No description available.

Master of Science / Department of Food Science / Weiqun Wang / We previously selected a purple-fleshed sweetpotato p40 clone that has been shown to protect against colorectal cancer in a murine model. This study is to identify anthocyanins by using HPLC/MS-MS and assess the stability during various coking conditions. P40 possesses a high content of anthocyanins up to 13 mg/g dry matter. Total 12 acylated anthocyanins with caffeic, ferulic, and p-hydrobenzoic acid have been identified on either cyanidin or peonidin bases. The top three major anthocyanins are cyanidin 3-caffeoyl-p-hydroxybenzoyl sophoroside-5-glucoside, peonidin 3-caffeoyl sophoroside-5-glucoside, and cyanidin 3-(6'' -caffeoyl-6''-feruloylsophoroside)-5-glucoside, which account for an half of the total anthocyanin contents. Seven non-, mono-, or di-acylated cyanidin species and five mono- or di-acylated peonidin species contribute for 69% and 31% of total anthocyanins, respectively. Over 80% of total anthocyanins measured by acid hydrolysis were cyanidin derivatives. Therefore, as a cyanidin-predominated variety, p40 is unique when compared with other reported purple-fleshed sweetpotatoes that usually contain more peonidin than cyanidin. While baking does not impact overall contents of anthocyanins, steaming, high pressure cooking, microwaving, and frying significantly reduce 20% of total anthocyanin contents. Mono-acylated anthocyanins show a higher resistance against heat than di- and non-acylated. Among of which, cyaniding 3-p-hydroxybenzoylsophoroside-5-glucoside exhibits the best thermal stability. Better understanding of dietary anthocyanins and their stabilities may lead to the development of a functional anthocyanin-enriched sweetpotato product for health benefits.

Orientador: Mieko Kimura / Banca: Cristiane Hess de Azevedo Meleiro / Banca: José Antonio Gomes Vieira / Resumo: No presente trabalho, a retenção de a-caroteno e ß-caroteno de fatias de abóbora, submetidas ao processo de secagem foi avaliada, verificando o efeito do branqueamento (98°C/2 min), pré-tratamento osmótico com solução de sacarose (40%) e da temperatura de secagem (60°C, 70°C e 80°C). Secagem direta sem pré-tratamento acarretou perdas consideráveis de a-caroteno e ß-caroteno (17% - 18% e 11% - 13%, respectivamente), todavia, diferenças na retenção desses carotenóides devido à diferença de temperatura não foram observadas. a-Caroteno e ß-caroteno permaneceram estáveis durante o branqueamento. A desidratação osmótica provocou perda de aproximadamente 5% dos dois carotenóides. No entanto, o branqueamento e tratamento osmótico realizados previamente à secagem melhoraram a retenção de a-caroteno e ß-caroteno durante a secagem, exceto para a temperatura de 80°C na qual a amostra branqueada apresentou menor retenção. Devido à grande presença de mandioca e batata doce na alimentação básica de muitos países em desenvolvimento e sua importância como fonte de vitamina A principalmente das populações mais carentes, a retenção de ß-caroteno durante o cozimento, fritura e secagem foi avaliada utilizando amostras pareadas analisadas por CLAE. A retenção do ß-caroteno variou (2 ensaios) de 87% a 88% na batata doce cozida por 20 minutos. Como esperado a retenção das amostras fritas (67% - 68%) foi menor do que nas amostras cozidas devido à temperatura mais alta utilizada nessa forma de preparo. A mandioca apresentou menor retenção de ß-caroteno em ambos os processos quando comparado à batata doce. A porcentagem de retenção foi de 79% - 82% para amostras cozidas e 54% - 56% para as fritas. / Abstract: In this work, during the drying, the a-carotene e ß-carotene retention in sliced squash was evaluated, verifying the effect of blanching (98°C/2 min), osmotic pretreatment with sucrose solution (40%) and drying temperature (60°C, 70°C e 80°C). Drying without pre-treatment caused considerable losses of a-carotene e ß-carotene (17% - 18% e 11% - 13%, respectively), however, variances in carotenoid's retention due to different temperature were not observed. During blanching, a-Carotene e ß-carotene remained stable. Osmotic dehydration caused, in both carotenoids, an approximate loss of 5%. Even so, blanching and osmotic treatment done previously to drying improved the a-carotene e ß-carotene retention during the process, except at 80°C where the blanched sample showed lower retention. Cassava and sweetpotato are staple foods in many developing countries and an important vitamin A source, principally among the poorer population. Because of this, ß-carotene retention during cooking, frying and drying were evaluated using paired samples analyzed by HPLC. The retention of ß-carotene varied (2 trials) from 87% to 88 % in sweetpotatoes cooked for 20 minutes. As expected, the retention of fried samples (66% - 67%) was lower than boiled samples due the higher temperature of this preparation. Cassava presented lower retention of ß-carotene in both processes when compared to sweetpotato. The retention percentage was 78-81 for boiled and 54-56 for fried samples. / Mestre

Field and laboratory investigations were conducted in Burkina Faso to diagnose the causes of severe outbreaks of Bemisia tabaci populations and gênerai failures of chemical control against this pest in cotton. / Field and laboratory investigations were conducted in Burkina Faso to diagnose the causes of severe outbreaks of Bemisia tabaci populations and general failures of chemical control against this pest in cotton. The research efforts were oriented in the following three areas: I) the susceptibility of B. tabaci populations and its parasitoids to cotton insecticides; I) the susceptibility of B. tabaci populations and its parasitoids to cotton insecticides, a) conventional insecticides, b) novel insecticides; II) the relative abundance of B. tabaci and its parasitoids in the field; III) the biological activities of some botanical extracts as alternative insecticides against the pest.

Made available in DSpace on 2014-06-11T19:23:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-06-28Bitstream added on 2014-06-13T20:50:20Z : No. of bitstreams: 1 nascimento_p_me_sjrp.pdf: 638214 bytes, checksum: 4eb47d15aae570acb62a345e27cda325 (MD5) / Harvest Plus / No presente trabalho, a retenção de a-caroteno e ß-caroteno de fatias de abóbora, submetidas ao processo de secagem foi avaliada, verificando o efeito do branqueamento (98°C/2 min), pré-tratamento osmótico com solução de sacarose (40%) e da temperatura de secagem (60°C, 70°C e 80°C). Secagem direta sem pré-tratamento acarretou perdas consideráveis de a-caroteno e ß-caroteno (17% - 18% e 11% - 13%, respectivamente), todavia, diferenças na retenção desses carotenóides devido à diferença de temperatura não foram observadas. a-Caroteno e ß-caroteno permaneceram estáveis durante o branqueamento. A desidratação osmótica provocou perda de aproximadamente 5% dos dois carotenóides. No entanto, o branqueamento e tratamento osmótico realizados previamente à secagem melhoraram a retenção de a-caroteno e ß-caroteno durante a secagem, exceto para a temperatura de 80°C na qual a amostra branqueada apresentou menor retenção. Devido à grande presença de mandioca e batata doce na alimentação básica de muitos países em desenvolvimento e sua importância como fonte de vitamina A principalmente das populações mais carentes, a retenção de ß-caroteno durante o cozimento, fritura e secagem foi avaliada utilizando amostras pareadas analisadas por CLAE. A retenção do ß-caroteno variou (2 ensaios) de 87% a 88% na batata doce cozida por 20 minutos. Como esperado a retenção das amostras fritas (67% - 68%) foi menor do que nas amostras cozidas devido à temperatura mais alta utilizada nessa forma de preparo. A mandioca apresentou menor retenção de ß-caroteno em ambos os processos quando comparado à batata doce. A porcentagem de retenção foi de 79% - 82% para amostras cozidas e 54% - 56% para as fritas. / In this work, during the drying, the a-carotene e ß-carotene retention in sliced squash was evaluated, verifying the effect of blanching (98°C/2 min), osmotic pretreatment with sucrose solution (40%) and drying temperature (60°C, 70°C e 80°C). Drying without pre-treatment caused considerable losses of a-carotene e ß-carotene (17% - 18% e 11% - 13%, respectively), however, variances in carotenoid's retention due to different temperature were not observed. During blanching, a-Carotene e ß-carotene remained stable. Osmotic dehydration caused, in both carotenoids, an approximate loss of 5%. Even so, blanching and osmotic treatment done previously to drying improved the a-carotene e ß-carotene retention during the process, except at 80°C where the blanched sample showed lower retention. Cassava and sweetpotato are staple foods in many developing countries and an important vitamin A source, principally among the poorer population. Because of this, ß-carotene retention during cooking, frying and drying were evaluated using paired samples analyzed by HPLC. The retention of ß-carotene varied (2 trials) from 87% to 88 % in sweetpotatoes cooked for 20 minutes. As expected, the retention of fried samples (66% - 67%) was lower than boiled samples due the higher temperature of this preparation. Cassava presented lower retention of ß-carotene in both processes when compared to sweetpotato. The retention percentage was 78-81 for boiled and 54-56 for fried samples.

A dissertation submitted in partial compliance with the requirements for the Masters Degree in technology: Homoeopathy, Technikon Natal, 1999. / The most common and difficult insect to control in the greenhouse is the whitefly. Sweetpotato whitefly (Bemisia tabaci Genn.) was the species of whitefly selected to be investigated in this trial. Sweetpotato whitefly is a major pest on a variety of plants, ranging from ornamental flowers to agricultural crops such as tomato and cotton, resulting in important financial losses. Effective control options of sweetpotato whitefly are limited. / M

No description available.

Diploma Thesis concerns with usage of entomopathogenic fungi in system of biological control against greenhouse whitefly Trialeurodoes vaporariorum and sweetpotato whitefly Bemisia tabaci. The Aim of diploma thesis was through in vivo and in vitro experiments determinated the basic evolutional and vegetative characteristics of selected entomopathogenic fungi and compare their effectivity in completed system {\clqq}plant - pest - pathogenic``. All experiments and results are demonstrated in the tables and the graphs. The photo-documentation of the method used during founding and interpretation of experiments is the part of the thesis.

Sweetpotato (Ipomoea batatas) is a major staple food in Africa and the rest of the world where they are discovered to be a good source of carbohydrates, vitamin A, vitamin C and protein. The maximum production potential of the crop is being hampered by severe drought which ravages most parts of Africa. The main aim of this project therefore is to screen collected accessions of sweetpotatofor drought tolerance in a quick screening method with a view to identify cultivars that can perform well under water stress conditions. Fifty selected sweetpotato accessions consisting of cultivars and breeding lines collected from the ARC-VOPI gene bank were planted for drought screening in the glass house for 6 weeks during which water was withheld to induce stress. Observations were made on number of dead plants and days to wilting point, the results were analyzed and 12 best performing cultivars were selected for field trials. The field trial was carried out in Lwamondo, Thohoyandou for 6months under rain-fed conditions. The experiment was conducted in a complete randomized block design with 6 replicates.Yield data and growth parameters were collected every 8 weeks during the trial period and the data collected was analyzed using ANOVA. The best performing cultivars were Zapallo, Tacna, Ejumula, 2004-9-2 and Ndou. They were therefore recommended for further evaluation in other drought prone areas of the country. / Agriculture and  Animal Health / M. Sc. (Agriculture)

Sweetpotato (Ipomoea batatas (L.) Lam.) is a root crop well established throughout the world's tropical and sub-tropical regions. Despite sweepotato's importance, it has been under-researched relative to many other major crops. The main objective of this thesis is to contribute to a fuller understanding of the genetic and physiological factors underlying the production of sweetpotato storage roots for human consumption. The sweetpotato genome is diverse and subject to high levels of natural somatic mutation. Applying the AFLP (amplified fragment length polymorphism) technique allowed a direct comparison of inter and intra-cultivar DNA (deoxyribonucleic acid) base sequence variation. Analysis of the variation indicated that although sweetpotatoes are clonally propagated, clones show a lack of genetic fidelity to their source. Further, the level of genetic variation within the cultivar 'Owairaka Red' indicated the continuing emergence of distinct new strains. Plant field establishment represents the interaction of both propagation and growth phases of storage root production. A range of establishment techniques were investigated in a field trial under commercial conditions. Sprouts cut from seed roots and held for six days rather than immediate planting improved establishment as measured by growth, at little expense. Plug raised plants also improved establishment, while potentially reducing the degree of intra-cultivar genetic variation. Plant carbohydrate partitioning in three cultivars, 'Beauregard', 'Beniazuma' and 'Owairaka Red' was examined by field trial over the period of storage root growth. While cultivars differed in the proportions of dry matter partitioned to leaf, stem and root organs, the cultivar specific ratios of leaf to stem dry weight were relatively stable over time. Total storage root dry weight increased with time for all cultivars, but the distribution of storage root grades by size was cultivar specific. Within the storage roots % dry weight increased over time in all cultivars, but total sugar concentration only increased for 'Beauregard' and 'Beniazuma'. Finally, a storage root disorder called 'brown centre' curtails the temperate growing season so was investigated using low temperature storage and a field trial with various nutrition regimes. The disorder was found to be associated with susceptible germplasm, high soil nitrogen and harvest time.