Thesis (M.Sc. Agriculture (Agricultural Economics)) -- University of Limpopo, 2021 / Groundnut is one of the most important agricultural crops in South Africa. It provides economic and health benefits to the society. Its production, processing and marketing provides employment to several individuals in South Africa. The objectives of the study were: to identify and describe the socio-economic characteristics of small-scale groundnut farmers, analyse the determinants of commercialization and the factors influencing the choice of market outlet in Capricorn district. The study was conducted in three villages (Ga-Maja, Ga-Mphahlele and Moletjie). Purposive sampling technique was used to select 110 small-scale groundnut farmers. Semi-structured questionnaires were used to collect data from the small-scale groundnut farmers through face-to-face interviews. The data was analysed using the descriptive statistic, Logistic Regression and Multinomial Logit model. SPSS and STATA software were used to process the data. The results indicated that quantity of groundnut produced, occupation, marital status, household size, land size, vehicle ownership, access to credit and extension contact significantly influenced the commercialization and the choice of market outlet of the small-scale groundnut farmers in the study area. The study recommends that the government in collaboration with universities and agricultural colleges as well as the private sector initiate an extension programme that will focus on small-scale farmers, rather than on emerging and commercial farmers only. This will enable the small-scale famers to get access to information on the market, production, price and other agricultural related activities. It further recommends that the Department of Agriculture visit areas where farmers produce the same type of crops and offer them incentives to pool their resources and market their produce collectively. This will improve the bargaining position of the small-scale farmers as well as the means of lowering transaction costs. / National Research Foundation (NRF)

Since Senegal's independence in 1960, groundnuts (peanuts) have been the dominant agricultural export crop. Currently, groundnut output levels are on the decline and no clear reason for the downward trend has been found. Privatization efforts are underway as the government explores ways to breathe some life into the ailing sector, particularly as it relates to groundnut production. The 50 percent currency devaluation of 1994 constituted a major exogenous shock to the sector. Much research has been done about the macro-level impact of the changes that are taking place. However, little work has been done recently (i.e. since the devaluation) at the micro-level. This work addressed this lack by studying the micro-level dynamics of groundnut production. Elasticities were generated and used in the analysis of policy impacts on production. The own-price elasticity of supply groundnut indicated that supply response should be positive following an increase in producer price. The increase in producer prices following the devaluation did not occasion the expected supply response. Possible reasons for this failure were explored. It is hoped that the information revealed will complement the store of information on production in the Groundnut Basin that is already available. Thus, the present work will prove useful to public and private researchers and policy makers seeking to increase their understanding of the sector. / Master of Science

Bambara groundnut (Vigna subterranea L. Verdc) is a drought tolerant African legume capable of producing reasonable yields where other crops may fail. However, it remains an underutilised crop, owing to limited research, cultivated using landraces, of which scant information is available describing their agronomy and genetic diversity. The aim of this study was to evaluate the response of bambara landraces from different geographical locations to water stress under controlled and field conditions. Seeds were sourced from subsistence farmers of Tugela Ferry and Deepdale in KwaZulu-Natal (South Africa) and Zimbabwe, and characterised into three seed coat colours: light-brown, brown and red. Seed quality was assessed using the standard germination test. Vigour indices of germination velocity index and mean germination time were determined. Seedling establishment was evaluated using seedling trays using a factorial experiment, with four factors: 1. provenance – (Tugela Ferry and Deepdale), 2. seed colour – (red, light-brown and brown), 3. water regimes – (30%, 60% and 100% field capacity), and 4. soil media – (clay, sand and clay + sand). Seedling leaf samples were used to evaluate proline accumulation as an indicator of stress tolerance. A field trial was used to evaluate productivity of bambara landraces under rainfed and irrigated conditions. A pot trial was conducted under controlled environment conditions with three factors: temperature (33/27°C and 21/15°C), water regimes (30% and 100% of crop water requirement) and bambara landrace selections. Results showed no significant differences in germination capacity between bambara landrace selections. Germination time differed significantly (P<0.001) between bambara landrace selections. The Jozini provenance was shown to perform best, followed by Zimbabwe, Tugela Ferry and Deepdale. Brown landrace selections had higher (P<0.001) germination compared with red and light-brown selections, respectively. Seedling establishment showed that emergence was higher (P<0.001) at 100% FC compared with 60% FC and 30% FC. Emergence was higher (P<0.001) in the Sand+Clay mixture compared with Clay and Sand media. Dark-coloured selections had higher (P<0.001) emergence compared with light-coloured selections. Results from the field trial showed that the red landrace selections emerged better (P<0.001) than the light-brown and brown landrace selections, respectively. Plant growth was lower under irrigated compared with rainfed conditions. Stomatal conductance was higher (P<0.001) under irrigated compared with rainfed conditions, whereas chlorophyll content index was higher (P<0.05) under rainfed compared with irrigated conditions. Results of the pot trial showed that emergence was significantly (P<0.001) affected by temperature. It was higher at 33/27°C compared with 21/15°C (P<0.001). Dark-coloured landraces had higher emergence compared with the light-brown landraces. Stomatal conductance was lower at 30% ET relative to 100% ETc. There were no significant differences between water regimes with respect to biomass, pod number per plant, pod mass per plant, seed number per pod, seed mass per plant and harvest index. It is concluded that seed colour is an important variable in the identity of bambara landraces. Provenance plays a significant role in seed performance and there is a significant interaction between provenance and seed coat colour. This study could be expanded to obtain more data for crop improvement through inclusion of many sites and seasons for better agronomic advice to farmers. / Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.

Thesis (MTech (Food Technology))--Cape Peninsula University of Technology, 2015. / The aim of this study was to characterise the physicochemical, rheological, prebiotic and emulsion stabilising properties of four varieties (black-eye, brown-eye, brown and red) of Bambara groundnut (BGN) extracted using the modified wet milling method. A relatively high yield of BGN dietary fibres was obtained with soluble dietary fibres (SDFs) ranging from 15.4 to 17.1% and insoluble dietary fibres (IDFs) ranging from 12.0 to 15.6%. Black-eye and brown-eye dietary fibres showed superiority in terms of swelling capacities, water holding capacities, oil binding capacities, antioxidant properties as well as thermal stabilities than red and brown dietary fibres. In addition, black-eye and brown-eye dietary fibres were characterised by higher lightness (L*), redness (+a*), yellowness (+b*), chroma (C*) and hue. All four SDFs showed acceptable colour differences with ΔE < 8 ranging from 0.81 to 3.08. The hydrolysable polyphenolic (HPP) content of SDFs ranged from 6.89 to 20.86 mg/g GAE and that of IDFs ranged from 10.96 to 14.43 mg/g GAE. All four SDFs differed significantly (p < 0.05) in their HPP content. BGN IDFs were very low in tannins (< 2.2 mg/g).

Thesis MTech (Food Technology))--Cape Peninsula University of Technology, 2017. / Bambara groundnut (Vigna subterranea) an indigenous legume cultivated in Sub-Saharan Africa has been proclaimed to have medicinal properties from communities and in rural areas. However, there is not enough scientific information to validate these claims. Therefore, this study aimed to identify possible medicinal properties of Bambara groundnut (BGN), by analysing the phytochemical and antimicrobial properties of BGN seed and product extracts from Mpumalanga province within South Africa. The BGN extracts (70% methanol, 70% ethanol, milli-Q water) from seeds and products (milk and yoghurt) were screened for the presence of alkaloids, flavonoids, phenols, riboflavin and thiamine using analytical laboratory methods for basic screening, high-performance liquid chromatography (HPLC) and gas chromatography (GC) for quantification. The antimicrobial activity involved direct bioautography and minimum inhibitory concentration (MIC) against six antibiotic-resistant microorganisms, Acinetobacter baumannii ATCC 19606T, Enterococcus faecalis ATCC 29212, Klebsiella pneumoniae subsp. pneumoniae ATCC 700603, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus subsp. aureus ATCC 33591 and Candida albicans ATCC 24433. For the seed extracts, flavonoids and phenols were highly concentrated in the red and brown hulls of BGN compared to whole and dehulled BGN. Organic solvents in comparison to water yielded the highest concentration of flavonoids, whilst water yielded the highest concentration for phenols. Flavonoid compounds that were detected at the highest concentrations were rutin (24.458 ± 0.234 mg.g-1, brown hull extracted with 70% methanol), quercetin (0.070 ± 0.043 mg.g-1, red hull extracted with 70% methanol), kaempferol (0.391 ± 0.161 mg.g-1; brown hull extracted with 70% ethanol) and myricetin (1.800 ± 0.771 mg.g-1; red hull extracted with 70% methanol). For phenol compounds, gallic acid (0.009 ± 0.004 mg.g-1; brown hull extracted with milli-Q water), catechin (0.026 ± 0.041 mg.g-1; brown hull extracted with milli-Q water), methyl gallate (0.008 ± 0.013 mg.g-1; brown whole extracted with milli-Q water), chlorogenic acid (0.115 ± 0.199 mg.g-1; brown hull extracted with milli-Q water) and ellagic acid (0.105 ± 0.082 mg.g-1; red hull extracted with milli-Q water) were detected. Vitamins B1 and B2 (riboflavin and thiamine) were mostly present in milli-Q water extracts. Black-eye hull had the highest concentration of thiamine (vitamin B1) and riboflavin (vitamin B2) consisting of 0.072 mg.g-1 (extracted with milli-Q water) and 0.002 mg.g-1 (extracted with 70% ethanol and 70% methanol). Red and brown hull extracts from organic solvents (70% ethanol and 70% methanol) showed the highest antimicrobial activity, whereas the whole, dehulled and hulls (black-eye and brown-eye) extracts had no antimicrobial activity. As for BGN products extracts, flavonoid compounds that were detected at the highest concentrations were rutin (5.694 mg.g-1, whole BGN milk, milli-Q water), quercetin (0.703 mg.g-1, whole BGN yoghurt, milli-Q water) and myricetin (0.987 mg.g-1, whole BGN yoghurt, 70% ethanol).

Submitted in complete fulfillment for the degree of Doctor of Philosophy (Food Science and Technology), Durban University of Technology, Durban, South Africa, 2016. / Bambara groundnut (Vigna substerranea) is an indigenous legume of African origin which is currently experiencing a low level utilisation. It is tolerant to drought and can grow under poor soil conditions in which other lucrative crops such as groundnut cannot grow. Bambara is a good source of protein comparable to that of cowpea and slightly lower than soya bean. In order to assess the potential use of bambara protein as a functional ingredient in food systems and as an important ingredient for the formulation of therapeutic product, the knowledge of its protein composition, structure and functionality becomes important. The main goal of this thesis was to determine the composition and bioactive properties of bambara protein and its hydrolysates. Specifically, a comparative study was carried out on the protein content, yield and functional properties of protein concentrates prepared from three different bambara landraces using different extraction methods (Salt solubilisation and Acid precipitation). There was no significant difference in protein content, yield and functional properties of the landraces. However, the method of extraction had an influence on their physicochemical and functional properties. Acid precipitation produced bambara protein concentrates with high protein content and yield (79% and 52% respectively) when compared to salt solubilisation (protein content - 57% and yield - 25%). Protein concentrates prepared through salt solubilisation method exhibited better functional properties in terms of water absorption capacity, oil absorption capacity, foaming capacity, foaming stability and emulsion activities when compared to concentrates obtained through acid precipitation. Furthermore, the composition of bambara proteins produced through isoelectric precipitation was determined. SDS PAGE revealed four major bands; a broad band at 55 kDa which was analysed to be vicilin, two medium bands at 62 kDa and 80 kDa and a high molecular weight (HMW) protein at 141 kDa. Further investigation of bambara protein revealed vicilin (55 kDa) with two sub units as the major protein in bambara and this was also confirmed by the proteomic map. The proteomic map revealed acidic amino acids as the major protein of bambara which is characteristic of vicilin, the map also showed that there were differences in the number of spots across the landraces with 77 spots matching each other. Circular dichroism spectroscopy exhibited reductions in α-helix, and β-pleated sheet conformations as pH varies. In addition, the tertiary structures as observed from the near-UV CD spectra were also influenced by shifts in pH conditions. Differential scanning calorimetry thermograms showed two endothermic peaks at around 67 and 81oC respectively. These can be attributed to thermal denaturation of vicilin and the HMW protein. Subsequent studies used isolates from red bambara since the composition of the landraces were similar. Bambara protein isolate was subjected to enzymatic hydrolysis using three proteases (alcalase, pepsin and trypsin) to produce various bambara protein hydrolysates (BPHs). BPHs were investigated for antioxidant and antihypertensive activities. The in vitro structural and functional characteristics of bambara protein and its enzymatic protein hydrolysate revealed that bambara groundnut possessed antioxidant properties against a variety of physiologically relevant free radicals. High surface hydrophobicity and the molecular size of the peptide seem to be important for scavenging of hydroxyl radicals, ferric reducing power and metal chelation. BPHs and peptide fractions were able to scavenge DPPH radicals with greater affinity for smaller size. Less than 1 and 1-3 kDa pepsin fraction was able to scavenge DPPH radical more than glutathione, BPHs and its fractions scavenge ABTS•+ three folds than the isolate. Scavenging of superoxide radicals was generally weak except for 5-10 kDa peptide fractions. All BPHs inhibited linolenic acid oxidation with greater affinity for the lower molecular size peptide. BPHs showed potential antihypertensive properties because of the in vitro inhibition of activities of angiotensin converting enzyme (ACE) and renin inhibition. The molecular size had significant effect on the ACE inhibitory properties with low molecular weight peptide (<1 kDa) fractions exhibiting significantly higher (p<0.05) inhibitory activities. However, enzyme type had synergistic effects on renin inhibition with alcalase hydrolysate showing highest inhibition at 59% when compared to other hydrolysates and their membrane fractions. The fractions with <1 and 1-3 kDa peptides showed a higher potential as antihypertensive and antioxidant peptides. Based on this study, incorporation of bambara protein isolate as an ingredient may be useful for the manufacture of high quality food products. Likewise, the bambara protein hydrolysates, especially the <1 kDa and 1-3 kDa fraction represent a potential source of bioactive peptides in formulating functional foods and nutraceuticals. / D

Thesis (Master of Applied Sciences in Chemistry)--Cape Peninsula University of Technology, 2018. / Antimicrobial Peptides (AMPs) are short peptides of about 45 - 54 amino acids that exhibit antibacterial and antifungal activities. Plant defensin is a type of AMP in plants which belong to a family of cationic peptides with a characteristic 3D folding pattern held in place by four disulfide bridges. AMPs especially defensins have been identified to have a huge biotechnological potential and are being patented for many applications. The aim of this work was to clone an antimicrobial peptide from Vigna subterranea and characterise it with bioinformatics analysis. 4 sets of primers were synthesized according to the sequences of conserved regions in AMPs i.e. defensins from legumes like Vigna unguiculata, Vigna radiata, Cicer arietinum and Cajanus cajan, amongst others, which have defensins with only a few sequence differences. The primers were designated VsDef P1 to P4. Using Vigna subterranea total genomic DNA as a template, fragments of expected sizes were successfully amplified and cloned into the pDRIVE vector and used to transform Escherichia coli JM109 cells in each case. Representative clones were sequenced and analysed using BLAST from National Center for Biotechnology Information. However, only the VIG clone was shown to be a bona fide defensin (over 90% identity, E-value of 1ex102, 99% query coverage of the nucleotide sequence, compared to Vigna unguiculata defensin). Based on this high sequence identity, a new pair of primers VsDef P5 was designed based on the Vigna unguiculata defensin sequence to specifically amplify the complete Vigna subterranea defensin gene, hereafter called VsDef1. Attempts to clone VsDef1 were however unsuccessful, and evidence of clone deletion and insert re-arrangement of insert DNA was observed. Direct sequencing of the PCR product demonstrated that it was indeed the complete VsDef1 pre-protein, composed of 433 nucleotides. In silico translation and analysis showed that VsDef1 has an intron at position 105 − 259 of the nucleotide sequences and encodes for a 78 amino acid peptide. Phylogenetic analysis revealed to be similar to the sequence of the defensins for Vigna unguiculata (96%), Vigna radiata (95%), Vigna angularis (95%) and Phaseolus vulgaris (93%) on the NCBI database. The three - dimensional structure of the peptide was modelled with SWISS-MODEL expasy and the structure was found to include one α- and three β domains, similar to those of other defensins. The failure to identify VsDef1 clone in a V. subterranea library and the failure to recover its cDNA clone are consistent with the hypothesised toxicity of VsDef1 to Escherichia coli. It is suggested that a different host, such as yeast, should be used in the future. The VsDef1 mRNA levels in germinating V. subterranea seeds was however successfully investigated using real-time reverse transcription quantitative PCR. VsDef1 mRNA is present in both the testa and embryo of dry seed and will persist through the early stages of seedling growth. This demonstrates the importance of VsDef1 in fighting off infection during germination in order to ensure successful germination. It is therefore essential to characterise more antimicrobial peptides from V. subterranea. The diversity of AMPs and their patterns of expressed genes will enable understanding of complex regulatory networks, which will likely enable identifying of genes involved in diseases and new biological processes.

Thesis (MTech (Food Technology))--Cape Peninsula University of Technology, 2016. / The aim of this study was to evaluate Bambara groundnut (BGN) milk subjected to spray drying with a view to establish functional, nutritional and physical properties as an ingredient in BGN yoghurt production. BGN milk powder (BGNMP) was successfully produced employing the spray drying technology. Maltodextrin was used as the drying carrier to elevate total solids of BGNM prior to spray drying. There were three levels of maltodextrin (5, 10 and 15%) employed and 10% was ideal. The optimum spray drying parameters were estimated to be the following; inlet temperature (150oC), outlet temperature (74oC), air pressure (3 bars), flow rate (10% or 16mL/min), and air flow (42.9 m3/h). The functional properties evaluated revealed high water solubility capabilities, making BGNMP readily soluble in water, which is one of the most crucial aspects of milk powders. The water solubility index of BGNMP at all maltodextrin levels ranged from 85.15 to 90.25%. There was a significant (p < 0.05) difference amongst BGNMP (5, 10, and 15%) in colour parameters (lightness, yellowness, redness, chroma and hue angle). BGNMP indicated to have a red and yellow colour, but yellow was more dominant. The particle size and particle size distribution of BGNMP ranged from 86.13 to 162.35 μm and 84.04 to 157.0 μm, respectively and did not differ significantly (p > 0.05).

Thesis (Ph.D. (Zoology))--North-West University, Potchefstroom Campus, 2009.

HOST PLANT RESISTANCE AS A MANAGEMENT TOOL FOR DITYLENHUS AFRICANUS (MEMATODA: TYLENCHIDAE) ON GROUNDNUT {ARACHIS HYPOGAEA) Groundnut is an important cash crop both for commercial and smallscale farmers in South Africa. The effect of Ditylenchus africanus on groundnut is mainly qualitative, leading to downgrading of groundnut consignments. This nematode is difficult to control because of its high reproduction and damage potential. The objective of the study was to investigate the potential of host-plant resistance as an effective and economically-feasible alternative management tool for the control of D. africanus on groundnut. Selected groundnut genotypes were evaluated against D. africanus in microplot and field trials. PC254K1 and CG7 were identified as resistant to D. africanus. The resistance expressed by these two genotypes is sustainable under field conditions. The resistance expressed by PC254K1 is effective even at high population densities. This genotype consistently produced yields with a low UBS % at all nematode population levels. PC254K1 could therefore be used as a major source of resistance to D. africanus in the development of commercial cultivars. Although the breeding line PC287K5 also maintained low nematode numbers in some trials, its level of resistance does not seem to be as strong or as sustainable as that of PC254K1 or CG7. However, PC287K5 could still play an important role in the groundnut industry where lower D. africanus populations occur. The resistance expressed by PC254K1 is not transferred to leaf callus tissue of this genotype, confirming there is no short-cut for screening for resistance to D. africanus. The reproduction and damage potential of D. africanus populations from different geographically-isolated localities in the groundnut-production areas of South Africa was tested under controlled and semi-controlled conditions and were found to be similar to each other. Resistance of PC254K1 to all of the tested populations was confirmed. These results indicate that the presence of this resistant trait in a cultivar developed from PC254K1 should be sustainable over the whole groundnut-production area of South Africa. The absence of D. africanus from pod tissue of PC254K1 confirmed the genotype's resistance. The mechanism of resistance involved may be the inhibition of proper development of this nematode, preventing it to build up to damaging population levels. However, PC254K1 is not immune to this nematode since it does occur in small numbers on this genotype. The resistance trait in PC254K1 is seemingly governed by a number of genes, implying that it will be more durable under sustained pressure by D. africanus populations. Although markers associated with the resistance trait were mapped, they were not closely linked. Three putative qualitative trait loci (QTL's) were identified but markers associated with the resistance trait need to be refined and developed to be breeder-friendly in terms of marker-assisted selection. There are strong indications that CG7, which is a parent of PC254K1, may have more superior levels of resistance to D. africanus than PC254K1. The identification of markers closely associated with the resistance trait might, therefore, be more successful using CG7 in stead of PC254K1 / Thesis (Ph.D. (Zoology))--North-West University, Potchefstroom Campus, 2009.