• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 6
  • 4
  • 2
  • Tagged with
  • 12
  • 5
  • 4
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 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.
1

Contribution of enzymes and other components in food in the formation and destruction of volatile compounds.

Mirondo, Rita Akinyi January 2016 (has links)
No description available.
2

Remote sensing of Harmful Algal Blooms (HABs) in water bodies of Vhembe district area, Limpopo province, South Africa

Munyai, Linton Fhatuwani 20 September 2019 (has links)
MENVSC / Department of Ecology and Resource Management / Satellite remote sensing techniques have been proved to be the best methods for quantifying chlorophyll-a levels by estimating algal concentrations in water bodies. Harmful algal blooms (HABs) are posing a significant threat to the many water bodies in South Africa. This study aims at developing remote sensing solution to estimate chlorophyll concentrations in water bodies of Vhembe district municipality using recently launched Landsat 8 OLI. It is the first study to provide quantitative water quality information for the Vhembe region’s water bodies from a time series of satellite remotely sensed data and in-situ laboratory data. The objectives of this study was to evaluate spatial and temporal distributions of algae in water bodies and fish-ponds, to assess water quality parameters, namely: chlorophyll-a and turbidity and to compare data obtained from satellite remote sensors with in situ data. The 30 meters spatial resolution multispectral Landsat 8 OLI for 2016, 2017 and 2018 were used to derive chlorophyll-a estimate from an existing model at three water bodies. The chlorophyll-a concentrations measured during in-situ were employed to validate the Landsat derived chlorophyll-a estimates. The results from this study shows that Landsat derived chlorophyll-a estimates are correlating with field measurements. In all the reservoir, it was detected that there is low content of harmful algal blooms and thus the water bodies are in good condition since the chlorophyll-a concentrations were very low (ranging from 0 to 0.6 mg.m-3). In conclusion, it can be stated that Landsat 8 OLI sensor has the potential to map inland water bodies dominated with algal blooms at certain extent. It can further be stated that Landsat 8 OLI is suitable for monitoring the growth of HABs in aquatic ecosystem and is cost effective. This study also evaluated the potential of Banana peels powder and K2SO4 to inhibits the growth of algae (batch experiment). The water samples were collected at Tshifulanani and Lwamondo fish ponds where there are floating algae. The samples were collected seasonally and analysed for pH, water temperature, Total Dissolved Solids, Electrical conductivity, Dissolved Oxygen, turbidity, chlorophyll-a and absorbance. From the laboratory experiments, there was a variation in the values of absorbance (0.936A-1.234A), PH (7.1-8.3), EC (63.1- 87.9 μs/cm), TDS (52.6-69.7mg/L), water temperature (25.5-29.3°C) and Dissolved oxygen (5.3-7.1mg/L). The concentration of chlorophyll-a for Tshifulanani and Lwamondo fish ponds ranges were (2.14-15.96 mg/m-3) and (0.65-15.66 mg/m-3) respectively. A batch experiment was conducted to determine the potential of banana peels powder on inhibition of algal blooms in water samples by measuring absorbance at 750nm. It can be concluded in this study that banana peels have a potential to inhibits the growth of algae in fish ponds. The Absorbance has shown a rapid v decrease from 0.936A to Zero from day 1 to day 7 respectively. The inhibition of cyanobacteria by banana peels is followed using Potassium sulphate in treating the algal blooms in water samples. Both banana peels and potassium Sulphate has shown a positive response in treatment of algae on the batch experiment. The results of this study revealed that high concentration of physico-chemical parameters promote the growth of cyanobacteria in fish ponds but does not have negative effects on the fish except the oxygen competition with algal blooms. The statistical analysis in correlating the chl-a field measurements and remotely sensed data showed a positive outcome where K values were very high from 70% to 89%. These results show high level of agreement of correlation values of field chlorophyll-a concentration and satellite remotely sensed variables. / NRF
3

Ethanol Production from Cellulosic Biomass by Encapsulated Saccharomyces cerevisiae

Talebnia, Farid January 2008 (has links)
Unstable oil markets with rising environmental concerns have revived widespread interest in production of fuel ethanol from renewable materials. Cellulosic materials are abundant and prominent feedstocks for cheap ethanol production. However, due to recalcitrant structure of these materials, pretreatment is a prerequisite. Depending on the biomass, pretreatment and hydrolysis conditions, a number of degradation products and/or toxic components may be released that show strong inhibitory effects on the fermenting microorganisms. This thesis deals with application of encapsulation technology to ferment the highly toxic hydrolyzates without further pretreatment. Free cells could not tolerate presence of 5 g/l furfural in defined medium, and inhibitors in wood and peel hydrolyzates in batch mode of operation and fermentation failed. Continuous cultivation of wood hydrolyzate was only successful at 0.1 h−1 and the majority of cells lost their viability after 5 retention times. Encapsulated cell system could successfully ferment the synthetic medium containing 5 g/l furfural during sequential batch cultivations with ethanol yield of 0.41-0.42 g/g. Cultivation of undetoxified hydrolyzates was also carried out, where glucose and mannose were converted within 10 h without significant lag phase. However, a gradual decrease in cell activity was observed in sequential batches. Continuous cultivation was more successful, and wood hydrolyzate was fermented to ethanol by encapsulated S. cerevisiae at dilution rates up to 0.5 h−1. More than 75% of the encapsulated cells were viable in the worst conditions. Ethanol was produced with yield 0.44 g/g and specific productivity 0.14–0.17 g/g•h at all dilution rates. Contrary to wood hydrolyzate, where there is no preference for permeation of sugars or inhibitors through the capsules’ membrane, encapsulation technology was applied to eliminate inhibition of limonene in fermentation of orange wastes to ethanol. The capsules’ membrane, of hydrophilic nature, is practically impermeable to hydrophobic compounds such as limonene while allowing penetration of nutrients and products. While presence of 0.1% v/v limonene in the medium results in strong inhibition or even failure of cultivation with free cells, using this technique allowed fermentation of a medium containing 1.5% v/v limonene. The impact of encapsulation on the anaerobic growth pattern, morphological and physiological changes of S. cerevisiae over long-term application was investigated. The growth rate, total RNA and protein content of the encapsulated cells decreased gradually over repeated batch cultivations, while stored carbohydrates content increased. Within 20 batch cultivations, total RNA and protein content of encapsulated cells decreased by 39% and 24%, whereas glycogen and trehalose content increased by factors of 4.5 and 4, respectively. / <p>Akademisk avhandling som för avläggande av teknologie doktorsexamen vid Chalmers tekniska högskola försvaras vid offentlig disputation den 18 april 2008.</p>
4

Avaliação do processo de obtenção de farinha da casca de banana (Musa sapientum) das variedades Prata, Pacovan e Maçã / Process evaluation to produce banana (Musa sapientum) flour from peels of fresh fruit varieties Prata, Pacovan and Apple.

Pessoa, Thayze Rodrigues Bezerra 30 September 2009 (has links)
Made available in DSpace on 2015-04-17T14:49:33Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1540714 bytes, checksum: 6bdb44997d3913ccd4bc5f3c99084999 (MD5) Previous issue date: 2009-09-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This work aimed to study the drying process of banana (Musa sapientum) peels (varieties Prata, Pacovan and Apple). The convective drying was performed at various air temperatures (40°C to 60°C) and at an average air speed of 1.0 m/s. It was used a fixed bed dryer with upward flow of air. The tests were conducted until the sample reached equilibrium between its own moisture and the drying air humidity. The drying kinetics was evaluated by the Fick, empirical two parameters exponential and Page semi-empirical models. From these models were found the water diffusivities. They were in the order of 10-10m/s². Overall diffusivities increased with drying air temperature. The highest drying rates were obtained for the banana peels from varieties Apple, Prata and Pacovan, respectively. Final product quality was evaluated through the following analysis: enzymatic activity, minerals and water activity. The best drying condition, which generated a final product with better quality, was at 60°C of air temperature for the three varieties. / O presente trabalho teve como objetivo estudar o processo de secagem das cascas de banana Prata, Pacovan e Maçã (Musa sapientum) in natura. A secagem convectiva foi realizada a várias temperaturas (40°C a 60°C) do ar de secagem com velocidade média (1,0 m/s) do ar. Para tal, foi utilizado secador de leito fixo com fluxo ascendente de ar. Os ensaios foram conduzidos até que as amostras alcançassem o equilíbrio na sua própria umidade e a umidade do ar de secagem. A cinética de secagem foi avaliada através dos Modelos Difusional, empírico exponencial de dois parâmetros e semi-empírico de Page, através desses modelos foram encontradas difusividades da ordem de 10-10 m/s². De maneira geral a difusividade aumentou com o tempo. As maiores taxas de secagem foram obtidas para a casca de banana Maçã, Prata e Pacovan respectivamente. A qualidade obtida do produto foi avaliada através das seguintes análises: atividade enzimática, minerais e atividade de água A condição de temperatura de secagem que gerou um produto final com melhor qualidade foi a de 60°C para as três variedades.
5

Bio-methane potential of exotic food waste and water hyacinth

Longjan, Gurumwal George January 2016 (has links)
Region specific foods in the Niger Delta like yam and cassava are consumed on a daily basis by at least 70% of the population. In addition to other commonly consumed foods, high volumes of unavoidable food wastes are generated. With 78% of the households in the region disposing their waste by burying, burning or in unauthorised heaps, environmental degradation is sustained. The region also suffers an infestation of Water Hyacinth (WH). Anaerobic Digestion (AD) presents a viable way of managing these wastes in addition to providing a clean source of energy. Limited research has been conducted on the characterisation and biogas potential of these exotic food wastes due to their localised availability, leading to a knowledge gap. My original contribution to knowledge is the Specific Waste Index (SWI), nutrient characterisation and biogas potential of the local food wastes and WH. Also novel is the design and optimisation of the AD process for mono and codigestion including the quarter hourly analysis of CH4 and CO2 content of the biogas composition over the complete duration of an AD test. The research approach was experimental and involved using conventional research methods in new fields of investigation. SWI was determined by replicating local food processing practices while nutrient composition was obtained using standard analytical methods. The Bio-Methane Potential (BMP) tests were carried out on the four most common food wastes, Yam Peel (YP), Cassava Peel (CP), Cocoyam Peel (CoP), Plantain Peel (PP), following VDI 4630 guidelines and using a newly designed cost-effective bioreactor. Laboratory scale batch reactors ran over 20 days at 37⁰C (310 K). The food wastes were anaerobically co-digested with WH in the ratio 2:1 g Volatile Solid (VS) with a total substrate mass of 8.4 g VS. The S:I ratio was 1:2 g VS and tests were carried out in duplicates to give an indication of repeatability. The results showed a wide range of SWI from 0.2-1.5. The Total Solid (TS) content varied from 7% for WH to 82% for Egusi Shell. Crude Protein and Crude Fibre were highest for Ugwu Stalk at 37% VS and Egusi Shell at 82% VS respectively. Cassava Peel had the highest oil content at 25% VS. NFE which was the major nutrient for 80% of the samples was highest for Yam Peel at 82% VS. YP+WH, CP+WH, CoP+WH and PP+WH had specific biogas yields of 0.42, 0.29, 0.39, and 0.38 m3/kg VS respectively. The yields represented 76%, 48%, 70% and 69% of their respective theoretical values. The samples had their highest methane content during the Technical Digestion Time (T80) period, which lasted up to the 8th day of digestion. The pH values ranged from 7.3 to 7.9 indicating that there was no inhibitory accumulation of organic acids. The results of the mono-digestion tests showed that co-digestion with WH reduced the biogas yields for YP, CP, CoP and PP by 16%, 22%, 7% and 7%. This drop in gas production was due to presence of complex molecules in the WH co-substrate, which cannot be digested by the anaerobic microbes. Further tests showed that fresh waste produced more biogas than dry samples, while a lower S:I produced more biogas due to increased microbial population. It was concluded that waste and nutrient content varied widely between different types of Niger Delta foods. In addition mesophilic digestion of food wastes have good biogas potentials which reduce when co-digested with water hyacinth. The methane content is shown to vary widely throughout an AD test. The findings of this research would provide valuable information to AD databases and its implementation would support clean energy production, environmental remediation and allow researchers in poor regions to perform BMP test on novel feedstock using cost-effective reactors. Key Words: Anaerobic Digestion, Co-Digestion, Water Hyacinth, Niger Delta, Yam, Cassava, Cocoyam, Food Waste, Specific Waste Index, Biogas.
6

Valor nutricional de partes convencionais e não convencionais de frutas e hortaliças

Monteiro, Betânia de Andrade [UNESP] 19 December 2008 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:24:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-12-19Bitstream added on 2014-06-13T20:12:52Z : No. of bitstreams: 1 monteiro_ba_me_botfca.pdf: 668024 bytes, checksum: f5ae74ef60bcd570fedd8ddca841f350 (MD5) / As informações sobre a composição de vegetais cultivados em solos brasileiros são escassas e mais ainda de partes não convencionais dos alimentos, como cascas, talos e folhas. O desconhecimento dos valores nutricionais dessas partes induz ao mau aproveitamento, ocasionando o desperdício de toneladas de recursos alimentares. Como incentivo ao melhor aproveitamento dos alimentos e como alternativa de dieta nutritiva e de baixo custo, foram verificados o rendimento e as composições de calorias, proteínas, carboidratos, lipídeos, fibras, vitamina C, ferro, cálcio, potássio e umidade em partes convencionais e não convencionais de frutas e hortaliças, amplamente consumidas pela população. Os vegetais foram adquiridos em estabelecimentos comerciais da cidade de Botucatu / SP. As análises foram realizadas em polpas, cascas, flores, folhas ou talos de abacaxi, abóbora, beterraba, brócolis, chuchu, couve, couve-flor, manga, mamão, pepino e salsa. Para comparação entre as médias dos resultados, foi utilizado o teste de Tukey ao nível de 5% de probabilidade, sendo os valores encontrados mais significativos para carboidratos em frutas, proteínas em folhas, lipídeos em pequenas quantidades para todas as partes analisadas, fibras em todas as partes não convencionais, vitamina C em mamão, brócolis e salsa, ferro em folhas e talos de beterraba, cálcio em todas as folhas principalmente a de couve-flor e potássio em cascas de mamão e talos de brócolis e salsa. No presente trabalho pode-se concluir que a utilização integral dos vegetais pode auxiliar no alcance das necessidades nutricionais e na melhora do estado de saúde e qualidade de vida dos indivíduos, principalmente com a ajuda de programas que divulguem essas informações através de receitas práticas para o dia a dia e orientações para uma alimentação mais saudável e econômica. / The information about the composition of fruit and vegetables cultivated in Brazilian soil is scarce, and more so in relation to their mostly non-utilized parts, such as skins, peels, stalks and leaves. The lack of knowledge about the nutritional value of these nutriments often leads to their non-utilization, which results in the waste of tons of food resources. In order to stimulate better utilization of food and offer an alternative of nutritive diet at low cost, the yield and the composition of calories, proteins, carbohydrates, lipids, fibres, vitamin C, iron, calcium, potassium and humidity, in both the utilized and non-utilized parts of those fruit and vegetables, which are mainly consumed by the population, were analyzed. The fruit and vegetables were purchased in shops of the city of Botucatu / SP. The analyses were carried out in pulps, skins, flowers, leaves or stalks of pineapple, pumpkin, beetroot, broccoli, chayote, cabbage, cauliflower, mango, papaya, cucumber and parsley. For comparison between the average of the results, the Tukey test, at 5% level of probability, was used and the results found are more significant in relation to carbohydrates in fruit, proteins in leaves, lipids in small quantities for all the parts analysed, fibres in all non-utilized parts, vitamin C in papaya, broccoli and parsley, iron in leaves and stalks of beetroot, calcium in all leaves and mainly in cauliflower leaves and potassium in skins of papaya and stalks of broccoli and parsley. The present study concludes that the integral utilization of fruit and vegetables can assist in obtaining necessary nutrients and improving the state of health and quality of life of individuals, especially with the support of programmes that publicise this information through recipes and guidance towards a more economic and healthy eating.
7

Cascas liofilizadas de manga Tommy Atkins: teor de fitoquímicos bioativos e potencial antioxidante

ARAÚJO, Cristiane Rodrigues de 31 July 2012 (has links)
Submitted by (edna.saturno@ufrpe.br) on 2016-07-26T12:47:23Z No. of bitstreams: 1 Cristiane Rodrigues de Araujo.pdf: 1357200 bytes, checksum: e679be2445ef965c1948578b245819fa (MD5) / Made available in DSpace on 2016-07-26T12:47:23Z (GMT). No. of bitstreams: 1 Cristiane Rodrigues de Araujo.pdf: 1357200 bytes, checksum: e679be2445ef965c1948578b245819fa (MD5) Previous issue date: 2012-07-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This work had as objective to characterize of freeze-dried bark of mango Tommy Atkins, come from organic farming, and defining the conditions of the polyphenols extraction process. The peels were crushed and the flour was submitted to the determination of proximate composition, minerals and bioactive phytochemicals and antioxidant potential employing techniques titrimetric, spectrophotometric and chromatographic. To define the optimal conditions of the process was applied the of factorial design 2² as independent variables: temperature 25-50° C and time stirring 30 to 90 min), and as response the total phenolics concentration in the extract. This experimental design was applied in the following process types: a) Extraction sequentially- hydroacetonic solution (80%), followed by hydromethanolic solution (80%); b) Extraction sequentially- hydromethanolic solution (80%), followed by hydroacetonic solution (80% ); c) Extraction non-sequential-hydroacetonic solution (80%) and d) extraction non-sequential- hydromethanolic solution (80%). The extracts were submitted to antioxidant assays, capture radicals in model system (DPPH, ABTS, ORAC) and antioxidant assays in lipid systems (coupled oxidation of β -carotene-linoleic acid, peroxidation of linoleic acid - ferric thiocyanate method, and accelerated storage test in an oven) and high performance liquid chromatography analyses for identification of polyphenols. The mango flour showed high levels of carbohydrates, potassium, sodium, calcium and phosphorus, total phenolics, ascorbic acid and β-carotene. The factorial design defined as the ideal sequential extraction (80% methanol, followed by 80% acetone) and the following process conditions: temperature 37.5°C and 25ºC; time stirring of 30 and 60 min, whose extracts showed, respectively, higher total phenolic content (2407.16μg. mL-1) (Ext-5), and increased sequestration capacity DPPH (95%) (Ext-7). Both extracts exhibited significant antioxidant capacity against free radicals ABTS, DPPH and ORAC, and in lipid system. The chromatographic analysis revealed the presence in both extracts of the phenolic acids (benzoic acid and cinnamic acid derivatives), flavonoids and a xanthone, but with quantitative and qualitative differences between the profiles of the extracts. Synaptic acid, syringic acid, taxofoline, isoquercetine and mangiferin were the major constituents of these extracts. Thus, considering the chemical composition and antioxidant capacity, the agro-industrial waste of Tommy Atkins mango emerges as a potential source of natural antioxidant. / Este trabalho teve como objetivo caracterizar cascas liofilizadas de manga Tommy Atkins, provenientes de um cultivo orgânico, quanto à composição centesimal, de minerais, de fitoquímicos bioativos, e o potencial antioxidante além de definir as condições ideais para obtenção de extratos com elevado teor de polifenóis. As cascas liofilizadas foram trituradas, e a farinha submetida às determinações analíticas empregando-se técnicas titulométricas, espectrofotométricas e cromatográficas. Para definição das condições ideais de processo (tempo de agitação; temperatura e tipo de processo) aplicou-se o planejamento fatorial 2² , tendo como variáveis independentes: temperatura de 25 a 50°C e tempo de agitação de 30 a 90 min; e como resposta o teor de fenólicos e a capacidade de sequestrar o radical DPPH. O planejamento foi aplicado aos seguintes tipos de processo: a) Extração sequencial-solução hidroacetônica (80%), seguida da solução hidrometanólica (80%); b) Extração sequencial-solução hidrometanólica (80%), seguida da solução hidroacetônica (80%); c) Extração não sequencial-solução hidroacetônica (80%); d) Extração não sequencial-solução hidrometanólica (80%). Os extratos obtidos utilizando as condições ideais foram submetidos aos ensaios antioxidantes, de captura de radicais, em sistema modelo (DPPH; ABTS; ORAC) e aos ensaios antioxidantes em sistemas lipídicos (oxidação acoplada do B-caroteno/ácido linoléico; da peroxidação do acido linoleico – método tiocianato férrico; e do teste acelerado em estufa), e a cromatografia liquida de alta eficiência (HPLC) para identificação dos polifenóis. A farinha de manga apresentou elevados teores de carboidratos, potássio, sódio, cálcio e fósforo, fenólicos totais, ácido ascórbico e β-caroteno. O planejamento fatorial definiu como ideal a extração sequencial (metanol 80%, seguido por acetona 80%) e as seguintes condições de processo: temperatura de 37,5ºC e 25ºC e tempo de extração de 30 e 60min; cujos extratos apresentaram, respectivamente, maior teor de fenólicos totais (2407,16μg. mL-1) (Ext-5), e maior capacidade de sequestro do radical DPPH (95%) (Ext-7). Os dois extratos exibiram expressiva capacidade antioxidante frente aos radicais livres ABTS, DPPH e ORAC; bem como em meio lipídico. A análise cromatográfica revelou a presença, nos dois extratos, de ácidos fenólicos (derivados do ácido benzóicos e cinâmicos), flavonóides e uma xantona, porém com diferenças quantitativas e qualitativas entre os perfis dos extratos. O ácido siríngico, ácido sináptico, a taxofolina, a isoquercetina e a mangiferina foram os constituintes majoritários nestes extratos. Assim, considerando a composição química e a ação antioxidante, o resíduo agroindustrial de manga Tommy Atkins surge como uma fonte potencial de antioxidante natural.
8

Estudo dos cianog?nicos em casca de maracuj? atrav?s de bioensaio e quantifica??o de amostras por processos t?rmicos diferentes

NASCIMENTO, Elisabete Maria da Gra?a Costa 26 February 2016 (has links)
Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-06-29T18:35:24Z No. of bitstreams: 1 2016 - Elisabete Maria da Gra?a Costa do Nascimento.pdf: 1991326 bytes, checksum: cc5f12994a8bca0da10c49a977a74e39 (MD5) / Made available in DSpace on 2017-06-29T18:35:24Z (GMT). No. of bitstreams: 1 2016 - Elisabete Maria da Gra?a Costa do Nascimento.pdf: 1991326 bytes, checksum: cc5f12994a8bca0da10c49a977a74e39 (MD5) Previous issue date: 2016-02-26 / CAPES / Brazil is the largest producer and consumer in the world passion fruit and their production is growing every year due to the good acceptance of its juice. Passion fruit juice is a small part of the fruit and the peels presents a problem for the environment, loss of material rich in fiber and loss than may pose as a gain for the economy. The aim of this study was to present a safe possibility for exploitation and processing of passion fruit peel. For this was done drying with application of ultrasound(SCUS) on the drying kinetics and also tested the antioxidant property and quantified the cyanogenic glycosides. Bioassay with Artemia salina was undertaken to determine and assess the lethal dose for 50% of the population of A. salina (LD50). The cyanogenic glycosides Amygdalin and prunasin in passion fruit peel flour sample sold in the Rio de Janeiro market were quantified in samples processed by Lyophilization (L), processed by convective drying (SC) and samples submitted to the thermoplastic extrusion process(ET). Major benefits have been found in the use of passion fruit peel as an ingredient as the decrease of glucose levels in blood and cholesterol, anti-inflammatory action and other. The dietary fiber content was quantified by various authors and ranged 35-90% and these findings have encouraged the development of several products, for example, breakfast cereal, diets cookie, sweet biscuits, pasta, cereal bars and candies in syrup added flour of the passion fruit peel, and others, but few studies consider the quantification of residual cyanogenic as an important part of the evaluation. The cyanotic toxicity of some plants has been well established by epidemiological studies and exposure to cyanogenicglycosides food, from acute or chronic form, can cause neuropathology, goiter, cretinism endemic and sometimes death. It was carried out as a strategy for studying processes in the best conditions to obtain security for toxic levels of cyanogenic and preservation of bioactive compounds in the tested processes. For quantification of Amygdalin glycosides and prunasin were used high-performance liquid chromatography. The tests to evaluate the antioxidant activity were made using the method for the reduction of iron (Ferric-Reducing Ability Power (FRAP)) and by the measure of total phenolic compounds against the Folin Ciocalteu reagent. The result of drying with ultrasound coupled at the lower temperatures tested affected the kinetic accelerating the process and preserved better antioxidant capacity. The microstructure also revealed that during the drying process wrinkling of matrix cells behave more evenly going in the same direction and drying without the use of ultrasound cells show a more disorganized wrinkling. The results for A. salina bioassay showed that the LD50 for potassium cyanide was 2.83 mg kg-1 and passion fruit peels in natura 397.30 mg kg-1. The results of the quantification Amygdalin and prunasin for passion fruit peels drying process showed that only the sample with ultrasound coupled drying at a temperature of 40?C and had only one commercial levels below Brazilian ANVISA standards. The general conclusion was that there are not enough studies to prove that the use of passion fruit peel flour is harmless to human health and that exposure to cyanogenic, even at low levels, can provide a public health problem in Brazil. / O Brasil ? o maior produtor e consumidor de maracuj? do mundo e sua produ??o vem crescendo a cada ano devido ? boa aceita??o do seu suco. O suco de maracuj? representa uma pequena parte do fruto e a casca dele apresenta um problema para o meio ambiente, perda de material rico em fibras e perda do que ele pode representar como ganho para economia do pa?s. O objetivo desse estudo foi apresentar uma possibilidade segura para aproveitamento e processamento da casca do maracuj?. Para isso foi feito uma secagem com aplica??o do ultrassom (SCUS) sobre cianog?nicos. Foi feito um bioensaio com Artemia salinapara determinar e avaliar a dose letal para 50% da popula??o de A. salina (DL50). Foram quantificados os glicos?deos cianog?nicos Amigdalina e Prunasina em amostra de farinha de cascas de maracuj? vendidos no mercado do Rio de Janeiro, em amostras processadas por liofiliza??o (L), processadas por secagem convectiva (SC) e amostras submetidas ao processo de extrus?o termopl?stica (ET). Grandes benef?cios t?m sido encontrados no uso da casca do maracuj? como ingrediente como a diminui??o dos n?veis de glicose no sangue e de colesterol, a??o anti-inflamat?ria e outras. O teor de fibra alimentar foi quantificado por v?rios autores e variaram de 35 a 90% e esses achados t?m incentivado o desenvolvimento de diversos produtos como, por exemplo, cereal matinal, cookie diets, biscoitos doces, massa aliment?cia, barra de cereais e doces em calda adicionados da farinha da casca de maracuj?, e outros, por?m poucos estudos consideram a quantifica??o dos cianog?nicos residuais como parte importante da avalia??o. A toxicidade cianog?nica de alguns vegetais j? foi bem estabelecida por estudos epidemiol?gicos e a exposi??o a alimentos que cont?m glicos?deos cianog?nicos de forma aguda ou cr?nica pode causar neuropatologias, b?cio, cretinismo end?mico e algumas vezes morte. Assim, foi realizado como estrat?gia para o estudo processamentosnas melhores condi??espara se obter a seguran?a quanto aos n?veis t?xicos de cianog?nicos e a preserva??o dos compostos bioativos nos processos testados.Para quantifica??o dos glicos?deos Amigdalina e Prunasina foi utilizada cromatografia liquida de alta efici?ncia. Os testes para avaliar a atividade antioxidante foram feitos atrav?s do m?todo pela redu??o do ferro (Ferric-Reducing Ability Power (FRAP)) e pela medida dos compostos fen?licos totais frente ao reagente Folin Ciocalteu. O resultado da secagem com ultrassom acoplado nas mais baixas temperaturas testadas afetou a cin?tica acelerando o processo e preservou melhor a capacidade antioxidante. A microestrutura revelou tamb?m que durante o processo de secagem o enrugamento das c?lulas da matriz se comportam mais uniformemente acontecendo na mesma dire??o e na secagem sem o uso do ultrassom as c?lulas mostram um enrugamento mais desorganizado. Os resultados para o bioensaio com A. salina mostraram que a DL50 para cianeto de pot?ssio foi de 2,83 mg kg-1e para cascas de maracuj? in natura de 397,30 mg kg-1. Os resultados da quantifica??o de Amigdalina e Prunasina para os processos de secagem de cascas de maracuj? mostraram que apenas a amostra com secagem com ultrassom acoplado na temperatura de 40?C e uma comercial tiveram n?veis abaixo dos padr?es brasileiros da ANVISA. A conclus?o geral foi que n?o existem estudos suficientes que comprovem que a utiliza??o da farinha de casca de maracuj? ? in?cua ? sa?de humana e que uma exposi??o aos cianog?nicos, mesmo que em baixos n?veis, pode oferecer um problema de sa?de p?blica para o Brasil.
9

Valor nutricional de partes convencionais e não convencionais de frutas e hortaliças /

Monteiro, Betânia de Andrade, 1980- January 2008 (has links)
Orientador: Rogério Lopes Vieites / Banca: Flávia Queiroga Aranha de Almeida / Banca: Magali Conceição Monteiro da Silva / Resumo: As informações sobre a composição de vegetais cultivados em solos brasileiros são escassas e mais ainda de partes não convencionais dos alimentos, como cascas, talos e folhas. O desconhecimento dos valores nutricionais dessas partes induz ao mau aproveitamento, ocasionando o desperdício de toneladas de recursos alimentares. Como incentivo ao melhor aproveitamento dos alimentos e como alternativa de dieta nutritiva e de baixo custo, foram verificados o rendimento e as composições de calorias, proteínas, carboidratos, lipídeos, fibras, vitamina C, ferro, cálcio, potássio e umidade em partes convencionais e não convencionais de frutas e hortaliças, amplamente consumidas pela população. Os vegetais foram adquiridos em estabelecimentos comerciais da cidade de Botucatu / SP. As análises foram realizadas em polpas, cascas, flores, folhas ou talos de abacaxi, abóbora, beterraba, brócolis, chuchu, couve, couve-flor, manga, mamão, pepino e salsa. Para comparação entre as médias dos resultados, foi utilizado o teste de Tukey ao nível de 5% de probabilidade, sendo os valores encontrados mais significativos para carboidratos em frutas, proteínas em folhas, lipídeos em pequenas quantidades para todas as partes analisadas, fibras em todas as partes não convencionais, vitamina C em mamão, brócolis e salsa, ferro em folhas e talos de beterraba, cálcio em todas as folhas principalmente a de couve-flor e potássio em cascas de mamão e talos de brócolis e salsa. No presente trabalho pode-se concluir que a utilização integral dos vegetais pode auxiliar no alcance das necessidades nutricionais e na melhora do estado de saúde e qualidade de vida dos indivíduos, principalmente com a ajuda de programas que divulguem essas informações através de receitas práticas para o dia a dia e orientações para uma alimentação mais saudável e econômica. / Abstract: The information about the composition of fruit and vegetables cultivated in Brazilian soil is scarce, and more so in relation to their mostly non-utilized parts, such as skins, peels, stalks and leaves. The lack of knowledge about the nutritional value of these nutriments often leads to their non-utilization, which results in the waste of tons of food resources. In order to stimulate better utilization of food and offer an alternative of nutritive diet at low cost, the yield and the composition of calories, proteins, carbohydrates, lipids, fibres, vitamin C, iron, calcium, potassium and humidity, in both the utilized and non-utilized parts of those fruit and vegetables, which are mainly consumed by the population, were analyzed. The fruit and vegetables were purchased in shops of the city of Botucatu / SP. The analyses were carried out in pulps, skins, flowers, leaves or stalks of pineapple, pumpkin, beetroot, broccoli, chayote, cabbage, cauliflower, mango, papaya, cucumber and parsley. For comparison between the average of the results, the Tukey test, at 5% level of probability, was used and the results found are more significant in relation to carbohydrates in fruit, proteins in leaves, lipids in small quantities for all the parts analysed, fibres in all non-utilized parts, vitamin C in papaya, broccoli and parsley, iron in leaves and stalks of beetroot, calcium in all leaves and mainly in cauliflower leaves and potassium in skins of papaya and stalks of broccoli and parsley. The present study concludes that the integral utilization of fruit and vegetables can assist in obtaining necessary nutrients and improving the state of health and quality of life of individuals, especially with the support of programmes that publicise this information through recipes and guidance towards a more economic and healthy eating. / Mestre
10

Valorisation fonctionnelle et antioxydante des épidermes de pommes Golden Delicious / Functional and antioxidant valorization of apple peels Golden Delicious

Duchêne-Massias, Audrey 20 May 2015 (has links)
Les pommes sont considérées comme bénéfiques pour la santé, de part leur teneur en polyphénols qui leur confèrent l’étiquette "d’aliment santé". Les procédés de transformation agroalimentaire des fruits et légumes génèrent des coproduits qui sont considérés comme sans valeur par les industriels. Or, au regard des volumes générés, ce sont des sources abondantes de nutriments.Une voie possible de valorisation de ces coproduits est la réintroduction dans des produits alimentaires en tant qu’ingrédient, de façon à proposer des aliments enrichis en molécules fonctionnelles. Pour ce faire, deux voies ont été explorées: l’utilisation de poudres d’épidermes de pommes pour stabiliser une émulsion et l’extraction des polyphénols au moyen de la technologie à base de CO2 supercritique. Ce travail examine également des solutions pour remédier au problème de brunissement enzymatique, comme le traitement thermique et l’addition de poudres de fruits naturellement riches en agents antibrunissement.Les phases de préparation des pommes sont de réelles étapes de transformation qu’il faut optimiser et maîtriser afin de préserver toutes les propriétés antioxydantes des coproduits végétaux. Nos travaux ont également permis de mettre en évidence des propriétés plus fonctionnelles des pelures de pommes, comme agent stabilisant d’émulsions. L’impact des paramètres d’extraction a été mis en évidence par l’exploration de plusieurs conditions telles que la masse chargée, le broyage, le protocole ainsi que la température et la composition du fluide extractant. / Apples are considered beneficial to health, because of their content of phenolic compounds that confer the label "health food". Fruits and vegetables food processes generate byproducts that are considered worthless by industrial. However, given the volumes generated, they are rich sources of nutrients.One possible way of valorization of these byproducts is the reintroduction of food as ingredient, to propose fortified foods with functional molecules. To do this, two approaches have been explored: the use of apple peels powders to stabilize an emulsion and the extraction of phenolic compounds by supercritical CO2+ethanol. This work also discusses solutions to remedy the enzymatic browning, such as heat treatment and the addition of naturally rich fruit powders as anti-browning agents.Apples preparation phases are real transformation steps which it’s necessary to optimize and master to preserve all the antioxidant properties of fruits and vegetables byproducts. Our works also highlight more functional properties of apple peels as a stabilizing emulsions agent. The impact of extraction parameters was demonstrated by the exploration of several conditions such as the loaded weight, the grinding, the protocol as well as the temperature and composition of supercritical fluids.

Page generated in 0.0387 seconds