Bambara groundnut (Vigna subterranean L.) is considered a good source of protein in some parts of sub Saharan African countries. Long cooking time of about three hours contributed to its limited consumption and utilisation. Micronisation is an infrared heating process. It can reduce the cooking time of pre-moisture conditioned legume small seeds size such as cowpea and lentil, but mostly tempering of seeds has been used as the pre-conditioning techniques. The resulting flour from the pre-conditioned micronised cowpea can reduce pasting viscosity and has potentials in food systems as an instant product. This study aimed at (1) determining the effects of micronisation of pre-soaked whole and dehulled bambara groundnut seeds on their cooking characteristics, (2) determining the effects of micronisation and dehulling treatment of pre-soaked bambara groundnut on physicochemical, microstructure and functional properties of the resulting flours and (3) determining the effects of micronisation of pre-soaked whole and dehulled bambara groundnut seeds on the viscosity, nutritional and health benefits of the cooked samples in order to produce a quick cooked bambara groundnut with functional, nutritional and health benefits. Micronisation (130 ºC) at a different time (0, 5, 10 and 15 min) was used to optimise the process for pre-soaked (53% moisture) bambara groundnuts. Micronisation (130 ºC) reduced cooking time of pre-soaked (53% moisture) bambara groundnut (whole and dehulled) following cooking. Micronisation reduced the 162 min cooking of raw bambara groundnut to 109, 83, 75 and 62 min when micronized for 0, 5, 10 and 15 min. Micronisation (53% moisture, 130 ºC) caused molecular changes such as solubilisation of pectin which was responsible for the disruption of the middle lamella and separation of parenchyma cell observed by light microscopy and scanning electron microscopy (SEM). It also caused disruption in the structure of starch granule, protein matrix in the cotyledon. These changes in seeds structure and molecular properties of starch, protein and pectin, facilitate water hydration rate and cell separation during cooking, leading to the shorter cooking time of the bambara groundnuts. Micronisation of pre-soaked (53% moisture) bambara groundnuts caused molecular changes such as partial starch gelatinisation and reduced protein solubility in the resulting flours. The changes in the starch and proteins modified the resulting flours functional properties such asincrease swelling of the resulting flours, while reducing the water solubility. The pasting viscosities of resulting flours of pre-soaked bambara groundnut reduced following micronisation due to the denatured protein matrix preventing embedded starch hydration, dispersibility and molecular entanglement during pasting.This was evident by light and confocal laser scanning microscopy (CLSM) that showed the aggregates of denatured protein matrix surrounding embedded pre-gelatinised starch granules increase with micronisation in the resulting flours and cooked soft porridge of bambara groundnut. Micronisation has an effect on the apparent viscosity, nutritional, bioactive compound such as phenolics and hence the antioxidant properties of cooked soft porridge of bambara groundnut. All cooked soft porridge of bambara groundnut exhibited a shear thinning behavior and micronised bambara groundnut had lower viscosity increased in the starch and protein digestibility of cooked soft porridge of bambara groundnut. It also increased the phenolic content and antioxidant properties of cooked soft porridge of whole bambara groundnut, but these were reduced in cooked soft porridge of dehulled bambara groundnut due to seed coat absence. Thus, micronisation of pre-soaked bambara groundnut (whole and dehulled) would contribute towards increased utilisation of bambara groundnut as well as improving house hold nutrition and health promoting properties.Micronisation of bambara groundnut has potential to produce a quick paste with low viscosity which depend on the pre-soaking and micronisation time of the bambara groundnut. Flours from micronised bambara groundnut can therefore be used as instant flour ingredient in food products. / Thesis (PhD)--University of Pretoria, 2016. / National Research Foundation (NRF) of South Africa / Food Science / PhD (Food Science) / Unrestricted

Made available in DSpace on 2017-07-10T17:37:31Z (GMT). No. of bitstreams: 1 Celso_Ari_Palagi.pdf: 1225111 bytes, checksum: 53c7b584eb8d2e2e9d1d9affdfb76833 (MD5) Previous issue date: 2004-03-29 / The culture of the Soya has great economic importance in the Brazilian agricultural scenery, from being that the production of seeds significantly to contribute importance with this process. Methods and tests of quality estimate of the seeds really have been showing their potential are avail large so, this work had purpose to seek a alternative methodology capable of to minimize the harm soak up during the realization the tests of the seeds germination standard. For so much, seeds coming from three places of production from South Brazil area, harvested the agricultural bearing 2001/02, of the cultivars CD 201, CD 202 and CD 210 were rated via middle of the tests: first couting of germination, tests germination standard of, percentile of plantule abnormal, tetrazolium germination, tetrazolium worth and emergency on soil flooring. The tests were done on two ages; the first on three months after harvest and the second on six months after harvest. On all tests parts of the seeds were pre-soaking prior of the realization of the same, the other party did follow the traditional methodology. The pre-soaking constituted in the setting of the seeds on ductile boxes (gerbox). On the screen steely inox containing 40 fl Oz milligram water, during a period of 24h the 25ºC, on camera of germination of type Mangelsdorf. After this period the seeds were analyzed in the diverse tests, according the prescribed in the Rules Parsing of Seeds. The sowing in the soil, for the evaluation of the emergency, went executing on hothouse covered with transparent sailcloth ductile like a tunnel. The contour experimental utilized was casually with four iterations. The Work were unfolded on two experiments conform origin the seeds; in the first went compared with the cultivars CD 201 and CD 202 and in the second analyzed only the CD 210. The results were, then, submitted to statistical parsing firstly, individually within on each epoch of evaluation on each place, and subsequent to proceeded the parsing conjoint considering two ages and the three places. The procured results permit to make conclusion that the results pre-soaking introduced 6% TPG seeds, only to the cultivar CD 202. To the three places, if nothing else one of the ages of realization tests. The responses positive of the pre-soaking of the seeds of cultivar CD 202 is compatible with the procured results in the test of tetrazolium/viability (1-5) e of emergency on soil. / A cultura da soja tem grande importância econômica no cenário agrícola brasileiro, sendo que a produção de sementes contribui significativamente com este processo. Métodos e testes de avaliação da qualidade das sementes que realmente expressem o seu potencial são de grande valia. Esta pesquisa teve por objetivo buscar uma metodologia alternativa capaz de minimizar os danos de embebição durante a realização do teste padrão de germinação das sementes. Para tanto, sementes provenientes de três locais de produção da região sul do Brasil, colhidas na safra agrícola 2001/02, dos cultivares CD 201, CD 202 e CD 210 foram avaliadas por meio dos testes: primeira contagem de germinação, teste padrão de germinação, percentual de plântulas anormais, tetrazólio germinação, tetrazólio vigor e emergência em solo. Os testes foram realizados em duas épocas; a primeira, três meses após a colheita (3 MAC) e a segunda, seis meses após a colheita (6 MAC). Em todos os testes subamostras das sementes foram pré-embebidas antes da realização dos mesmos e, a outra parte seguiu a metodologia tradicional. A pré-embebição consistiu na colocação das sementes em caixas plásticas sobre tela de aço inox, contendo 40 mL de água, por um período de 24h a 25oC, em câmara de germinação do tipo Mangelsdorf. As sementes foram analisadas nos diversos testes, conforme o prescrito nas Regras para Análise de Sementes. A semeadura no solo, para a avaliação da emergência, foi realizada em estufa coberta com lona plástica transparente - tipo túnel. O delineamento experimental utilizado foi o inteiramente casualizado com quatro repetições. O trabalho foi desdobrado em dois segmentos conforme a procedência das sementes; no primeiro foram comparados os cultivares CD 201 e CD 202 e no segundo analisou-se somente o CD 210. Os resultados foram, então, submetidos à análise estatística primeiramente, individual por época de avaliação em cada local, e posteriormente procedeu-se à análise conjunta considerando as duas épocas e os três locais. Os resultados obtidos permitiram concluir que a pré-embebição apresentou resultados superiores a 6% no TPG para as sementes do cultivar CD 202 dos três locais, em pelo menos uma das épocas de realização dos testes. A resposta positiva à pré-embebição das sementes do cultivar CD 202 é compatível com os resultados obtidos no teste de tetrazólio/viabilidade (1-5) e de emergência em solo. O cultivar CD 210 apresentou resultados significativos à pré-embebição nos testes de primeira contagem de germinação e TPG, somente para as sementes de Campo Mourão e Cascavel.