• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 35
  • 24
  • 10
  • 6
  • 5
  • 1
  • Tagged with
  • 93
  • 93
  • 35
  • 35
  • 13
  • 10
  • 10
  • 9
  • 9
  • 9
  • 7
  • 7
  • 7
  • 7
  • 7
  • 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.
21

Produção, caracterização e avaliação ecônomica de destilados de batata doce

Weber, Caroline Trevisan January 2017 (has links)
A batata-doce possui grande importância na alimentação humana e expressivo potencial para produção de etanol. A produção brasileira desta cultura é a 20ª no ranking mundial, com produção de 525.814 t em 2014, destacando-se o Rio Grande do Sul, responsável por 30,68% da produção do país. Shochu é a bebida alcoólica destilada mais consumida no Japão, produzida por destilação de fermentados de diversas fontes amiláceas, incluindo a batata-doce. Em sua fabricação é utilizado o koji, cultura sólida de fungos tradicional dos países asiáticos, mas que torna o processo produtivo lento e com alto risco de contaminação. Considerando a alta produtividade de batata-doce e a influência da cultura japonesa no Brasil, principalmente na culinária, percebe-se uma grande oportunidade de agregar valor a essa matéria-prima. Os objetivos deste trabalho são fazer o estudo de um processo alternativo - mais rápido e com menor risco de contaminação - para produção de destilado de batata-doce similar ao shochu, e a avaliação da viabilidade econômica para produção do mesmo. No processo alternativo proposto, o koji foi substituído pela enzima Stargen 002, mistura contendo alfa-amilase e glucoamilase, e utilizou-se uma pectinase para redução da viscosidade do meio. O tempo de processo reduziu de 14 dias para apenas 1 dia. As análises dos compostos de interesse foram realizadas por HPLC e GC. Quanto às matérias-primas, o teor de açúcares redutores totais foi maior na batata-doce de casca creme e polpa creme (30,42±1,54%), seguida pela batata-doce de casca púrpura e polpa creme (27,44±0,36%) e por último a batata-doce de casca rosada e polpa alaranjada (20,57±0,49%), e o teor de umidade seguiu a ordem inversa. Os resultados obtidos pelo processo padrão não foram satisfatórios em razão do baixo rendimento da fermentação alcoólica (40,59-42,51%) e da formação de compostos acima do limite da legislação, resultantes de fermentação acética. O rendimento experimental da fermentação alcoólica foi maior utilizando a levedura Angel Thermal Resistance Alcohol® (73,65%), seguida da Lalvin DV10® (70,39%) e por último a Lalvin EC1118® (67,31%), sendo maiores do que os obtidos com o uso das técnicas convencionais de produção de shochu, pois a não contaminação por bactérias acéticas no fermentado possibilitou maior rendimento em etanol. Por destilação em batelada, foram separadas frações de cabeça, coração e cauda, e em todas elas o componente álcool metílico mostrou-se acima dos limites da legislação. Realizou-se, então, experimento sem adição de pectinase, e o problema de formação de metanol foi eliminado. Entretanto, houve queda no rendimento da fermentação alcoólica (51,65-54,75%), indicando que a menor desintegração da batata-doce prejudica o andamento do processo fermentativo. Todos os compostos analisados mostraram-se dentro dos limites das normas vigentes. As frações cabeça e cauda foram descartadas e a fração coração foi diluída até teor alcoólico de 25% (v.v-1) e envasada. O destilado produzido, batizado de “Tchêchu”, e o shochu comercial apresentaram as mesmas bandas de adsorção em análise FTIR, identificando semelhança entre os mesmos. O custo de produção de uma garrafa (750 mL) de “Tchêchu” foi estimado em R$ 8,75. Com preço unitário de R$ 15,75 e utilizando-se a taxa SELIC (9,25% a.a.) como taxa mínima de atratividade, tem-se VPL de R$ 1.815.107,34, TIR de 26%, e payback descontado de 2,44 anos, o que mostra que a implantação de uma destilaria para produção de “Tchêchu” é economicamente viável. / Sweet potatoes have great importance in human food and have significant potential for ethanol production. The Brazilian production of this crop is the 20th in the world ranking, with production of 525,814 t in 2014, standing out Rio Grande do Sul, responsible for 30.68% of the country's production. Shochu is the most widely consumed spirit in Japan, produced by the distillation of fermented mash from a variety of starchy sources, including sweet potatoes. In its manufacture is used koji, a solid fungus culture traditional of the Asian countries, but that makes the productive process slow and at high risk of contamination. Considering the high productivity of sweet potatoes and the influence of Japanese culture in Brazil, a great opportunity to add value to this raw material is perceived. The objectives of this work are to study an alternative process - faster and with less risk of contamination - for the production of sweet potato distillate similar to shochu, and to study the economic viability analysis for its production. In the alternative process proposed, koji was replaced by the enzyme Stargen 002, a mixture containing alpha-amylase and glucoamylase, and a pectinase was used to reduce the viscosity of the medium. The process time reduced from 14 days to only 1 day. Analyzes of the compounds of interest were performed by HPLC and GC. Total reducing sugar content was higher in sweet potatoes with cream peel and cream pulp (30.42 ± 1.54%), followed by sweet potatoes with purple peel and cream pulp (27.44 ± 0.36%) and finally sweet potatoes with rose peel and orange pulp (20.57 ± 0.49%), and the moisture content followed the reverse order. The results obtained by the standard process were not satisfactory due to the low yield of alcoholic fermentation (40.59-42.51%) and the formation of compounds above the limit of the legislation, resulting from acetic fermentation. The experimental yield of alcoholic fermentation was higher using Angel Thermal Resistance Alcohol® (73.65%), followed by Lalvin DV10® (70.39%) and Lalvin EC1118® (67.31%), being higher than those obtained with the use of conventional methods of shochu production, since the non-contamination by acetic bacteria in the fermentation allowed a higher yield in ethanol. Fractions of head, heart and tail were separated by distillation, and in all of them the methyl alcohol component showed above the limits of the legislation. An experiment was performed without addition of pectinase, and the problem of methanol formation was eliminated. However, there was a decrease in the yield of alcoholic fermentation (51.65-54.75%), indicating that lower disintegration of sweet potatoes impairs the progress of the fermentation process. All compounds analyzed were within the limits of the current laws. Head and tail fractions were discarded and heart fraction was diluted up to 25% alcoholic strength (v.v-1) and bottled. The distillate produced, named "Tchêchu", and commercial shochu presented the same adsorption bands in FTIR analysis, identifying similarity between them. The cost of producing a bottle (750 mL) of "Tchêchu" was estimated at R $ 8.75. With a unit price of R$ 15.75 and using the SELIC rate (9.25%) as minimum acceptable rate of return there is a NPV of R$ 1,815,107.34, an IRR of 26%, and a discounted payback of 2.44 years, which shows that the implementation of a distillery to produce "Tchêchu" is economically viable.
22

Household consumption of orange - fleshed sweet potato and its associated factors in Chipata district, Eastern province, Zambia

Sakala, Patricia January 2017 (has links)
Magister Scientiae (Nutrition Management) - MSc(NM) / Orange-fleshed sweet potato consumption promotion is one of the key nutrition sensitive interventions implementedto address high vitamin A deficiency among the rural population of Zambia since 2011. However, to date no study has been completed regarding household consumption of orange-fleshed sweet potato and factors related to their consumption. The study detailed here therefore sought to establish the consumption of orange-fleshed sweet potato, and to identify factors associated with its household consumption in the Integrating Orange Project areas in Chipata district of Zambia. The study randomly sampled 295 households, and collected information on the household characteristics, production, procurement, consumption and knowledge on orange-fleshed sweet potato. Cross tabulation chi square and one-way analysis of variance were used to identify associated consumption factors. The study found that 86.8% of the households ate orange-fleshed sweet potato; 49.5% ate it 1 to 3 days per week and 30.2% ate it at least 4 or more days per week, and only 13.2% did not consume orange-fleshed sweet potato at all. A relationship was found between having children younger than five years old and consumption of orange-fleshed sweet potato (P < 0.001). Results showed that 8.7% of households with children (n=183) never ate orange-fleshed sweet potato, versus 20.5% of households without children (n=112). Production of orange-fleshed sweet potato (n=178) was found to have a relationship with household conusmption of orange-fleshed sweet potato (P < 0.001). Only 1.1% of households that produced orange-fleshed sweet potato did not consume any, versus 31.6% who did not produce orange-fleshed sweet potato. Purchasing of orange-fleshed sweet potato (n=118) was found to have a relationship with its household consumption (P < 0.001); 56.2% of the households that ate orange-fleshed sweet potato 1 to 3 days during the previous week bought it, compared to only 27.0% of households who ate orange-fleshed sweet potato more than 4 days per week among those that bought it. The respondent‘s knowledge of the health benefits of orange-fleshed sweet potato was found to have a relationship with its consumption in the household (P < 0.001). Only 7.8% of the households where respondents knew the benefits of orange-fleshed sweet potato (n=215) never ate orange-fleshed potato, compared to 50.0% of households where the respondents did not know any benefit (n=80). In contrast, 33.5% of the households where the respondents knew the health benefits ate orange-fleshed sweet potato at least 4 days a week compared to only 7.9% of households where the respondents did not know any benefit. Overall, the study showed that most households consumed orange-fleshed sweet potato. The highconsumption might be due to seasonality, as the study was done during the harvesting season of orange-fleshed sweet potato. Also, prodcution of orange-fleshed sweet potato was promoted in the study area through the Integrating Orange Project. These results therefore suggest that projects seeking to promote consumption of orange-fleshed sweet potato as an intervention for vitamin A deficiency control should promote production of orange-fleshed sweet potato and sensitization of communities on the health benefits of orange-fleshed sweet potato consumption.
23

The Vitamin C Content of Eight Varieties of Sweet Potatoes and the Effect of Cooking on the Vitamin Content

Eakle, Dorothy January 1942 (has links)
Since sweet potatoes, which also furnish vitamin A, are a common food in the popular diets of Texas and are so generally grown over the state, the purpose of this study is (1) to ascertain the amount of vitamin C in eight of the varieties most commonly grown and (2) to determine the effect of the three most popular methods of cooking (boiling, baking, and candying) on the vitamin C content of these varieties of sweet potatoes.
24

The Vitamin A Content of Dehydrated Sweet Potato Made from the Freshly Harvested Puerto Rico Variety

James, Catherine January 1941 (has links)
The purpose of this study was to determine by biological method of assay the vitamin A content of Puerto Rico sweet potatoes which were dehydrated immediately after harvesting.
25

Mandioca, batata-doce e araruta como matérias primas para obtenção de amidos fosfatados /

Melo, Marília Sbragia Del Bem January 2019 (has links)
Orientador: Magali Leonel / Resumo: O presente estudo objetivou caracterizar amidos de mandioca, batata-doce e araruta quanto às propriedades físico-químicas e modificar estes amidos quimicamente visando à obtenção de amidos fosfatados. No processo de modificação os amidos foram fosfatados com trimetafosfato de sódio e tripolifosfato de sódio durante diferentes tempos de reação. Os amidos nativos e modificados das três fontes botânicas foram analisados quanto aos teores de fósforo e de amilose, padrão de difração de raio-X, cristalinidade relativa, morfologia e tamanho dos grânulos, poder de inchamento, solubilidade, propriedades de pasta e térmicas. Os amidos nativos diferiram quanto às características morfológicas e físico-químicas. Todos os amidos mostraram baixo teor de fósforo. O amido de batata-doce apresentou maior cristalinidade e teor de amilose, enquanto o amido de araruta apresentou maior tamanho de grânulos, poder de inchamento, solubilidade e maior instabilidade frente às forças mecânicas. Independentemente da fonte botânica, a modificação química aumentou os teores de fósforo dos amidos com alterações das características morfológicas e propriedades físico-químicas. O aumento do tempo da reação de fosfatação aumentou o diâmetro médio dos grânulos, sendo observada menor uniformidade dos grânulos. Além disso, ocorreram mudanças como diminuição da cristalinidade relativa, aumento do poder de inchamento e quebra de viscosidade dos géis. Por outro lado, a modificação química alterou as propriedades de p... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor
26

Preliminary Evaluation of Antioxidant Compounds and Antioxidant Capacity of 15 Cultivars of Sweet Potato (Ipomoea batatas) and Sweet Potato Fries

Dai, Shun 01 October 2018 (has links)
No description available.
27

Preharvest ethylene and postharvest curing effects on baked sweet potato (Ipomoea batatas L. Lam) quality and prevention of sprouting on cured sweet potatoes

Sheibani, Ershad 06 August 2011 (has links)
The effect of preharvest foliar applications of ethephon and postharvest curing on baked sweet potatoes (Ipomoea batata) were analyzed. Ethylene had negative effects on appearance of baked roots while curing increased the total phenolics in sweet potatoes. Panelists preferred the non-ethylene treated and green or cured over ethylene treated sweet potatoes with respect to texture, color and flavor. No differences in chemical or color properties were found between treatments. The effect of curing time (0, 7, 14 days) on baked sweet potatoes was studied. Curing caused more browning on flesh of sweet potatoes. Moreover, panelists preferred the texture of the green over the cured roots but did not find any differences in flavor sensory quality. The effect of hot water treatment on sprouting and spoilage of cured sweet potatoes was investigated. The most effective treatment was at 53-56 °C for less than 10 min, resulting in less than 60% (control=80%).
28

Impact of daily sweet potato ingestion on alterations to the gut microbiome, cholesterol, and exercise performance

Smith, JohnEric William 12 May 2023 (has links) (PDF)
The importance of the gut microbiome is being explored in relation to multiple facets of health and performance. The purpose of this study was to explore the impact of frequent sweet potato ingestion on alterations of the gut microbiome which might in turn alter cholesterol levels and exercise performance. Thirteen recreationally trained males had fecal and blood samples collected and exercised to fatigue with and without exogenous carbohydrate ingestion prior to and following 42 days of daily sweet potato ingestion. Bacterial communities were extracted from fecal samples and bacterial DNA were sequence. Blood samples were analyzed for total cholesterol, low-density lipoprotein-C, high-density lipoprotein-C, and triglycerides. Performance was analyzed comparing changes in time-to-volitional fatigue with and without carbohydrate ingestion. Changes were observed in microbial abundance following 42 days of sweet potato ingestion but no differences in cholesterol or cycling fatigue with and without carbohydrates.
29

Inserción de genes cry3Ca1 y cry7Aa1 en Ipomoea batatas (L.) Lam. cv. Huachano para conferir resistencia a Cylas puncticollis y C. brunneus “gorgojos del camote” (Coleoptera: Curculionidae)

Reaño Cabrejos, Romina January 2013 (has links)
Con la finalidad de insertar los genes cry3Ca1 y cry7Aa1 en Ipomoea batatas (L.) Lam. cv. “Huachano” para conferir resistencia a Cylas puncticollis y C. brunneus “gorgojos del camote”, se desarrolló la transformación genética mediada por Agrobacterium tumefaciens, siguiendo dos protocolos de regeneración y transformación. Partiendo de 46 meristemos y 282 hojas con peciolo, se obtuvieron 8 eventos transgénicos de inserción completa del ADN - T (4 por cada protocolo de transformación) y un evento de inserción incompleta. Con una eficiencia de transformación de 8.70%, el protocolo a partir de meristemos demostró ser más eficaz en la obtención de eventos transgénicos de inserciones completas que el protocolo a partir de hojas con peciolo, con el cual se obtuvo una eficiencia de transformación de 1.42%. A su vez, los regenerantes fueron evaluados mediante pruebas in vitro (resistencia a kanamicina) y moleculares (PCR), con los análisis de PCR se confirmó que los 8 regenerantes callo positivos (resistentes a la prueba de kanamicina) también presentaron la inserción de los transgenes de interés “cry3Ca1 y cry7Aa1” y del gen marcador selector “nptII”. Asimismo, se determinó que 4 de los eventos transgénicos integraron secuencias externas al ADN - T “backbone” en el genoma de la planta, uno de los cuales, presentó la inserción del gen bacteriano “virD2”.With the purpose of inserting the genes cry3Ca1 and cry7Aa1 in Ipomoea batatas (L.) Lam. cv. "Huachano" to develop resistance to Cylas puncticollis and C. brunneus “sweet potato weevils”, the genetic transformation was developed using Agrobacterium tumefaciens, following two protocols of regeneration and transformation. Starting from 46 meristems and 282 leaves with petiole, 8 transgenic events were obtained with complete insertion of T - DNA (4 for each transformation protocol) and one event with incomplete insertion. With an efficiency of transformation of 8.70 %, the protocol of meristems proved to be more effective in obtaining transgenic events of complete inserts than the protocol of leaves with petiole, which obtained a efficiency of transformation of 1.42 %. The regenerants were evaluated by testing in vitro (resistance to kanamycin) and molecular (PCR), the PCR analysis confirmed that the 8 regenerants positive callus (resistant to kanamycin test) also presented the insertion of transgenes of interest “cry3Ca1 and cry7Aa1” and selection marker gene “nptII”. Likewise, 4 of the transgenic events integrated sequences outside the T - DNA “backbone” into the plant genome, one of whom, showed the insertion of the bacterial gene “virD2”.
30

Anthocyanin-enriched purple sweet potato for colon cancer prevention

Lim, Soyoung January 1900 (has links)
Doctor of Philosophy / Department of Human Nutrition / Weiqun Wang / Anthocyanins are flavonoid pigments that account for the purple color in many plant foods. It has been investigated that anthocyanins’ predominant occurrences in human diet and their health beneficial activities such as antioxidant, anti-inflammatory, and anti-carcinogenetic effects. Based on those scientific evidences, anthocyanins are now recognized as potential therapeutic compounds. Particularly, the chemopreventive effect of anthocyanins has been widely studied by many researchers in nutrition. However, their bioactivities are diverse due to different chemical structures of anthocyanins from different sources. In this study, we discuss the chemopreventive activity of anthocyanins from purple sweet potato. Previously, we selected a purple-fleshed sweetpotato clone, P40, crossbred seeds obtained from the International Potato Center in Lima, Peru. We hypothesized that anthocyanins enriched P40 may provide health beneficial activities in cancer prevention. For the first part of this study, we analyzed nutrient compositions, dietary fiber content, anthocyanins contents, total phenolics contents and total antioxidant activity. Even thought P40 presents similar composition and amount of nutrients with the control cultivars, white-fleshed O’Henry and yellow-fleshed NC Japanese, HPLC-MS analysis confirmed that it possesses much higher anthocyanin content even up to 7.5g/kg dry matter. Also, dietary fiber, particularly soluble dietary fiber content, total phenolics content, and total antioxidant capacity of P40 were significantly higher. For the second part of the study, we tested the potential anticancer characteristic of P40 cultivar in human colonic SW480 cancer cells and in azoxymethane-induced aberrant crypt foci in mice. Treatment with 0 – 40 μM of peonidin-3-glucoside or P40 extract containing corresponding amount of anthocyanins resulted in inhibition of cell growth in a dose-dependent manner. Interestingly, even though the patterns of growth inhibition were similar in the two treatment groups, the cells treated with P40 extract tend to survive significantly less than those treated with peonidin-3-glucoside. Cell cycle analysis confirmed that the growth inhibition was not due to cytotoxicity, but cytostatic mechanism with increased number at the G1 phase of the cell cycle. The cell cycle arrest was also significantly correlated with the anthocyanin contents in P40 cultivar when compared with the white-fleshed O’Henry and yellow-fleshed NC Japanese controls. After Azoxymethane (AOM) or saline injected mice were fed basal AIN-93M diet or diets containing 10~30% of P40, 20% O’Henry or 20% NC Japanese for 6 weeks, aberrant crypt foci (ACF) multiplicity was significantly inhibited by 10~30% P40 diet. Imunohistochemistry results of colonic mucosa showed that the expression level of apoptosis marker, caspase-3, was significantly induced in the mice treated with 10~20% P40 diet. Also, PCNA expression level, which is proliferation marker, was significantly inhibited by the 30% P40 diet. These findings indicated that consuming a purple sweet potato, P40, may prevent colon cancer by modulating antioxidant status, inducing apoptosis, and reducing cell proliferation.

Page generated in 0.044 seconds