Thesis (M. Agricultural Management (Agronomy)) -- University of Limpopo, 2018 / A survey study identified indigenous leafy vegetables (ILVs) utilized by rural communities in Limpopo Province in the three districts of Capricorn, Sekhukhune and Vhembe focusing on their availability, agronomic practices, marketing, medicinal and cultural roles, as well as their nutritional value. An ILV that was highly preferred and with good marketing potential was identified for further studies on its response to planting density and nitrogen fertilizer rate. A questionnaire survey was used to gather information about types of ILVs utilised, their production practices, marketing of ILVs and their importance in medicinal and cultural roles. Data collected were subjected to analysis using the Statistical Package for Social Sciences (SPSS) using descriptive statistics. Results showed that there were 45 different types of ILVs identified from the three districts in Limpopo Province. Farmers indicated that cultivation of these vegetables was mostly done from October to January in Sekhukhune and Capricorn district while in Vhembe it was practiced all year round. Most of farmers in Vhembe district used inorganic fertilizer during planting while farmers in Sekhukhune and Capricorn districts used organic fertilizers such as cattle manure. Irrigation was commonly used in Vhembe district through furrow irrigation system whereas in Capricorn and Sekhukhune districts most farmers relied on rainfall. Farmers indicated that harvesting was done at an early growing stage of the crop. Indigenous leafy vegetables were mostly marketed in local communities. Several ILVs were identified as preferred and regularly consumed as vegetables. Spider plant (Cleome gynandra) and nightshade (Solanum retroflexum) were identified as the most consumed ILVs in the three districts. Comparing the market potential of the two vegetables, S. retroflexum was chosen for further studies on its response to plant density and nitrogen fertilizer rate. The first study investigated the effect of varying plant density (inter and intra-row spacing) and the second study evaluated the response of intra-row spacing and nitrogen fertilizer (LAN-28%N) rate on growth and yield of S. retroflexum during 2014 (April to May) and 2015 (March to May) growing seasons. The plant density experiment was laid out as a 3 x 4 factorial arrangement in a randomised complete block design (RCBD) with three replications. The treatment factors were 3 inter-row spacings of 30, 45 and 60 cm and 4 intra-row spacings of vi 7.5, 15, 22.5 and 30 cm. The data collected included plant height, plant vigour, number of leaves and branches per plant as well as plant leaf yield. Data were subjected to analysis of variance (ANOVA) using STATISTIX 10.0 package and mean treatments were separated using Turkey HSD at 5% probability level. The results revealed that growth parameters (plant height, plant vigour, number of branches and leaves) and plant leaf yield were significantly influenced by the combined inter and intra-row spacings. Closer inter-row spacings of 30 cm and 45 cm, and intra-row spacings of 7.5 and 15 cm produced the highest values of parameters and plant leaf yield. The combined spacings of 30 x 7.5 cm produced the highest plant leaf yield. The second study was also laid out as a randomised complete block design (RCBD) with three replications. The treatments were 6 x 2 factorial arrangement: 6 levels of nitrogen (LAN-28%N) at 0, 20, 40, 60, 80 and 100 kg N/ha and two intra-row spacings of 15 and 30cm. Inter-row spacing of 30 cm was used. The nitrogen fertilizer was applied a week after transplanting and repeated a week after first harvesting. Data was subjected to analysis of variance (ANOVA) using STATISTIX 10.0 package. Where significant differences were detected, means were separated using Turkey HSD at 5% propability level. The results suggested that both nitrogen fertilizer and spacing can be used to enhance growth and leaf yield of S. retroflexum vegetable. Nitrogen fertilizer rate and plant density significantly (P≤0.05) affected plant growth and plant leaf yields. Growth parameters and leaf yield were optimised using closer spacing of 15 cm and applying nitrogen at 60 kg N/ha. The application of 60 kg N/ha and 15 cm spacing was therefore recommended for the production of S. retroflexum as a vegetable, if planted at 30 cm inter-row spacing. Key words: Indigenous leafy vegetables, agronomic practices, Solanum retroflexum, planting density, nitrogen fertilizer, planting date

Thesis (MSc. (Agricultural Economics)) -- University of Limpopo, 2014 / There are few plant species commercialised significantly globally and food requirements are mainly met by only few species. However, there is an enormous number of under-utilised species that play a vital role in the livelihood of rural households. These species are referred to as indigenous crops. Indigenous crops are adaptable to local agro-ecological conditions even where there is unreliable rainfall, which is the case in many parts of the country, require a minimum production management, mature early, and are easy to harvest and preserve and require less capital investments. Despite all these, in South Africa indigenous leafy vegetables (ILVs) were not commercialised and most researchers did not pay much attention to do research on possibilities of commercialising these crops. Thus this study investigated the economic potential of commercialising indigenous leafy vegetables in the rural South African context in general and in the study area in particular. The objectives of the study were (1) to identify the socio-economic characteristics of ILVs producers in rural areas of Capricorn district, (2), to investigate constraints faced by farmers in commercialising ILVs in rural areas of Capricorn district, (3), to determine the productivity of indigenous leafy vegetables in rural areas of Capricorn district, and (4), to assess different types of marketing channels of ILVs in rural areas of Capricorn district. The study used Stochastic Frontier Production Function to determine the productivity and to assess the socio-economic characteristics of producers of Indigenous Leafy Vegetables. Bubble chart was used to assess the marketing channels whilst consumer data was captured into a statistical package. The results indicated that there are several significant socio-economic factors that affect ILV production and there are also factors which constraint farmers from commercialising ILVs. Productivity of ILVs in the study area varied a lot among farmers; some farmers had a high productivity but most farmers had a low productivity. The results indicated that out of the factors included in the analysis significant production factors were; amount of labour used, cost of hiring tractor service and land devoted to ILVs and inefficiency factors were; gender, age, household size, farming experience, farm size, v hired labour, primary occupation and land ownership. ILV farmers had no formal marketing channels; they sold their product direct to consumers or through hawkers. Therefore, the study recommends the integration of science/modern technology and indigenous knowledge, to improve the productivity of ILVs. Since farmers were not technically efficient, therefore it is important to run workshops that will help them improve their production and marketing skills and how to market their products. Or create booklets that have information on how to efficiently produce ILVs. There should also be awareness campaign on the benefit of ILVs in both rural and urban communities. The study also recommends a multi-disciplinary approach in developing the crop; more stakeholders should be involved so as to make the crop appealing. Finally the study recommends the commercialisation of these crops due to the fact that they have the potential and are demanded in most parts of South Africa.

LEAFY (LFY) est un facteur de transcription central pour le développement des plantes, en particulier pour la floraison chez les angiospermes. LFY est très conservée, même chez les espèces ne portant pas de fleurs. On dispose de nombreuses données génétiques sur LFY et son réseau de régulation chez la plante modèle Arabidopsis thaliana, mais les mécanismes moléculaires impliqués dans son fonctionnement ne sont pas entièrement élucidés. LFY possède deux domaines conservés : un domaine de liaison à l'ADN et un domaine de fonction inconnue en position N-terminal. L'objectif a été de comprendre le rôle du domaine N-terminal et d'étudier l'évolution de la spécificité de liaison à l'ADN de LFY. Nous avons obtenu la structure cristallographique du domaine N-terminal de LFY et découvert qu'il s'agissait d'un domaine SAM (Sterile Alpha Motif) permettant l'oligomérisation de la protéine. Nous avons validé l'importance de cette propriété pour la fonction florale de LFY chez A. thaliana. Nous avons ensuite montré, par des analyses in vitro et in vivo en ChIP-seq que l'oligomérisation influençait la liaison à l'ADN en permettant une liaison coopérative sur plusieurs sites de liaison, en assurant la sélectivité de la protéine vis-à-vis de l'ADN et en permettant l'accès de la protéine à des régions génomiques où la conformation de la chromatine est normalement défavorable à la liaison. Cette étude intégrative a permis de mieux comprendre le fonctionnement de LFY. Des modifications dans les réseaux de régulation de l'expression des gènes sont source de nouveauté et d'évolution. LFY étant très conservée et ne faisant pas partie d'une famille multigénique, nous nous sommes demandé si sa spécificité de liaison à l'ADN avait évoluée. Nous avons montré que LFY était apparue chez les algues multicellulaires et que sa spécificité avait connue au moins deux changements majeurs au cours de l'évolution. Nous avons expliqué ces modifications au niveau moléculaire par des approches de biologie structurale et de biochimie. Nous avons identifié une espèce chez qui LFY a une spécificité relâchée et nous proposons qu'une telle forme ait pu permettre les transitions d'une spécificité à une autre.

Made available in DSpace on 2015-04-17T14:49:22Z (GMT). No. of bitstreams: 1 Arquivototal.pdf: 2587496 bytes, checksum: 770af7c77e4e43893609f4e8cfe5c7eb (MD5) Previous issue date: 2012-09-04 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Spinach is a dark green leafy vegetables in the diet that helps with the intake of vitamins, proteins, minerals, especially calcium and iron, and bioactive compounds not common in other plants. The objective of this research was to characterize the spinach Tetragonia tetragonoides, fresh and powdered (bleached and un bleached) on the content of nutrients, antinutritional and bioactive compounds, evaluating the effects of bleaching on these compounds, the antioxidant capacity of bioactive compounds and functional potential of spinach bleached powder as an ingredient in the formulation of bread. The powder of spinach leaves, subjected to bleaching, decreased concentrations of nutrients, antinutritional and bioactive compounds, compared to the same product is not bleached. The greatest losses were observed for iron (19,4 %), calcium (18,3 %), oxalic acid (36,4 %), phytic acid (33,5 %) and ascorbic acid (18,74 %). The reduction in bioactive compounds resulted in lower antioxidant capacity of spinach powder bleached, as assessed by FRAP methods and linoleic β-caroteno/ácido, however, this effect was not observed by the DPPH method, and spinach powder, subjected or not to bleaching, presented the same antioxidant power. When the spinach bleached powder was added to the formulation of the loaf of bread, the concentrations of 1 %, 2 % and 3 % was observed better sensory acceptability in the formulation of 3 % was noted that the other as the softness. This formulation showed a higher content of protein, calcium, iron and phosphorus than the control bread. Therefore, the use of spinach as an ingredient of bread can be a good alternative to inclusion of the hardwood vegetables in the diet, contributing to improved nutrition and presenting, in the form bleached, reduced antinutritional content. / O espinafre é uma hortaliça folhosa verde-escuro que presente na dieta contribui com o aporte de vitaminas, proteínas, minerais, especialmente cálcio e ferro, e compostos bioativos não comuns em outros vegetais. O objetivo na presente pesquisa foi caracterizar o espinafre Tetragonia tetragonoides, in natura e em pó (branqueado e não branqueado) quanto ao teor de nutrientes, antinutricionais e de compostos bioativos, avaliando os efeitos do branqueamento sobre esses compostos, a capacidade antioxidante dos compostos bioativos e a utilização do espinafre em pó branqueado como ingrediente na formulação de pão de forma. O pó das folhas de espinafre, submetidas ao branqueamento, apresentou redução nas concentrações dos nutrientes, antinutricionais e compostos bioativos, quando comparado ao mesmo produto não branqueado. As maiores perdas foram observadas para ferro (19,4 %), cálcio (18,3 %), ácido oxálico (36,4 %), ácido fítico (33,5 %) e vitamina C (18,74 %). A redução nos compostos bioativos resultou em menor capacidade antioxidante do espinafre em pó branqueado, quando avaliado pelos métodos FRAP e β-caroteno/ácido linoléico, entretanto, esse efeito não foi verificado pelo método DPPH, tendo o espinafre em pó, submetido ou não ao branqueamento, apresentado o mesmo poder antioxidante. Quando o espinafre em pó branqueado foi adicionado à formulação do pão de forma, nas concentrações de 1 %, 2 % e 3 %, observou-se uma melhor aceitação sensorial para a formulação com 3 %, que se destacou das demais quanto à maciez. Essa formulação apresentou maior teor de proteínas, cálcio, ferro e fósforo que o pão controle. Portanto, a utilização do espinafre como ingrediente de pão de forma pode ser considerada uma boa alternativa de inclusão dessa hortaliça folhosa na dieta, contribuindo para a melhoria nutricional e apresentando, na forma branqueada, reduzido teor de antinutricionais.

As folhas das angiospermas sofreram grandes modificações funcionais e estruturais ao longo do tempo, e atualmente apresentam uma ampla diversidade de formas, tamanhos e arranjos. Por exemplo, na tribo Bignonieae (Bignoniaceae), as folhas são geralmente 2-3-folíoladas, e o folíolo terminal é frequentemente modificado em gavinha. As gavinhas dos representantes de Bignonieae apresentam formas variadas (simples, bífidas, trífidas ou multífidas) e estão possivelmente envolvidas na diversificação da tribo. Apesar da importância das gavinhas para as plantas escandentes, pouco ainda é conhecido sobre esses órgãos nas angiospermas. Atualmente, existem dados disponíveis sobre genes que controlam o desenvolvimento de gavinhas foliares apenas para Pisum sativum (ervilha). Embora a maioria das angiospermas tenha o desenvolvimento de suas folhas controlado pelos genes KNOX1, em P. sativum, KNOX1 não é expresso nos primórdios foliares e seu desenvolvimento é regulado por LEAFY/FLORICAULA (LFY/FLO). Esses dados sugerem que folhas com gavinhas em outras espécies de planta também podem ser reguladas exclusivamente por LFY/FLO. O presente estudo investigou a evolução e o desenvolvimento dos diferentes tipos de gavinhas em Bignonieae e visou entender como mudanças na morfogênese foliar geraram os padrões atuais de variação morfológica das mesmas. Analisou-se o padrão de expressão dos genes SHOOTMERISTEMLESS (STM, gene KNOX1), PHANTASTICA (PHAN) e LFY/FLO durante o desenvolvimento foliar de três espécies de Bignonieae com diferentes tipos de gavinhas (simples, trífidas e multífidas), buscando um melhor entendimento da estrutura geral, origem e base genética do desenvolvimento das gavinhas foliares neste grupo. Nossos resultados demonstraram que as folhas se desenvolvem de maneira acrópeta em Bignonieae, bem como indicaram que gavinhas trífidas são ancestrais na tribo, com a evolução dos outros tipos de gavinhas tendo envolvido mudanças heterocrônicas no padrão de desenvolvimento básico das folhas. Além disso, transcritos do gene STM foram detectados em folhas em desenvolvimento, revelando que as folhas em Bignonieae se desenvolvem de maneira diferente das folhas de P. sativum, embora ambas apresentem gavinhas. Analises anatômicas revelaram que as gavinhas apresentam simetria bilateral e possuem algumas características similares aos folíolos, corroborando indicações previas de que as gavinhas de Bignonieae representariam folíolos modificados. Estas conclusões foram reforçadas pelo padrão de expressão encontrado para o gene PHAN (gene de identidade adaxial), cujos transcritos estavam confinados ao domínio adaxial do primórdio de gavinha em espécies que possuem gavinhas ramificadas, num padrão muito similar ao padrão observado nos primórdios dos folíolos. Em B. callistegioides, espécie que possui gavinhas simples, PHAN é expresso uniformemente por toda a gavinha, indicando que o domínio adaxial não foi corretamente estabelecido. Assim, as diferenças encontradas nos padrões de expressão do gene PHAN entre espécies com diferentes tipos de gavinhas em Bignonieae indica a existência de uma possível correlação entre a expressão do PHAN com a ramificação de gavinhas. Além disso, o padrão de expressão encontrado sugere que PHAN pode ter um papel importante no estabelecimento da polaridade em gavinhas e no surgimento dos vários tipos de gavinha encontrados na tribo. Além disso, o padrão de expressão do LFY/FLO em primórdios foliares nos levou a inferir que LFY/FLO pode ter um papel importante na separação de novos órgãos a partir de zonas meristemáticas. / Angiosperm leaves have undergone major functional and structural modifications over time, and currently exist in a wide diversity of forms, sizes, and arrangements. For example, in the tribe Bignonieae (Bignoniaceae), leaves are generally 2-3-foliolated, and the terminal leaflet is often modified into tendrils.These tendrils present varied morphologies (simple, bifid, trifid or multifid) and are thought to have been involved in the diversification of Bignonieae. Despite the importance of tendrils for climbing plants, little is still known about the biology of tendrils in the angiosperms. To date, no data is available on the genes that control tendrilled-leaf development in species other than pea (Pisum sativum). Even though KNOX1 genes control leaf development in the majority of compound-leaved angiosperms, in pea, KNOX1 is completely excluded from the leaf primordium and its development is regulated by LEAFY/FLORICAULA (LFY/FLO). This observation suggests that the development of other tendrilled-leaves might also be exclusively regulated by LFY/FLO as well. This study investigated the evolution and development of tendril types in Bignonieae in order to further understand how changes in leaf morphogenesis led to current patterns of variation in tendril morphology. We further analyzed the expression patterns of SHOOTMERISTEMLESS (STM, KNOX1 gene), PHANTASTICA (PHAN) and LFY/FLO during leaf development in three representatives of Bignonieae with different tendril types in order to better understand the structure, origin and genetic basis of leaf tendrils in this plant clade. Our results demonstrate that leaves in Bignonieae develop acropetally, as well as indicates that trifid tendrils are ancestral in the tribe, with the evolution of other tendril types involving heterochonic shifts in the leaf basic developmental pathway. Furthermore, transcripts of STM were detected in developing leaves, revealing that tendrilled leaves of Bignonieae develop differently from those of pea. The anatomical analysis revealed that tendrils are bilaterally symmetrical and present some characteristics that are similar to leaflets, further corroborating earlier suggestions that tendrils indeed represent modified leaflets. This observation was further reinforced by the expression pattern of PHAN (an adaxial identity gene), as PHAN transcripts were confined to the adaxial domain of the tendril primordia in branched-tendrilled species, in a pattern very similar to that observed in leaflet primordia. In B. callistegioides, a simple-tendrilled species, PHAN was expressed throughout the entire tendril, indicating a certain degree of disruption in the establishment of the adaxial domain. The differences encountered in the expression pattern of PHAN amongst species with different tendril types indicate a possible correlation of the expression of PHAN with tendril branching. Furthermore, it suggests an important role for PHAN in the establishment of tendril polarity and in the rise of the various tendril types encountered in Bignonieae. In addition, the pattern of expression of LFY/FLO in developing leaves has led us to infer that LFY/FLO may present an important role for the separation of new organs from meristematic zones.

Philosophiae Doctor - PhD / Starch is a major carbohydrate reserve in many plants, providing energy during heterotrophic growth and it is contained in large amounts in staple foods such as potatoes, wheat, maize, rice, sorghum and cassava. Apart from being a major product for use in the food industry, starch is also attracting interest from the biofuels industry as a source of bioethanol. This study reports on the development of genetic tools aimed at increasing starch production in sorghum (Sorghum bicolor L Moench), a crop of key agronomic importance worldwide by exploiting a new discovery of a transcription factor gene that regulates starch accumulation in Arabidopsis thaliana namely LEAFY COTYLEDON I (LECl). Ectopic over expression of this gene in arabidopsis has previously been shown to induce a massive hyper accumulation of starch in vegetative tissues. Therefore, we set out to investigate the function of its orthologous gene counterpart in sorghum with the aim of manipulating starch yield directly. Deduced protein sequence analyses showed that the putative sorghum LEAFY COTYLEDON I gene (SbLEC1) cloned in this study shares an overall high amino acid sequence identity (70 %) with the arabidopsis LEC 1, while the functional central B domain shows an even higher percentage sequence identity (91 %) with the same region of arabidopsis LEC 1. The putative SbLEC1 protein shares 14 out of the 16, signature ammo acids characteristic of the Central B Domain with arabidopsis. Furthermore, the putative SbLEC1 protein was also shown to share a significantly high sequence identity (> 80 %) with other well-characterized LEC1 protein sequences from organisms such as maize, rice, rapeseed as well as other organisms documented in the NCB I database. Similarly, much of the sequence similarity lies within the functional central B domain compared to any other region. Gene expression profiling using semi-quantitative PCR showed that SbLEC1 transcripts accumulated in developing seeds as well as in embryogenic calli tissue and no SbLEC 1 transcripts were detectable in leaf, root or sheath tissue. In order to confirm that the identified transcription factor is a functional ortholog, the full cDNA encoding putative SbLEC 1 transcription factor was identified, isolated and cloned from the sweet sorghum MN 1812 genotype. Plant transformation gene constructs based on the pCAMBIA1305.2 binary vector harbouring the transcription factor gene under the control of different promoter sequences were then assembled and immobilized into Agrobacterium tumefaciens strain LBA4404 in preparation for sorghum and arabidopsis transformation. Transient GUS expression studies showed that the five SbLEC1 gene constructs developed in this study were successfully transformed into arabidopsis (Ws ecotype) and sorghum (variety MN1812) callus and cell suspension cultures. The transformed tissues thus represent essential tools that are useful to evaluate the effect of over expressing the putative SbLEC1 protein. Transient GUS expression assays also further revealed differences in efficiency among promoters in driving transgene expression. Transient GUS activity was highest for the maize ubiquitin promoter (MUbi1), followed by the sorghum LEC1 promoter (SLECP), the arabidopsis LEC1 promoter (ALECP) and lastly the maize alcohol dehydrogenase promoter (MAdh1). The ability of the putative SbLEC 1 gene to complement the arabidopsis lecI mutation was also investigated and our findings were not conclusive as they only revealed partial complementation. A detailed comparison of SbLECI full cDNA sequences isolated and cloned from twenty-eight different F2 population plants from different sorghum varieties revealed the existence of sequence variation within the SbLEC 1 gene, which appeared to be allelic. The allelic variation was further shown to affect the amino acid composition of the putative SbLEC 1 protein. Heterologous protein expression studies of the SbLECI gene using an E. coli system showed that the predicted 29.16 kDa putative SbLEC 1 protein could be expressed in vitro both as an development of an efficient tissue culture protocol is a prerequisite for plant genetic engineering, this study also reports on the evaluation of thirteen sorghum genotypes from different genetic backgrounds for their in vitro culture response. A tissue culture protocol for three previously unexplored sorghum genotypes namely Agricol white, AS4 and MNI812 was established. The effect of plant genotype, explant and medium composition on in vitro culture response was highly significant (95 % Cl) in this study. Taken together, the findings in our study demonstrate efforts to draw a baseline foundation for the development of molecular technologies that can be used to increase starch production in sweet sorghum as a water efficient and sustainable feedstock for biofuel production.

Leafy spurge (Euphorbia esula L.) is a costly noxious weed to manage in the Northern Great Plains; it invades rangelands and displaces native and desirable vegetation. Our first objective was to test the recommended full rate and half rate of selected herbicides applied in September following a spring burn on a leafy spurge invaded plant community. Our second objective was to determine if raffinate (desugared beet molasses) applied to leafy spurge invaded rangeland would attract cattle to consume leafy spurge. The aminocyclopyrachlor with chlorosulfuron treatment had the best leafy spurge control at the full rate, with stem density reductions of 95 percent for both sites nine and twelve months after treatment. The salt block treatment had the best success at reducing leafy spurge stem density. Herbicides can be the most common and effective type of management; however, manipulating livestock to graze noxious weeds converts a weed into a useable forage.

The presence of postharvest sanitizers has shown to be an effective approach to reducing microbial cross contamination in agricultural washing operations. However, choosing an appropriate sanitizer can be challenging due to produce commodity, processing conditions and interference with organic load. Current research shows a wide variety of methods to mimic the organic load of vegetable processing conditions, with paddle mixing and blender as the most commonly used. Controlling and understanding the physiochemical properties of wash water is key in maintaining sanitizer efficacy. The effects of simulated wash water preparation method on the physiochemical properties were tested at 0 and 50 COD(mg/L) and no significant difference was observed. However, at high levels of organic load results showed a significant difference between turbidity values at 1,500 COD. Free residual chlorine titration methods were compared, using DPD-titrimetric and Iodometric method. Results showed a significant difference between titration methods in organic load heavy environments. Commercially available chlorine based sanitizers, Pure Bright™ Germicidal Bleach and Clorox® Germicidal Bleach, were compared to a concentrated solution of sodium hypochlorite. Pure Bright™ Germicidal Bleach showed to perform the best by reducing 7 log CFU/ml of E. coli O157:H7 after 30 seconds in no organic load environments, whereas Clorox Germicidal bleach was able to reduce 7 log CFU/ml of E. coli O157:H7 after 30 minutes. These studies aim to provide best management practices for small in medium growers in the implementation of antimicrobial solutions for the maintenance of water quality in postharvest washing solutions.

AIM AND OBJECTIVES The main aim of this thesis was to explore the possibilities of promoting the cultivation, utilisation and consumption of indigenous and traditional plant foods (ITPF) among urban and rural communities in the North West Province of South Africa that could possibly lead to increased IK and dietary diversity. The objectives were the following: Assess consumption of TLV in the rural and urban communities. Compare nutritional status of consumers and non-consumers of TLV using data obtained from the Prospective Urban and Rural Epidemiology (PURE-SA) study. Assess the availability, cultivation and consumption patterns of ITPF. Assess indigenous knowledge (IK) within the rural and urban communities. Assess consumers’ views of ITPF in the rural and urban communities. Assess consumers’ acceptance of, preference for and consumption intent of dishes made from cowpea leaves. To compile recipes for the most important ITPF commonly consumed in the study areas in order to promote the cultivation and consumption of ITPF (see Addendum D). STUDY DESIGN Health profile study: For the health profile study, a comparative study was conducted on the baseline data of the population that participated in the PURE-SA study (1004 urban and 1006 rural participants) which follows the health transition in urban and rural subjects over a 12 year period. The baseline data for the North West Province of South Africa were collected from October to December 2005. Utilisation of ITPF study: The study on the utilisation of ITPF used a sequential explanatory study design which involved the collection of quantitative and qualitative data and analyses. The consumer acceptance study consisted of an explorative and experimental phase. Participants were male and female, aged older than 20, residing in the selected communities and knowledgeable on the indigenous and traditional foods of the area. METHODS A variety of quantitative and qualitative research techniques were used. Data were generated through questionnaires, focus groups and individual - and group interviews. Health profile study: Demographic characteristics and frequency of consumption of TLV data were collected by the researcher from 396 randomly selected subjects from participating subjects in the PURE-SA study. An extensive nutritional profile of these subjects was compiled including blood samples, blood pressure, anthropometric measurements and total dietary intake by means of a quantitative food frequency questionnaire. Utilisation of ITPF study: A comparative study was conducted in rural and urban populations of the North West Province. Data were collected by the researcher using a questionnaire (n=396 households), key informant interviews (n=4), and four focus groups. Consumer study: Four focus groups were conducted by the researcher, two in rural and two in urban communities, to investigate consumers’ views about ITPF. Eighty-seven participants were recruited based on a specific purpose rather than randomly. Consumers’ acceptance of, preference for and intended consumption of products made with cowpea leaves were assessed. A 5-point hedonic scale and a 7-point food action rating scale were used for sensory evaluation. RESULTS Health profile study: As expected, rural inhabitants were more likely to consume TLV. However, no household reported to consume TLV more than ten times a month. Factors such as price (affordability) and availability and easy-to-get-to points of purchase were found to be major constraints in the consumption of TLV, especially in urban communities. Urban respondents had significantly higher macronutrient intakes than rural subjects. There was no significant difference between the selected micronutrient intakes between consumers and non-consumers of TLV. Non-consumers of TLV had higher blood lipid levels than consumers from both the rural and urban areas. In the urban subjects the relative risk to develop high blood pressure was higher in non-consumers of TLV than in the consumers. However, the risk ratios of raised serum cholesterol and triglycerides were not significantly different. Utilisation of ITPF study: More plant foods were available and consumed in the rural area than the urban area. However, fewer species were available than expected due to insufficient rainfall, poor soil quality, deforestation and over harvesting. Consumption of indigenous foods was influenced by price, culture, seasonality/availability, accessibility and diversity in markets. A lack of markets for indigenous crops, insufficient rainfall and diseases and pests were cited as the major cultivation problems, followed by a lack of capital to buy farming implements, veld fires and poor soil quality. Consumer study: Based on the qualitative focus group discussions, factors that influence the consumption of ITPF were identified. These factors included benefits and barriers of ITPF consumption. Ways to increase ITFP consumption were also identified. Health and nutrition; tradition and culture; and food safety emerged as drivers for ITPF consumption. A lack of knowledge and skills of food preparation and negative images and unfamiliarity of ITPF acted as barriers. Differences in views existed between older and younger consumers. In general younger consumers found ITF rather revolting and undesirable, humiliating to consume. Sensory evaluation of food samples for the pooled data of the total study population showed that significant differences existed between the acceptability of all attributes, overall acceptance and consumption intent. Socio-demographic backgrounds such as place of residence (urban or rural), levels of education and age were shown to influence the acceptability of food samples and consumption intent. There was no positive association between acceptability of food and gender. CONCLUSIONS Health profile study: This study showed the possibility of beneficial effects of rural diets, however, the lack of knowledge concerning the bioavailability of nutrients from TLV and lack of information on food consumption database, of these vegetables constitute main barriers to obtaining information on nutrient intake. The low frequency of consumption of TLV is of concern. Taking into consideration safe agricultural practices, the promotion of TLV might be a solution towards healthier diets and combating poverty. More research is needed to investigate the health effects of these vegetables. Utilisation of ITPF study: It is evident that there was a limited number of ITPF species cultivated and consumed. Consumers, especially older people, were found to possess extensive knowledge regarding the availability of ITPF species, their habitat and uses, seasonality and potential health benefits. There is a need to intensify education on conservation of natural resources and more studies should be undertaken to document and disseminate traditional food systems. In addition, there is a need to integrate existing health and nutrition interventions with traditional food promotion. Consumer study: The results highlighted the importance of making use of a mixed method approach which made it possible not only to identify factors that influence the consumption of ITPF but also to understand the dynamics thereof from focus group discussions and how they influence acceptability, preference and consumption intent. Important benefits (drivers) of and barriers to ITPF consumption as well as suggestions on how to increase ITPF consumption were identified. Barriers to ITPF consumption and low scores of acceptability provided by younger participants can be connected to misconceptions about ITPF and lack of familiarity with the products. Therefore, a combination of strategies aimed at enhancing individual awareness of the health benefits of ITPF, decreasing barriers and conducting more acceptability studies may have a positive impact on the younger segment of the population. / Thesis (Ph.D. (Consumer Science))--North-West University, Potchefstroom Campus, 2012

A contaminação do ambiente é crescente no mundo, com grandes extensões de áreas afetadas por metais pesados em concentrações que podem representar perigo ambiental. Em face ao aumento da atividade industrial e à agricultura altamente tecnificada, é fundamental o monitoramento dos níveis de metais pesados nos solos, já que as plantas se comportam como mecanismo de transferência de contaminantes do solo para níveis mais altos da cadeia trófica. A ingestão de vegetais contendo elevadas concentrações de metais pesados é uma das principais vias de acesso desses elementos ao corpo humano. No corpo humano, os metais pesados depositam-se no tecido ósseo e gorduroso, ocupando o lugar de minerais nobres. Lentamente liberados no organismo, podem provocar uma série de doenças. O projeto foi dividido em três etapas, cada qual com um objetivo específico: 1º) determinar as concentrações de cádmio, níquel, chumbo, cobalto e cromo em vegetais frequentemente consumidos no Estado de São Paulo, e compará-las com os limites estabelecidos na legislação brasileira; calcular a ingestão diária de metais pesados para estimar o risco à saúde humana; identificar as culturas que apresentam maior potencial de translocação de cádmio para a cadeia alimentar 2º) avaliar os teores de cádmio em hortaliças e nos solos dos campos de produção 3º) avaliar a disponibilidade de cádmio do solo para as plantas com maior potencial de acúmulo do mesmo, com auxilio de extratores químicos e pela técnica de traçador radioativo (109Cd). As amostras vegetais foram coletadas na Companhia de Entrepostos e Armazéns Gerais de São Paulo e a concentração de metais pesados foi determinada por espectrometria de absorção atômica. Todos os vegetais analisados apresentaram concentrações de Cd e Ni abaixo do limite tolerável estabelecido pela legislação brasileira. No entanto, para Pb e Cr, 44% das amostras excederam o limite permitido. Não há nenhuma recomendação estabelecida de limite máximo de tolerância para Co no Brasil. Quanto ao hábito de consumo da população do Estado de São Paulo, a ingestão diária de metais pesados está abaixo da máxima permitida, consequentemente o consumo desses alimentos pode ser considerado seguro e sem riscos à saúde humana. As hortaliças folhosas foram as que mais acumularam Cd. Algumas regiões do Estado de São Paulo apresentaram teores totais de Cd no solo acima do valor de intervenção estabelecido pela CETESB. Entretanto, os vegetais cultivados nesses locais apresentaram teores de Cd inferiores ao limite máximo de tolerância, estabelecido pela ANVISA. É importante, ao estudar a contaminação de áreas agrícolas por metais pesados, observar, além do teor total, outros parâmetros, como a sua disponibilidade para plantas. No experimento em casa de vegetação, as correlações entre o Cd disponível do solo e o Cd acumulado pelas plantas foram significativas somente para a rúcula. O extrator mais eficiente em determinar a fitodisponibilidade de Cd, analisado por meio do Valor L e Razão L, foi o extrator Ácidos Orgânicos / The environmental contamination is increasing worldwide, with large areas affected by heavy metals at concentrations which may pose environmental hazard. Due to industrial activity and highly technical agriculture, it is important to monitor heavy metals levels in soils, since vegetables behave as transfer mechanism of contaminants from soils to higher levels of the food chain. Ingestion of vegetables containing high concentrations of heavy metals is one of the main ways in which these elements enter the human body. Once in human body, heavy metals are deposited in the bone and fat tissues, overlapping noble minerals. Slowly released into the body, heavy metals may cause an array of diseases. The project was divided into three stages, each one with a specific objective: 1st) to determine the concentrations of cadmium, nickel, lead, cobalt and chromium in the most frequently consumed foodstuff in the São Paulo State, Brazil and to compare the heavy metal contents with the permissible limits established by the Brazilian legislation; to calculate intake of heavy metals in human diets for estimating the risk to human health; and to identify crops with the greatest potential for translocation of cadmium into food chain 2nd) to evaluate the cadmium content in leafy vegetables and soils at crop fields 3th) evaluate the phytoavailability of cadmium for leafy vegetables with aid of chemical extractants and radioactive tracer technique (109Cd). The vegetable samples were collected at São Paulo General Warehousing and Centers Company, and heavy metal content was determined by atomic absorption spectrophotometry. All vegetables sampled presented average concentrations of Cd and Ni lower than the permissible limits established by the Brazilian legislation. Exception for Pb and Cr in that 44% of the samples exceeded the maximum permitted limits. The Brazilian legislation has not established a permissible limit for Co contents. Regarding the consumption habit of the population in the São Paulo State, the daily ingestion of heavy metals is below the oral dose of reference, therefore, the consumption of these vegetables can be considered safe and without risk to human health. Leafy vegetables were those most accumulated Cd. Some regions of São Paulo State showed total contents of Cd in soil higher than intervention value established by CETESB. However, the vegetables grown in these areas showed Cd concentrations lower than Brazilian limit established by ANVISA. It is important, when studying environmental contamination by heavy metals, to observe, beside their total content, other parameters, like soil availability. In the greenhouse experiment, the correlation between soil available Cd and plants accumulated Cd were significant only for rocket. The most efficient chemical extractant in determining Cd phytoavailability, analyzed by L Value and L Ratio, were Organic Acids