Made available in DSpace on 2014-06-12T15:05:22Z (GMT). No. of bitstreams: 2 arquivo6660_1.pdf: 7184892 bytes, checksum: 8fae9bd630065f075daffb37c8672ff1 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2010 / O presente trabalho consiste na avaliação dos critérios e procedimentos analíticos adotados no estudo da faiança, uma categoria de material arqueológico freqüente e normalmente abundante nos sítios arqueológicos coloniais brasileiros, principalmente no Nordeste do Brasil. A escolha do tema se deve fundamentalmente à relação entre sua potencialidade enquanto documento material e o acesso objetivo às informações nele contidas. A subjetividade do processo analítico, no entanto, no que se refere à faiança, não permitiu, até o momento, um confiável acesso a esta documentação. Ao converter a faiança em documento legível, no entanto, o arqueólogo poderá recuperar informações importantes referentes ao conhecimento e domínio técnico de seus produtores, necessidades, relações comerciais e sociais de época, e perfil de seus consumidores. Vale salientar, no entanto, que apenas a faiança não será suficiente para explicar todas estas relações, mas poderá fornecer preciosas contribuições. Entretanto, a análise desta categoria de material não tem, até o momento, permitido uma leitura segura desta documentação, uma vez que não se dispõe de critérios analíticos adequados. A abordagem da faiança se baseia, normalmente, em critérios artísticos e não científicos. Conseqüentemente, a necessidade de avaliação e identificação de atributos objetivos que possam ser utilizados no processo de leitura desta categoria de documento é inquestionável. A faiança encontrada em escavações arqueológicas realizadas no Forte Orange, localizado na Ilha de Itamaracá-PE, nos anos de 2002 e 2003 constitui o objeto de estudo deste trabalho. Sua representatividade qualitativa e quantitativa transformou-a em excelente amostra para o estudo

Orientadores: Maria Regina Wolf Maciel, Patrícia Fazzio Martins Martinez / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-26T01:57:05Z (GMT). No. of bitstreams: 1 Medeiros_HeloisaHelenaBerredoReisde_D.pdf: 2926658 bytes, checksum: ecdad0019abf8c59be4ebbda4314ac06 (MD5) Previous issue date: 2014 / Resumo: O Brasil é o maior produtor mundial de laranjas, sendo também considerado um grande produtor e exportador mundial do óleo de laranja. Óleo de laranja doce, um importante subproduto gerado a partir da produção de suco de laranja, é constituído por aproximadamente 400 compostos, dentre os quais, destacam-se as classes de terpenos, oxigenados e flavonoides. Essas classes de compostos apresentam elevado potencial para as indústrias alimentícia, cosmética, farmacêutica e química. O fracionamento deste óleo tem recebido grande atenção da comunidade científica e industrial devido à instabilidade de determinados componentes. Neste trabalho, a separação e concentração dos componentes limoneno, valenceno, decanal, tangeritina e nobiletina foram realizadas utilizando-se um sistema híbrido de evaporação a pressões de 2 e 20 mbar. Três frações resultantes do sistema foram obtidas, são elas: destilado, lateral e resíduo. Através de um planejamento experimental do tipo composto central, observou-se que a temperatura do evaporador é a variável que tem maior influência nos resultados. As maiores concentrações de limoneno foram encontradas nas frações destilado e lateral, chegando-se à concentração de 99,5%. Os compostos valenceno e decanal não foram identificados na fração destilado e suas maiores concentrações estão presentes na fração resíduo. Comportamento semelhante foi observado para os flavonoides tangeritina e nobiletina, os quais foram concentrados na fração resíduo. De acordo com os resultados obtidos neste trabalho, é promissor separar e concentrar os compostos citados acima presentes no óleo de laranja doce utilizando um sistema híbrido de evaporação / Abstract: Brazil is the world¿s largest orange producer, and is also considered a major producer and exporter of orange oil. Sweet orange oil, an important by-product generated from the production of orange juice, consists of approximately 400 compounds, among which stand out the classes of terpenes, oxygenated and flavonoids. These classes of compounds have high potential for the food, cosmetic, pharmaceutical and chemical industries. Fractionation of this oil has received great attention of the scientific and industrial community due to the intability of certain components. In this work, the separation and concentration of the components limonene, valencene, decanal, tangeritin and nobiletin were performed using a hybrid system of evaporation at pressures from 2 and 20 mbar. Three fractions of the resulting system were obtained, they are: distillate, side and residue. Through an experimental design of the central composite type, it is observed that the evaporator temperature is the variable that has the greatest influence on the results. The highest concentrations of limonene were found in the distillate and side fractions, reaching to the concentration of 99.5%. The valencene and decanal compounds were not identified in the distillate fraction and its highest concentrations are present in the residue fraction. Similar behavior eas observed for tangeritin and nobiletin flavonoids, which are concentrated in the residue fraction. According to the results obtained in this study it is promising to separate and concentrate the compounds mentioned above present in sweet orange oil using a hybrid system of evaporation / Doutorado / Desenvolvimento de Processos Químicos / Doutora em Engenharia Quimica

Orientador: Gabriela Alves Macedo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-20T21:21:56Z (GMT). No. of bitstreams: 1 Ferreira_LiviaRosas_M.pdf: 6389418 bytes, checksum: 474ea71f0f4b85a4fb59fa346c31f972 (MD5) Previous issue date: 2012 / Resumo: A tanino acil hidrolase (EC 3.1.1.20), conhecida como tanase, é uma enzima com habilidade de atuar em ligações éster e depsídicas de taninos hidrolisáveis e também foi descrita como capaz de hidrolisar polifenóis como ácido clorogênico, epicatequina galato e epigalocatequina galato. Os polifenóis, ou compostos fenólicos, estão distribuídos em uma ampla variedade de fontes vegetais e estão relacionados à prevenção de câncer e doenças cardiovasculares. No entanto, os polifenóis ocorrem frequentemente como glicosídeos ou outros conjugados, o que pode comprometer a biodisponibilidade e os efeitos benéficos destes compostos à saúde, sendo necessária a biotransformação destes conjugados no trato gastrointestinal. Como alternativa tecnológica, a biotransformação enzimática dos polifenóis ou de suas fontes vegetais também pode liberar estes compostos de seus conjugados e consequentemente, melhorar a atividade funcional de tais antioxidantes. O objetivo do presente trabalho foi estudar a especificidade do extrato semipurificado de tanase de Paecilomyces variotii frente a diferentes padrões comerciais de polifenóis e avaliar sua atuação na matriz alimentar suco de laranja quanto a modificações em características físico-químicas, perfil fenólico e atividade antioxidante. O estudo da especificidade do extrato semipurificado de tanase foi realizado por CLAE-DAD e ESI-MS e o suco de laranja foi avaliado quanto aos parâmetros acidez total titulável, sólidos totais, pH, teor de vitamina C e fenólicos totais. As alterações no perfil fenólico do suco de laranja foram avaliadas por CLAE-DAD e a atividade antioxidante pelos métodos in vitro ORAC e de sequestro de radicais DPPH. Os resultados obtidos por CLAE-DAD e ESI-MS mostraram que não houve hidrólise dos padrões ácido clorogênico, ácido ferúlico, ácido elágico, resveratrol, quercetina e hesperetina pelo extrato semipurificado de tanase nas condições empregadas para o teste. No entanto, foi observado a hidrólise da ligação entre a aglicona e o dissacarídeo dos flavonoides rutina, naringina e hesperidina, gerando respectivamente os produtos quercetina, naringenina e hesperetina, e indicando uma atividade diglicosídica do extrato semipurificado de tanase. Para o suco de laranja, os resultados de acidez titulável, pH, sólidos solúveis e vitamina C não apresentaram diferença significativa após o tratamento enzimático do suco com extrato semipurificado de tanase, no entanto, houve um aumento de 16,8% no teor de fenólicos totais. Além disso, foi verificada uma modificação no perfil polifenólico do suco de laranja obtido por CLAE-DAD, resultando em um aumento na atividade antioxidante do suco biotransformado em aproximadamente 50% pelo método ORAC e 70% pelo método DPPH. Os padrões comerciais hesperidina e naringina biotransformados pelo extrato semipurificado de tanase também apresentaram maior atividade antioxidante do que o controle sem reação. Pelo que se tem conhecimento, a hidrólise de flavonoides glicosilados por tanase é um relato inédito na literatura e, portanto este trabalho fornece novos substratos para o extrato semipurificado de tanase de P. variotii e confirma que a biotransformação é uma boa estratégia para melhorar a atividade antioxidante in vitro de polifenóis e de suco de laranja / Abstract: Tannin acyl hydrolases (EC 3.1.1.20), commonly named as tannases, are enzymes able to act on ester and depside bonds of hydrolysable tannins and have also been described to hydrolyse polyphenols such as chlorogenic acid, epicatechin gallate and epigallocatechin gallate. Polyphenols, or phenolic compounds, are widely distributed in the plant kingdom and are related to the prevention of cancer and cardiovascular diseases. However, polyphenols are often found as glycosides or other conjugates, which may affect their bioavailability and health benefits, being necessary the biotransformation of these compounds in the gastrointestinal tract. As a technological alternative, the enzymatic biotransformation of the polyphenols or their plant sources can also release these compounds from their conjugates and therefore improve the functional activity of these antioxidants. The objectives of the present study were to investigate the specificity of the crude extract of tannase from Paecilomyces variotii in reaction with differents comercial standards of phenolic compounds and to evaluate the effects on the physico-chemical properties, phenolic profile and antioxidant activity of the orange juice reacted with the crude extract of tannase. The specificity study of the crude extract of tannase was performed by HPLC-DAD and ESI-MS. The orange juice was subject to analysis of titratable acidity, pH, and total solids, vitamin C and total phenolics contents. Furthermore, changes in the phenolic profile of orange juice were analyzed by HPLC-DAD and the antioxidant capacity of the samples was tested by in vitro DPPH and ORAC assays. The results obtained by HPLC-DAD and ESI-MS did not show hydrolysis of the standards chlorogenic acid, ferulic acid, ellagic acid, resveratrol, quercetin and hesperetin at test conditions. However, the crude extract of tannase was able to hydrolyse the glucosidic bond between disaccharide and aglycone of the flavonoids rutin, hesperidin and naringin, yielding as products quercetin, hesperetin and naringenin, respectively, and indicating a diglycosidase activity of the crude extract of tannase. For orange juice, the results of acidity, pH, soluble solids and vitamin C showed no significant difference after enzymatic treatment with the crude extract of tannase, but there was an increase of 16.8% in total phenolic content. In addition, there was an extensive modification in the polyphenolic profile from the biotransformed orange juice obtained by HPLC-DAD, which resulted about 50% and 70% increase in orange juice antioxidant activity by ORAC and DPPH methods, respectively. The standards hesperidin and naringin biotransformed by crude extract of tannase also showed higher antioxidant activities than the control. To the best of our known, this is the first report about tannase which could hydrolyze flavonoid glycosides and, therefore this work provides new substrates for crude extract of tannase from P. variotii and confirms that biotransformation is a good strategy to improve in vitro antioxidant activity of polyphenols and orange juice / Mestrado / Ciência de Alimentos / Mestra em Ciência de Alimentos

Orientador: Pilar Rodriguez de Massaguer / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-04T02:27:14Z (GMT). No. of bitstreams: 1 TamegaJunior_WilsonPedro_M.pdf: 3655390 bytes, checksum: 7393715ee9c1c652503290358f0b2729 (MD5) Previous issue date: 2005 / Mestrado / Ciência de Alimentos / Mestre em Ciência de Alimentos

Orientador: Roberto Herminio Moretti / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-04T02:32:16Z (GMT). No. of bitstreams: 1 BenassiJunior_Mario_D.pdf: 1676376 bytes, checksum: f60c2e75a305891a4245bfd284c43500 (MD5) Previous issue date: 2005 / Resumo: Foram formuladas três tipos de bebidas cítricas: Refrigerante, Refresco e Energético, e avaliada a influência do nível de maturação do suco na qualidade final dessas formulações. O Refrigerante foi formulado com 10 % de suco, em 5 diferentes níveis de maturação, com relação Brix/Acidez (¿Ratio¿) de: 8, 10, 12, 14 e 17. Os Refrescos foram formulados com 30 % de suco, oriundo de níveis de ¿Ratio¿ 10 e 17, e com três diferentes níveis de acidez (ácido cítrico): 0,75%, 0.55%, 0,35%, gerando bebidas com níveis finais de ¿Ratio¿ de 14, 19 e 30, totalizando seis tratamentos. Os Energéticos foram formulados com 2 % de suco, em níveis de ¿Ratio¿ de 10 e 17, e três níveis de estabilizante (goma xanthana) 0,04%, 0,05% e 0,06%, totalizando seis tratamentos. Nessas bebidas, e no suco concentrado utilizado como matéria prima, foram realizadas as seguintes determinações físico-químicas: viscosidade, cor (Hunter -L, a, b), opacidade, ácido ascórbico, pH, pectina, prolina, atividade de pectinesterase, cinzas, e minerais (N, P, K, Ca, Mg, S, B, Cu, Fe, Mn, Zn, Na, Al), em triplicata, além disso as bebidas foram avaliadas através de análise sensorial, composta de um teste de aceitação, com escala não estruturada de 0 a 9 (desgostei muitíssimo, gostei muitíssimo), para os atributos: aroma, acidez, sabor, doçura, viscosidade e impressão global. Tanto as análises físicvo-químicas como a sensorial foram realizadas no momento da produção para todas as bebidas, após 180 dias nos Refrigerantes, e após 120 dias nos Energéticos e Refrescos. O Refrigerante não foi influenciado pelo nível de maturação do suco, apresentando menores: viscosidade, opacidade e teor de pectina, e maiores: pH, teor de ferro e cor, dentre as bebidas, sendo a bebida com a melhor avaliação sensorial. O Refresco foi influenciado pelo nível de maturação do suco na formulação, onde os Refrescos formulados com suco de ¿Ratio¿ 10, apresentaram a menor viscosidade, a maior opacidade e o maior teor de ácido ascórbico, enquanto que os Refrescos formulados com suco de ¿Ratio¿ 17 apresentaram cor mais clara e alaranjada, e maiores teores de prolina, cinzas e minerais, mas a pior avaliação sensorial dentre as bebidas. O Energético (2% de suco) também sofreu influência da maturação com os energéticos formulados com suco de ¿Ratio¿ 10, apresentando maiores: opacidade e teor de ácido ascórbico e os Energéticos formulados com ¿Ratio¿ 17, maior teor de cinzas, sendo esses as bebidas com a maior viscosidade, menor teor de minerais, e avaliação sensorial intermediária entre Refrigerantes e Refrescos / Abstract: Three different citrus juice drinks have been prepared: a soft drink (10 % of juice), an ade (30% of juice) and a sherbet (2 % of juice), all this beverages have been evaluated considering the influence provided by the maturation level of the juice used in the formulation. The soft drink has been formulated with 10 % of orange juice in five different levels of Brix/acid ratio of 8, 10, 12, 14 and 17. The orange ades have been formulated with 30 % of orange juice in two leves of brix/acid ratio: 10 and 17, and three different levels of acidity (citric acid): 0.75%, 0.55% and 0.25%, producing beverages with final brix/acid ratio of 14, 19 and 30. The sherbets have been formulated with 2 % of orange juice with two levels of brix/acid ratio 10 and 17, and three levels of texturizers (Xanthan gum): 0.04%, 0.05% and 0.06%. All this beverages, have been submitted to the folowing physicochemical determinations: viscosity, color (Hunter L, a, b), opacity, ascorbic acid, pH, total pectin, proline, pectin esterase activity, ashes and mineral content (N, P, K, Ca, Mg, S, B, Cu, Fe, Mn, Zn, Na, Al), realized in three repetitions. Besides that, a sensory evaluation was carried out in a acceptance test with a non-structured category scale form 0 to 9 (dislike extremely, like extremely), considering the following atributtes: flavor, acidity, taste, sweetness, viscosity and global impression. Each one of this evaluations have been realized just after the processing of the beverege and 180 days after it for the soft drink and 120 days after, for both orange ade and sherbet. The soft drink had been not affected by the maturation level of the juice, instead of it showed the lowest level of viscosity, opacity, pectin, and the highest levels of pH, Iron content and color, considering all the three beverages, and still has been achieved the best sensory evaluation among the beverages. The orange ade, however has been influenced by the maturation level of the orange juice, with the ones formulated in a brix/acid ratio of 10, achieving the lowest viscosity, but the higest opacity and ascorbic acid content, while the orange ades formulated with the orange juice in a brix/acid ratio of 17, achieveing more orange and bright color and the higest: prolin, ash and mineral content, on the other hand, showing the worst sensory evaluation among the beverges. The sherbet has been influenced by the maturation level, with the ones formulated with orange juice in a brix/acid ratio of 10, achieving highest opacity and ascorbic acid and the sherbets formulated with orange juice in a brix/acid ratio of 17, presenting the highest ash content. Therefore, these sherbets reached out the highest viscosity among the beverages and have been evaluated to an intermediate position between the soft drink and the orange ade, considering the sensory test / Doutorado / Tecnologia de Alimentos / Doutor em Tecnologia de Alimentos

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.

>Magister Scientiae - MSc / Clay diagenesis phenomenon and their effects on some petrophysical properties of lower cretaceous silliciclastic sandstones, offshore Orange basin have been established. Previous studies on Orange basin revealed that chlorite and quartz cements have significantly compromised the reservoir quality in this basin but it is expected that the reservoirs shows better improvement basinward, an analogy of this is displayed by tertiary sandstones deposit, offshore Angola. The main goal of this thesis is to perform reservoir quality evaluation by intergrating geological, geochemical and geophysical tools to substantiate the effects of clay minerals distribution and its subsequent diagenesis on the intrinsic properties (porosity, permeability and saturation) of reservoir intervals encountered within three wells in block 3A (deeper waters), offshore Orange basin. Five lithofacies were identified based on detailed core description from wells KF-1, KH-1 and AU-1 in this block. The facies were grouped based on colour and grain sizes, they are named : A1 (shale), A2 (sandstone), A3 (siltstone), A4 (dark coloured sandstone) and A5 (conglomerates).Depositional environment is predominantly marine, specifically, marine delta front detached bars and deepwater turbiditic sandstone deposit. Geophysical wire line logs of gamma ray, resistivity logs combo and porosity logs were interpreted, parameters and properties such as VCL, porosity, permeability and saturation were estimated from these logs and the values obtained were compared with values from conventional core analysis data, the values agreed well with each other. Detailed petrographic studies (SEM, XRD and thinsection) plus geochemical studies (CEC, EDS, pH, Ec) were carried out on twenty two core samples to establish if these clay minerals and other cements have pervasive effects on the reservoir quality or otherwise.

>Magister Scientiae - MSc / The evaluation of petroleum reservoirs has shifted from single approach to an integrated approach. The integration, analysis and understanding of all available data from the well bore and creating property models is an exceptional way to characterize a reservoir. Formulating, implementing, and demonstrating the applicability of the joint inversion of seismic and well-bore related observations, and the use of information about the relationship between porosity and permeability as the key parameters for identifying the rock types and reservoir characterization is a vital approach in this study. Correlating well and seismic data, potential reservoirs can be delineated and important horizons (markers) can be pointed out to better characterize the reservoir. This thesis aims to evaluate the potential petroleum reservoirs of the Wells K-A1, K-A2, K-A3 and K-H1 of the Shungu Shungu field in the Orange Basin through the integration and comparison of results from core analysis, wireline logs and seismic and attempt to produce a good reservoir model and by additionally utilizing Petrophysics and seismic and trying to better understand why the area has dry wells. Different rock types that comprise reservoir and non reservoirs are identified in the study and five Facie types are distinguished. Tight, fine grained sandstones with low porosity values ranging from 3% - 6% where dominant in the targeted sandstone layers. Porosity values ranging from 11% - 18% where identified in the massive sandstone lithologies which where hosted by Well’s K-A2 and K-A3. Low permeability values reaching 0.1mD exist throughout the study area. Areas with high porosity also host high water saturation values ranging from 70 – 84%. An improvement in the porosity values at deeper zones (3700m -3725m) and is apparent. Poroperm plots exhibit quartz cemented sandstones and density with neutron plot suggest that the sandstones in the area contain quarts and dolomite mineralization.Well K-A3, consist of a cluster by quartzitic sandstone, meaning there is a large amount of sandstone present. There are apparent high porosity values around the sandstone. What is apparent from this plot is that there are many clusters that are scattered outside the chart. This could suggest some gas expulsions within this Well. Sandstones within the 14B2t1 to 14At1 interval are less developed in the vicinity covered by well K-A2 than at the K-A1 well location. The main targeted sandstones belong to the lower cretaceous and lie just below 13At1. The four wells drilled in this area are dry wells. The areas/blocks surrounding this area have shown to possess encouraging gas shows and a comparative study could reveal better answers. At deeper zones of the well at an interval of 5350m -5750m, there are more developed sandstones with good porosity values. The volume of shale is low and so is the water saturation. The main target sandstones in the study area are the Lower Cretaceous sandstones which are at an interval 13At1. These sandstones are not well developed but from the property model of the target surface it can be seen that the porosity values are much more improved than the average values applied on all the zones on the 3D grid.

Vitamin A deficiency has been recognised as a widespread problem affecting about 750 million people, mostly in developing countries. Mortality due to vitamin A deficiency can be reduced by as much as 23% with improved vitamin A status. Vitamin A's immuneenhancing aspects strengthen the body's defence system against infectious diseases such as measles, malaria and diarrhoea, thus preventing death. Children beyond the weaning age (6 months to 6 years) are most at risk. In South Africa, one in three children has a low vitamin A status, with the rural areas being most affected. Orange-fleshed sweet potato (OFSP) has emerged as a promising plant source with a high beta-carotene content that can make a significant contribution to the vitamin A intake of individuals at risk of vitamin A deficiency. The purpose of this study was to determine the nutrient and sensory quality of OFSP. To this end, the nutrient content of different cultivars of OFSP was determined as well as the sensory characteristics and consumer acceptability was established. During the first phase, four different cultivars of OFSP i.e. Resisto, W119, Jewel and A 15, plus one composite sample, all cultivated by the Agricultural Research Council (ARC)-Roodeplaat, South Africa, were sampled for nutrient analysis. During the second phase (descriptive sensory analysis), four OFSP cultivars and one white-fleshed sweet potato (WFSP) cultivar i.e. Blesbok, were evaluated. A trained sensory panel was used to establish terminology for describing the sensory attributes of the different sweet potato cultivars in terms of its aroma, texture, flavour and aftertaste attributes. Consumer preference (n=180) for OFSP and WFSP was measured by means of a paired preference test. Focus group discussions were conducted to verify findings of the consumer preference test. The results obtained from the nutrient analysis confirmed that OFSP is an excellent source of beta-carotene. A 100 g portion of cooked OFSP can provide up to 6528 ~g beta-carotene, which is approximately 136% of the RDA for vitamin A for children four to eight years. High levels of other nutrients present in OFSP were identified namely vitamin C, calcium and zinc. OFSP further contributes 28% vitamin C, 13% calcium, 15% magnesium and 75.6% zinc of their daily requirements. This study confirms the valuable contribution that OFSP can make as a food-based approach to reduce vitamin A deficiency in individuals at risk. The sensory profiles indicated that OFSP differed from WFSP in colour, flavour and texture. OFSP is generally less moist and subsequently more dense and adhesive compared to WFSP. The latter being more fibrous and less firm than OFSP. Overall OFSP had and earthy aroma which was not typical of WFSP and had a sweeter flavour. The flavour of OFSP was described as similar to that of yellow vegetables such as butternut and pumpkin. Although the different OFSP cultivars had similar characteristics, differences were found in the moist, adhesive and grainy texture attributes as well as the vegetable sweet flavour. Resisto had the sweetest in flavour, with the most dense and pasty texture of the four OFSP cultivars. W119 had the grainiest texture. No significant differences were found in the earthy aroma, sweet potato and yellow vegetable flavour attributes. It can be concluded that in flavour, few differences were found among the OFSP, except in sweetness. OFSP differed primarily from each other in texture. The consumer preference test results showed that overall 85% of respondents preferred the taste of OFSP to that of WFSP, 53% liked the orange colour a lot while 24% liked the colour a little and the remaining 22 % disliked the colour (either a lot, a little, neither like nor dislike). The majority of the consumers (86%) indicated a willingness to buy OFSP. From these results it can be concluded that the taste and colour of OFSP are acceptable to consumers of sweet potato and that it has potential to be successful in the marketplace. Given the high level of consumer acceptability of OFSP, an opportunity exists to address vitamin A deficiency through commercially viable decentralised vine production centres. Such centres could be managed by commercial-, small-scale- and subsistence farmers in South Africa in key sweet potato production areas, with adequate water supply throughout the year. However, availability of commercially produced OFSP in retail sores in recent months, may change this prospect. / Dissertation (MConsSci)--University of Pretoria, 2008. / Consumer Science / unrestricted

The purpose of the present study is to determine the ascorbic acid values of orange marmalades made with and without commercial pectin; and to compare these values with those obtained by testing random samples of home and commercial prepared orange marmalades.