, sensorial evaluation of color and flavor were realized at 0, 5, 10 and 15 days of storage. The casted films had its vapor permeabilities determined. The starch presented the following characteristics: yield of 9,3%, humidity content of 11,57%, proteins content of 0,64%, lipids:0,052%, ash:0,17%, starch:99,17% and amylose:22%. The gel initial temperature was 60,3oC and the temperature of maximum viscosity was of 98,50C, showing a low tendency for retrogradation (100 UA). The films with thickness of 30± 5μm showed transparency and presented a vapor permeability ranging from 4,58 g.mm.dia-1.m-2.KPa-1, for starch-glycerol film, to 3,57 g.mm.dia-1.m-2.KPa-1, for the film containing 1,5% of chitosan + starch +glycerol. The permeabilities values showed significant (p<0,05) difference among them. The film permeability decreased as the chitosan level in the film increased. The concentration of 200 mg/L of total residual clorine was used for carrots sanification treatment and, among the others treatments, presented the highest efficiency on coliforms and mesophilics aerobes inhibition. The centrifugation time for 1500 g of sliced carrots was 6 minutes for houseware centrifuge and 3.5 minutes for industrial centrifuge. Photomicrografies from the coated carrots showed a homogeneous distribution of the coating on the carrots and a thickness ranging from 15 to 20 μm . The coatings showed a significant (P<0,05) effect on microbiological control of coliforms, psychrotrophic and fungi as well as in the sensorial evaluation of color and flavor and whitiness index, but did not showed significant difference for mass loss ( P<0,05) During storage period, all the samples presented countings <3NMP/g for coliforms fecal and E. coli and no presence of Salmonella in 25 g. The edible coatings with chitosan inhibited the microrganisms growth. Coating containing 1,5% of chitosan reduced 2,1, 1,83 and 3,64 log cycles for coliforms, psychrotrophic and fungi and yeast, respectively, compared with the control. The control group and the samples coated with starch and glycerol showed the highest microorganisms countings evaluated during the storage period. Chitosan-coatings protected carrots against color loss at the beginning of the storage, but at the end the treatment with starch and glycerol obtained the highest score for color attribute. For flavor sensorial analyses, this treatment also was evaluated by the painelist and obtained the highest score (6,4) compared with the control and the chitosan-starch treatments (5,0). The whitish index was lower for the chitosan 1,5% (37,6) compared with the value of 44,2 showed in the control treatment. The yam starch presents as a good source for production of edible coating and film with a potential availability for food industry. The edible coating incorporated with chitosan demonstrated to be a barrier hurdle for food preservation, inhibiting microorganism growth, decreasing color loss and whitish index of the minimally processed carrots and, therefore, increase its shelf-life.
|
Page generated in 0.0309 seconds