CAPES; Fundação Araucária / Distribuída e cultivada em vários países, a batata-doce (Ipomoea batatas L. Lam.) é um alimento de suma importância na dieta diária da população, principalmente no continente asiático, o qual detém a maior parcela de sua produção. Essa raiz tuberosa é rica em nutrientes e fonte de energia. Além disso, algumas cultivares possuem em sua composição compostos bioativos como antocianinas, carotenoides e polifenóis, os quais apresentam atividade antioxidante e podem contribuir beneficamente para a manutenção do organismo humano. Nesse sentido, o presente trabalho objetivou a análise biométrica, a caracterização físico-química, a quantificação do total de compostos bioativos, o potencial antioxidante e o uso da tecnologia de imagem digital para estabelecer um comparativo entre o conteúdo de cor e as características físico-químicas, de novas cultivares de batatas-doces. Foram obtidas junto a Epagri-EEI/SC, amostras das raízes tuberosas das cultivares de batatas-doces denominadas SCS370 Luiza, SCS371 Katiy, SCS372 Marina, Beauregard, Uruguaia e Americana, sendo que cada variedade foi avaliada na condição in natura e liofilizada (lote um (LT1) e lote dois (LT2), respectivamente). Realizaram-se as medidas em triplicata dos parâmetros de atividade de água, acidez titulável, umidade, cinzas, proteínas, lipídeos, teor de vitamina C, açúcares totais e redutores, conteúdo total de fenólicos, flavonoides, antocianinas e carotenoides, o potencial antioxidante (ABTS+ e FRAP), cor instrumental nos espaço de cor CIE L*a*b*, CIE L*C*h° e XYZ, e imagens digitais, as quais foram obtidas por câmara digital e processadas em software desenvolvido exclusivamente para o estudo das imagens digitais de batatas-doces. O teor de minerais Cu (Cobre), Fe (Ferro), Zn (Zinco), Mn (Manganês), Na (Sódio), K (Potássio), Ca (Cálcio), Mg (Magnésio), P (Fósforo), Co (Cobalto), Cd (Cádmio), Cr (Cromo), Pb (Chumbo) resultou de uma única determinação. Outras características foram avaliadas em função de: Espectroscopia na Região de Absorção no Infravermelho, Difratometria de Raios-X, Análise por Termogravimetria e Microscopia de Varredura Eletrônica. As características resultantes para as diferentes coordenadas de cor (L*, a*, b*; C*, h°, X, Y, Z) das batatas-doces, demonstraram ser influenciadas pelas propriedades intrínsecas de cada cultivar, porém os resultados médios de cor estabeleceram uniformidades para as amostras entre seus lotes. O comparativo entre as coordenadas de cor instrumental e a análise dos diferentes canais de cor das imagens digitais (RGB, XYZ, LUV, HSV) indicaram ser possível estabelecer uma correlação entre as cultivares liofilizadas e suas imagens digitais. O teor de umidade para todas as cultivares foi característico para batatas-doces, sendo o maior valor para a cultivar (cv.) Uruguaia LT2 (83,93±0,04 %) in natura e cv. Americana LT2 (3,27±0,15 %) na condição liofilizada. A cv. SCS370 Luiza LT2 nas amostras in natura (0,94±00), exibiu o maior valor para atividade de água (Aw) sendo que todas as amostras liofilizadas apresentaram valor foi inferior a 0,15. Os valores de acidez titulável variaram para as amostras in natura de 2,77±0,08 % (cv. Beauregard LT1) a 1,51±0,07 % (cv. SCS371 Katiy LT2), e para as amostras liofilizadas de 1,86±0,09 % (cv. Americana LT2) a 0,52±0,07 % (cv. SCS371 Katiy LT1). Para o conteúdo de 9 cinzas, houve variação para as amostras in natura de 1,19±0,04 % (cv. SCS370 Luiza LT1) a 0,04%±0,00 % (cv. SCS372 Marina LT2), sendo que para as amostras liofilizadas o teor de cinzas foi superior. O conteúdo de proteínas variou entre 2,80±0,18 % (cv. Americana LT2) a 0,49±0,21 % (cv. SCS371 Katiy LT1) para as amostras in natura, e 8,20±0,09 % (cv. Americana LT2) e 3,14±0,57 % (cv. SCS370 Luiza LT1) para as amostras liofilizadas. As amostras de batatas-doces exibiram baixos valores para lipídios totais e não diferiram estatísticamente entre as cultivares. Os açúcares totais variaram entre 32,85±0,07 % (cv. SCS372 Marina LT2) e 16,99±0,044 % (cv. SCS371 Katiy LT1). Já para vitamina C, o maior conteúdo foi observado para cv. SCS370 Luiza LT2 (57,17±4,32 %) sendo o menor para cv. SCS372 Marina LT1 (17,00±1,00 %) para as amostras in natura, e entre as amostras liofilizadas o maior valor foi novamente observado para cv. SCS370 Luiza LT2 (69,78±2,20 %). Todas as cultivares de batatas-doces apresentaram conteúdo satisfatório para os minerais avaliados, com destaque para o teor de macrominerais das cv. Beauregard LT1 e SCS370 Luiza LT1. A avaliação do conteúdo total de bioativos indicou alta variabilidade entre as cultivares. O maior valor para fenólicos totais foi observado para a cv. SCS370 Luiza LT2 (3311,10±57,17 mg EAG.100g-1), e o menor valor para cv. Americana LT2 (102,62±1,22 mg EAG.100g-1), sendo estas as mesmas amostras a apresentarem o maior (148,45±1,31 mgCE.100g-1, cv. SCS370 Luiza LT2) e o menor (2,18±0,10 mgCE.100g-1, cv. Americana) conteúdo de flavonoides totais. Já para antocianinas totais, o maior valor foi observado novamente para a cv. SCS370 Luiza LT2 (155,30±6,48 mg.100g-1) e o menor valor para cv. SCS372 Marina LT2 (1,28±1,24 mg.100g-1). Os resultados para carotenoides totais variaram entre 34,04±0,66 mg.100g-1 (cv. Beauregard LT1) e 0,63±0,06 mg.100g-1 (cv.SCS371 Katiy LT2). A atividade antioxidante das amostras de batatas-doces foi satisfatória, sendo que os resultados pela metodologia de ABTS+ variaram entre 466,85±1,96 mM Trolox.100g-1 (cv. SCS370 Luiza LT2) e 128,26±4,40 mM Trolox.100g-1 (cv. SCS372 Marina LT1). Pela metodologia FRAP, a maior atividade antioxidante foi novamente observada para cv. SCS370 Luiza LT2 (734,19±63,09 mM FeSO4.100g-1), sendo a menor atividade antioxidante da cv. Beauregard LT1 (18,42±1,28 mM FeSO4.100g-1). A análise de difração de Raios X possibilitou uma tentativa de atribuição de cristalinidade das amostras liofilizadas de batata-doce, sendo classificadas como Tipo A e Tipo B. A análise de espectroscopia de absorção por infravermelho (FTIR) revelou semelhanças de grupos funcionais quando comparamos as diferentes cultivares. A análise termogravimétrica indicou os limites da resistência térmica das amostras. A microscopia eletrônica de varredura ilustrou as estruturas lamelares, os bloquetes, e a geometria dos grânulos presentes nas amostras de batatas-doces. Em função dos resultados encontrados, pode-se afirmar que as novas cultivares de batatas-doces apresentam valor econômico e nutricional agregado, tornando-se uma alternativa de cultivo para os pequenos agricultores, aumentando assim sua disponibilidade no comércio varejista, bem como sua utilização como matéria-prima industrial. / Sweet potato (Ipomoea batatas L. Lam.) is largely cultivated and greatly consumed as part of the regular diet, mainly in Asian continent, that is it’s the major producer. This tuber crop is rich in nutrient and energy source. Thus, some cultivars have bioactive compounds such as anthocyanins, carotenoids and polyphenols, which have antioxidant activity and can be beneficial to the body maintenance. In this sense, the objective of this work is to analyze the biometric, physical chemistry, quantification of bioactive compounds, antioxidant activity, and analyze digital image analysis of new sweet potato cultivars to do a comparative with their colour and physical chemistry composition. We received from Epagri-EEI/SC samples of sweet potato tuber roots named SCS370 Luiza, SCS371 Katiy, SCS372 Marina, Beauregard, Uruguaia and Americana being that cultivars analyzed in natura and lyophilized condition from batch one (LT1) and batch two (LT2). All analyses were performed in triplicate to water activity, titratable acidity, humidity, ashes, protein, lipids, vitamin C, total and reducers carbohydrates, total phenolic, flavonoids, anthocyanins and carotenoids, antioxidant activity (ABTS+ and FRAP), colour by coordinates CIE L*a*b*, CIE L*C*h° and XYZ, and digital images that was obtained by digital camera and processed with exclusive developed software to analyze that images. Mineral composition evaluation of Cu (Copper), Fe (Iron), Zn (Zinc), Mn (Manganese), Na (Sodium), K (Potassium), Ca (Calcium), Mg (Magnesium), P (Phosphorus), Co (Cobalt), Cd (Cadmium), Cr (Cromium), Pb (Lead) was performed by once. Another set of characteristics was evaluated by Infra-Red Spectroscopy with Fourier Transformed, X Rays Diffractometry, Thermogravimetric Analysis and Scanning Electron Microscopy. The sweet potato colour results from different coordinates (L*, a*, b*; C*, h°, X, Y, Z) showed be influenced by cultivar intrinsic properties but the standard results establish sample uniformities to different batches. Comparison between colour coordinates and digital images colour channels (RGB, XYZ, LUV, HSV, HLS) showed to be possible to establish a correlation between the lyophilized samples and they digital images. Sweet potatoes humidity quantification showed high value to cultivar (cv.) Uruguaia LT2 (83.93±0.04 %) in natura and lyophilized cv. Americana LT2 (3.27±0.15 %). The cv. SCS370 Luiza LT2 in natura (0.94±00) showed the highest value to water activity, and all lyophilized samples showed low value as 0.15. Titratable acidity values ranges for in natura samples by 2.77±0.08 % (cv. Beauregard LT1) to 1.51±0.07 % (cv. SCS371 Katiy LT2), and 1.86±0.09 % (cv. Americana LT2) to 0.52±0.07 % (cv. SCS371 Katiy LT1) for lyophilized samples. Ashes content showed variation for in natura samples by 1.19±0.04 % (cv. SCS370 Luiza LT1) to 0.04%±0.00 % (cv. SCS372 Marina LT2), but lyophilized samples showed highest ashes values then in natura. Protein content ranges by 2.80±0.18 % (cv. Americana LT2) to 0.49±0.21 % (cv. SCS371 Katiy LT1) for in natura samples, and 8.20±0.09 % (cv. Americana LT2) to 3.14±0.57 % (cv. SCS370 Luiza LT1) for lyophilized samples. Sweet potatoes cultivars exhibited low values to total lipids and their values do not shows statistical variation. Total carbohydrates composition ranges between 32.85±0.07 % (cv. SCS372 Marina LT2) 11 and 16.99±0.044 % (cv. SCS371 Katiy LT1). The vitamin C content was highest to cv. SCS370 Luiza LT2 (57.17±4.32 %) and lowest to cv. SCS372 Marina LT1 (17.00±1.00 %) for in natura samples, but cv. SCS370 Luiza LT2 (69.78±2.20 %) shows the highest value for lyophilized samples. All sweet potatoes cultivars showed great content for the evaluated minerals with emphasis for the macrominerals content of cv. Beauregard LT1 and SCS370 Luiza LT1. The bioactive compound shows high variation between sweet potatoes cultivars. The phenolic highest values was observed to cv. SCS370 Luiza LT2 (3311.10±57.17 mg GAE.100g-1), and the lowest value was cv. Americana LT2 (102.62±1.22 mg GAE.100g-1), and those same samples showed the highest (148.45±1.31 mg CE.100g-1, cv. SCS370 Luiza LT2) and lowest (2.18±0.10 mgCE.100g-1, cv. Americana) total flavonoid composition. The total anthocyanins composition showed again highest value to cv. SCS370 Luiza LT2 (155.30±6.48 mg.100g-1) and lowest value to cv. SCS372 Marina LT2 (1.28±1.24 mg.100g-1). Total carotenoids result ranges by 34.04±0.66 mg.100g-1 (cv. Beauregard LT1) to 0.63±0.06 mg.100g-1 (cv.SCS371 Katiy LT2). The sweet potatoes antioxidant activity was great and the results by ABTS+ test ranges by 466.85±1.96 mM Trolox.100g-1 (cv. SCS370 Luiza LT2) to 128.26±4.40 mM Trolox.100g-1 (cv. SCS372 Marina LT1). By the FRAP teste, the highest antioxidant activity was again observed to cv. SCS370 Luiza LT2 (734.19±63.09 mM FeSO4.100g-1), and the lowest antioxidant activity was cv. Beauregard LT1 (18.42±1.28 mM FeSO4.100g-1). The X Rays diffractometry analysis enabled an attempt to assign the lyophilized sampled crystallinity that was considered by Type A and Type B. The infrared spectroscopy analyses showed similarity to the functional groups when compared the sweet potato samples among different batches. Thermogravimetric analysis indicates the sample thermal resistance. The electron microscopy scanning shows the lamella structure, blocks, and granular geometrical structure in the samples. Having in mind the results obtained, it is possible to support the new cultivars of sweet potatoes have an economic and nutritional added value, as they become an alternative of cultivation for small farmers, increasing their availability in the retail trade, as well as their use as industrial feedstock.

CAPES; Fundação Araucária / Distribuída e cultivada em vários países, a batata-doce (Ipomoea batatas L. Lam.) é um alimento de suma importância na dieta diária da população, principalmente no continente asiático, o qual detém a maior parcela de sua produção. Essa raiz tuberosa é rica em nutrientes e fonte de energia. Além disso, algumas cultivares possuem em sua composição compostos bioativos como antocianinas, carotenoides e polifenóis, os quais apresentam atividade antioxidante e podem contribuir beneficamente para a manutenção do organismo humano. Nesse sentido, o presente trabalho objetivou a análise biométrica, a caracterização físico-química, a quantificação do total de compostos bioativos, o potencial antioxidante e o uso da tecnologia de imagem digital para estabelecer um comparativo entre o conteúdo de cor e as características físico-químicas, de novas cultivares de batatas-doces. Foram obtidas junto a Epagri-EEI/SC, amostras das raízes tuberosas das cultivares de batatas-doces denominadas SCS370 Luiza, SCS371 Katiy, SCS372 Marina, Beauregard, Uruguaia e Americana, sendo que cada variedade foi avaliada na condição in natura e liofilizada (lote um (LT1) e lote dois (LT2), respectivamente). Realizaram-se as medidas em triplicata dos parâmetros de atividade de água, acidez titulável, umidade, cinzas, proteínas, lipídeos, teor de vitamina C, açúcares totais e redutores, conteúdo total de fenólicos, flavonoides, antocianinas e carotenoides, o potencial antioxidante (ABTS+ e FRAP), cor instrumental nos espaço de cor CIE L*a*b*, CIE L*C*h° e XYZ, e imagens digitais, as quais foram obtidas por câmara digital e processadas em software desenvolvido exclusivamente para o estudo das imagens digitais de batatas-doces. O teor de minerais Cu (Cobre), Fe (Ferro), Zn (Zinco), Mn (Manganês), Na (Sódio), K (Potássio), Ca (Cálcio), Mg (Magnésio), P (Fósforo), Co (Cobalto), Cd (Cádmio), Cr (Cromo), Pb (Chumbo) resultou de uma única determinação. Outras características foram avaliadas em função de: Espectroscopia na Região de Absorção no Infravermelho, Difratometria de Raios-X, Análise por Termogravimetria e Microscopia de Varredura Eletrônica. As características resultantes para as diferentes coordenadas de cor (L*, a*, b*; C*, h°, X, Y, Z) das batatas-doces, demonstraram ser influenciadas pelas propriedades intrínsecas de cada cultivar, porém os resultados médios de cor estabeleceram uniformidades para as amostras entre seus lotes. O comparativo entre as coordenadas de cor instrumental e a análise dos diferentes canais de cor das imagens digitais (RGB, XYZ, LUV, HSV) indicaram ser possível estabelecer uma correlação entre as cultivares liofilizadas e suas imagens digitais. O teor de umidade para todas as cultivares foi característico para batatas-doces, sendo o maior valor para a cultivar (cv.) Uruguaia LT2 (83,93±0,04 %) in natura e cv. Americana LT2 (3,27±0,15 %) na condição liofilizada. A cv. SCS370 Luiza LT2 nas amostras in natura (0,94±00), exibiu o maior valor para atividade de água (Aw) sendo que todas as amostras liofilizadas apresentaram valor foi inferior a 0,15. Os valores de acidez titulável variaram para as amostras in natura de 2,77±0,08 % (cv. Beauregard LT1) a 1,51±0,07 % (cv. SCS371 Katiy LT2), e para as amostras liofilizadas de 1,86±0,09 % (cv. Americana LT2) a 0,52±0,07 % (cv. SCS371 Katiy LT1). Para o conteúdo de 9 cinzas, houve variação para as amostras in natura de 1,19±0,04 % (cv. SCS370 Luiza LT1) a 0,04%±0,00 % (cv. SCS372 Marina LT2), sendo que para as amostras liofilizadas o teor de cinzas foi superior. O conteúdo de proteínas variou entre 2,80±0,18 % (cv. Americana LT2) a 0,49±0,21 % (cv. SCS371 Katiy LT1) para as amostras in natura, e 8,20±0,09 % (cv. Americana LT2) e 3,14±0,57 % (cv. SCS370 Luiza LT1) para as amostras liofilizadas. As amostras de batatas-doces exibiram baixos valores para lipídios totais e não diferiram estatísticamente entre as cultivares. Os açúcares totais variaram entre 32,85±0,07 % (cv. SCS372 Marina LT2) e 16,99±0,044 % (cv. SCS371 Katiy LT1). Já para vitamina C, o maior conteúdo foi observado para cv. SCS370 Luiza LT2 (57,17±4,32 %) sendo o menor para cv. SCS372 Marina LT1 (17,00±1,00 %) para as amostras in natura, e entre as amostras liofilizadas o maior valor foi novamente observado para cv. SCS370 Luiza LT2 (69,78±2,20 %). Todas as cultivares de batatas-doces apresentaram conteúdo satisfatório para os minerais avaliados, com destaque para o teor de macrominerais das cv. Beauregard LT1 e SCS370 Luiza LT1. A avaliação do conteúdo total de bioativos indicou alta variabilidade entre as cultivares. O maior valor para fenólicos totais foi observado para a cv. SCS370 Luiza LT2 (3311,10±57,17 mg EAG.100g-1), e o menor valor para cv. Americana LT2 (102,62±1,22 mg EAG.100g-1), sendo estas as mesmas amostras a apresentarem o maior (148,45±1,31 mgCE.100g-1, cv. SCS370 Luiza LT2) e o menor (2,18±0,10 mgCE.100g-1, cv. Americana) conteúdo de flavonoides totais. Já para antocianinas totais, o maior valor foi observado novamente para a cv. SCS370 Luiza LT2 (155,30±6,48 mg.100g-1) e o menor valor para cv. SCS372 Marina LT2 (1,28±1,24 mg.100g-1). Os resultados para carotenoides totais variaram entre 34,04±0,66 mg.100g-1 (cv. Beauregard LT1) e 0,63±0,06 mg.100g-1 (cv.SCS371 Katiy LT2). A atividade antioxidante das amostras de batatas-doces foi satisfatória, sendo que os resultados pela metodologia de ABTS+ variaram entre 466,85±1,96 mM Trolox.100g-1 (cv. SCS370 Luiza LT2) e 128,26±4,40 mM Trolox.100g-1 (cv. SCS372 Marina LT1). Pela metodologia FRAP, a maior atividade antioxidante foi novamente observada para cv. SCS370 Luiza LT2 (734,19±63,09 mM FeSO4.100g-1), sendo a menor atividade antioxidante da cv. Beauregard LT1 (18,42±1,28 mM FeSO4.100g-1). A análise de difração de Raios X possibilitou uma tentativa de atribuição de cristalinidade das amostras liofilizadas de batata-doce, sendo classificadas como Tipo A e Tipo B. A análise de espectroscopia de absorção por infravermelho (FTIR) revelou semelhanças de grupos funcionais quando comparamos as diferentes cultivares. A análise termogravimétrica indicou os limites da resistência térmica das amostras. A microscopia eletrônica de varredura ilustrou as estruturas lamelares, os bloquetes, e a geometria dos grânulos presentes nas amostras de batatas-doces. Em função dos resultados encontrados, pode-se afirmar que as novas cultivares de batatas-doces apresentam valor econômico e nutricional agregado, tornando-se uma alternativa de cultivo para os pequenos agricultores, aumentando assim sua disponibilidade no comércio varejista, bem como sua utilização como matéria-prima industrial. / Sweet potato (Ipomoea batatas L. Lam.) is largely cultivated and greatly consumed as part of the regular diet, mainly in Asian continent, that is it’s the major producer. This tuber crop is rich in nutrient and energy source. Thus, some cultivars have bioactive compounds such as anthocyanins, carotenoids and polyphenols, which have antioxidant activity and can be beneficial to the body maintenance. In this sense, the objective of this work is to analyze the biometric, physical chemistry, quantification of bioactive compounds, antioxidant activity, and analyze digital image analysis of new sweet potato cultivars to do a comparative with their colour and physical chemistry composition. We received from Epagri-EEI/SC samples of sweet potato tuber roots named SCS370 Luiza, SCS371 Katiy, SCS372 Marina, Beauregard, Uruguaia and Americana being that cultivars analyzed in natura and lyophilized condition from batch one (LT1) and batch two (LT2). All analyses were performed in triplicate to water activity, titratable acidity, humidity, ashes, protein, lipids, vitamin C, total and reducers carbohydrates, total phenolic, flavonoids, anthocyanins and carotenoids, antioxidant activity (ABTS+ and FRAP), colour by coordinates CIE L*a*b*, CIE L*C*h° and XYZ, and digital images that was obtained by digital camera and processed with exclusive developed software to analyze that images. Mineral composition evaluation of Cu (Copper), Fe (Iron), Zn (Zinc), Mn (Manganese), Na (Sodium), K (Potassium), Ca (Calcium), Mg (Magnesium), P (Phosphorus), Co (Cobalt), Cd (Cadmium), Cr (Cromium), Pb (Lead) was performed by once. Another set of characteristics was evaluated by Infra-Red Spectroscopy with Fourier Transformed, X Rays Diffractometry, Thermogravimetric Analysis and Scanning Electron Microscopy. The sweet potato colour results from different coordinates (L*, a*, b*; C*, h°, X, Y, Z) showed be influenced by cultivar intrinsic properties but the standard results establish sample uniformities to different batches. Comparison between colour coordinates and digital images colour channels (RGB, XYZ, LUV, HSV, HLS) showed to be possible to establish a correlation between the lyophilized samples and they digital images. Sweet potatoes humidity quantification showed high value to cultivar (cv.) Uruguaia LT2 (83.93±0.04 %) in natura and lyophilized cv. Americana LT2 (3.27±0.15 %). The cv. SCS370 Luiza LT2 in natura (0.94±00) showed the highest value to water activity, and all lyophilized samples showed low value as 0.15. Titratable acidity values ranges for in natura samples by 2.77±0.08 % (cv. Beauregard LT1) to 1.51±0.07 % (cv. SCS371 Katiy LT2), and 1.86±0.09 % (cv. Americana LT2) to 0.52±0.07 % (cv. SCS371 Katiy LT1) for lyophilized samples. Ashes content showed variation for in natura samples by 1.19±0.04 % (cv. SCS370 Luiza LT1) to 0.04%±0.00 % (cv. SCS372 Marina LT2), but lyophilized samples showed highest ashes values then in natura. Protein content ranges by 2.80±0.18 % (cv. Americana LT2) to 0.49±0.21 % (cv. SCS371 Katiy LT1) for in natura samples, and 8.20±0.09 % (cv. Americana LT2) to 3.14±0.57 % (cv. SCS370 Luiza LT1) for lyophilized samples. Sweet potatoes cultivars exhibited low values to total lipids and their values do not shows statistical variation. Total carbohydrates composition ranges between 32.85±0.07 % (cv. SCS372 Marina LT2) 11 and 16.99±0.044 % (cv. SCS371 Katiy LT1). The vitamin C content was highest to cv. SCS370 Luiza LT2 (57.17±4.32 %) and lowest to cv. SCS372 Marina LT1 (17.00±1.00 %) for in natura samples, but cv. SCS370 Luiza LT2 (69.78±2.20 %) shows the highest value for lyophilized samples. All sweet potatoes cultivars showed great content for the evaluated minerals with emphasis for the macrominerals content of cv. Beauregard LT1 and SCS370 Luiza LT1. The bioactive compound shows high variation between sweet potatoes cultivars. The phenolic highest values was observed to cv. SCS370 Luiza LT2 (3311.10±57.17 mg GAE.100g-1), and the lowest value was cv. Americana LT2 (102.62±1.22 mg GAE.100g-1), and those same samples showed the highest (148.45±1.31 mg CE.100g-1, cv. SCS370 Luiza LT2) and lowest (2.18±0.10 mgCE.100g-1, cv. Americana) total flavonoid composition. The total anthocyanins composition showed again highest value to cv. SCS370 Luiza LT2 (155.30±6.48 mg.100g-1) and lowest value to cv. SCS372 Marina LT2 (1.28±1.24 mg.100g-1). Total carotenoids result ranges by 34.04±0.66 mg.100g-1 (cv. Beauregard LT1) to 0.63±0.06 mg.100g-1 (cv.SCS371 Katiy LT2). The sweet potatoes antioxidant activity was great and the results by ABTS+ test ranges by 466.85±1.96 mM Trolox.100g-1 (cv. SCS370 Luiza LT2) to 128.26±4.40 mM Trolox.100g-1 (cv. SCS372 Marina LT1). By the FRAP teste, the highest antioxidant activity was again observed to cv. SCS370 Luiza LT2 (734.19±63.09 mM FeSO4.100g-1), and the lowest antioxidant activity was cv. Beauregard LT1 (18.42±1.28 mM FeSO4.100g-1). The X Rays diffractometry analysis enabled an attempt to assign the lyophilized sampled crystallinity that was considered by Type A and Type B. The infrared spectroscopy analyses showed similarity to the functional groups when compared the sweet potato samples among different batches. Thermogravimetric analysis indicates the sample thermal resistance. The electron microscopy scanning shows the lamella structure, blocks, and granular geometrical structure in the samples. Having in mind the results obtained, it is possible to support the new cultivars of sweet potatoes have an economic and nutritional added value, as they become an alternative of cultivation for small farmers, increasing their availability in the retail trade, as well as their use as industrial feedstock.

Experimentos com vista à avaliação das propriedades físico-quimica, fitoquímicas e biológica, bem como a sua estabilidade, em raízes tuberosas maduras, caules e folhas jovens de duas cultivares, RBS Amélia e RBS Cuia, e dois acessos de Ipomoea batatas, um de polpa púrpura com manchas brancas (C) e outro de polpa púrpura (D), cultivados ecologicamente e em condições de sequeiro na Horta Comunitária de Lomba do Pinheiro (30º 06’ 46’’ S; 51º 06’ 34’’ O) no Município de Porto alegre, RS no período de 2013 a 2015 foram efetuados nos laboratórios de Higiene, Qualidade e Microbiologia de alimentos e de Química e Bromatologia do Instituto de Ciência e Tecnologia de Alimento (ICTA) da Universidade Federal do Rio Grande do Sul (UFRGS). A avaliação quantita-tiva das propriedades físico-químicas e fitoquímicas seguiu os métodos descritos no Manual das Normas Técnicas para Determinação das Propriedades Físico-químicas em alimentos do Instituto Adolfo Lutz. O teor de polifenóis totais foi determinado pelo método de Folin & Ciocalteu, o con-teúdo de antocianinas pelo método de pH diferencial, os flavonoides, taninos e vitamina C avalia-dos por métodos espectrofotométricos. A atividade biológica consistiu na determinação das pro-priedades antioxidantes dos materiais usando o método fotocolorimétrico in vitro, empregando o radical livre estável 2,2-difenil-1-picrilhidrazila (DPPH) e na avaliação da atividade antimicrobi-ana, expressa como intensidade de atividade de inibição bacteriana (IINIB) e intensidade de ativi-dade de inativação bacteriana (IINAB), usando sistema de tubos múltiplos frente a diferentes con-centrações de Salmonella Enteritidis (ATCC 11076), Enterococcus faecalis (ATCC 19433), Es-cherichia coli (ATCC 11229) e Staphylococcus aureus (ATCC 25923). Foi igualmente analisada a estabilidade físico-química, fitoquímica e biológica das raízes tuberosas, caules e folhas estoca-dos a temperatura ambiente por períodos de 90, 180 e 270 dias, através da mensuração e avaliação das concentrações dos componentes físico-químicos, fitoquímicos e atividade biológica naqueles pontos de estocagem, Foram encontrados teores de proteínas variando de 10,5 a 26,3%, carboidra-tos totais oscilando de 15,7 a 61,1% com valores altos observados na cultiva RBS Amélia. Maiores teores de fenólicos totais e antocianinas foram observados em acessos de polpa púrpura com valo-res até 709,3 e 78,7mg/100g, respectivamente. Elevada atividade antioxidante foi também verifi-cada na maioria dos extratos testados que, igualmente, evidenciaram atividade antibacteriana frente a todos os inóculos testados ainda que a sua intensidade tenha sido diferente. Porém, nenhuma atividade antibacteriana foi verificada em extratos preparados com base no calor, quais sejam in-fusão e decocção. A estabilidade das propriedades de todos esses materiais foi presenciada embora algumas características tenham reduzido seus teores aos 270 dias de estocagem. O trabalho conclui que as raízes tuberosas, caules e folhas das cultivares RBS Amélia e RBS Cuia e dos acessos de batata-doce estudados se constituem em hortaliças vegetais com alto potencial físico-químico, fi-toquímico e biológico, a avaliar pelos altos teores de carboidratos totais, considerável concentração de proteínas, elevados valores de polifenóis totais e, ou antocianinas, principalmente nos acessos de polpa púrpura. Os mesmos materiais têm um indicativo de atividade antioxidante e de atividade antibacteriana seletiva frente a Salmonella Enteritidis (ATCC 11076), Enterococcus faecalis (ATCC 19433), Escherichia coli (ATCC 11229) e Staphylococcus aureus (ATCC 25923). Figuram-se, portanto, como uma excelente fonte de proteína, carboidratos e de compostos fenólicos relativamente estável por período de 270 dias de estocagem a temperatura ambiente, tornando-se importante na segurança alimentar e nutricional, saúde e bem-estar social. / Experiments for the evaluation of the physic-chemical, phytochemical and biological properties, and their stability in mature tuber roots, young stems and leaves of two cultivars, RBS Amelia and RBS Cuia and of two accessions of Ipomoea batatas, one having purple fleshed tuber roots with white spots (C) and another purple fleshed tuber (D), grown ecologically in “ Horta Comunitária da Lomba do Pinheiro (30º 06' 46'' S, 51° 06' 34'' O), Porto alegre, RS from the period of 2013 to 2015 were perfomed in the Hygiene, Quality and Microbiology and Food Chemistry laboratories of the Institute of Science and food Technology (ICTA), Federal University of Rio Grande do Sul (UFRGS). The quantitative assessment of physicochemical and phytochemical properties followed the described methods in the Manual of Technical Standards for Determination of Physical and Chemical Properties, Institute Adolfo Lutz. The total polyphenol content was determined by the Folin & Ciocalteu method, the content of anthocyanins at pH differential method, flavonoids, tan-nins, and vitamin C evaluated by spectrophotometric methods. Biological activity was analysed evaluated by determinating antioxidant properties of materials using fotocolorimétrico in vitro method, using the stable free radical 2,2-diphenyl-1-picrilhidrazila (DPPH) and also by evaluating antimicrobial activity, expressed as intensity of bacterial inhibition activity (IINIB) and intensity of bacterial inactivation activity (IINAB) using multiple tube system against different concentra-tions of Salmonella enteritidis (ATCC 11076), Enterococcus faecalis (ATCC 19433), Escherichia coli (ATCC 11229) and Staphylococcus aureus (ATCC 25923). It was also analyzed the physical and chemical, phytochemical and biological stability of tuber roots, stems and leaves stored at room temperature for periods of 90, 180 and 270 days, through the measurement and assessment of con-centrations of physico-chemical components, phytochemicals and biological activity on those points of storage. Protein levels were found ranging from 10.5 to 26.3%, total carbohydrates rang-ing from 15.7 to 61.1% with higher values observed in the RBS Amelia cultivar. Higher total phe-nolic content and anthocyanins were found in the purple fleshed roos, with values of up to 709.3 and 78,7mg / 100g, respectively. High anti-oxidant activity was also observed in most of the tested extracts which also showed antibacterial activity against all inocula tested, although its intensity was different. However, no antibacterial activity was detected in extracts prepared by heat, namely infusion and decoction. The stability of the properties of all materials was attended although some features have reduced its contents to 270 days of storage. The paper concludes that the tuber roots, stems and leaves of the RBS Amélia and RBS Cuia cultivars and sweet potato accessions studied constitute vegetables with high physical-chemical, phytochemical and biological potential, accord-ing to the high levels of total carbohidrates, considerable protein concentration, high total polyphe-nol values, or anthocyanins, mainly in pupuple fleshed roots accesses. The same materials have an indicative of antioxidant activity and selective antibacterial activity against Salmonella enteritidis (ATCC 11076), Enterococcus faecalis (ATCC 19433), Escherichia coli (ATCC 11229) and Sta-Staphylococcus aureus (ATCC 25923). Therefore, this specie can be seen as an excellent source of protein, carbohydrates and relatively stable phenolic compounds for a period of 270 days of storage at room temperature, making it important for food security and nutrition, health and social welfare.

Due to the need to define a dose of nitrogen agronomic and economically suitable for the cultivation of sweet potato in the state of Sergipe. The aim of this study was to evaluate the root yield, starch and ethanol in sweet potato clones analyzed from nitrogen. The study was conducted between the months of March and August 2012 at the Experimental Farm |Campus Rural da UFS|, located in the municipality of São Cristóvão, Sergipe, Brazil. We used a randomized complete block randomized in a 5x3 factorial design with three replications, testing five N rates (0, 30, 60, 120 and 240 kg ha-1), using as a source of N as urea (45 % N), and three clones of sweet potato (Brazlândia Branca, IPB-075 and IPB-149). The commercial cultivar Brazlândia Branca was considered as a witness. The crop was harvested at 150 days after planting, by quantifying the total biomass productivity and roots, the dry matter content of the roots, the total dry mass and root biomass, nitrogen content in biomass and roots, the crude protein content in biomass and roots, the accumulation of nitrogen in the biomass of shoots and roots, harvest index, physiological efficiency, efficiency in production of tuberous roots, the recovery efficiency of the utilization efficiency nitrogen, starch content, the starch and yield of ethanol. All clones in this study reached values higher than the national average yield of root yield (11,84 Mg ha-1). The productivity of the aboveground biomass of clones, respond to levels above the levels of nitrogen applied in the present study. A dose of approximately 130 kg ha-1 nitrogen provides maximum yields of total productivity of the tuberous roots of sweet potato clones. The physiological efficiency of recovery of nitrogen applied to the N utilization and efficiency of storage root production decreased with increasing doses of N applied to all sweet potato clones evaluated, whereas the accumulation of N in shoots and tuberous roots of clones IPB-149 and IPB-075 showed significant increases. The dose of 154 kg ha-1 N promotes greater production of total dry matter in storage roots of sweet potato clones. Clone sweet potato IPB-149 showed higher correlation between the use of nitrogen and root yield. With a dose between 120 and 210 kg ha-1 of nitrogen as urea can obtain maximum yields of starch and ethanol in the culture of sweet potato. / Devido à necessidade de definir uma dose de nitrogênio agronômica e economicamente adequada para a cultura da batata-doce no estado de Sergipe. O objetivo deste estudo foi avaliar a produtividade de raízes tuberosas, amido e etanol em clones de batata-doce, analisadas a partir de doses de nitrogênio. O trabalho foi conduzido, entre os meses de março e agosto de 2012, na Fazenda Experimental Campus Rural da UFS , localizado no município de São Cristóvão, Sergipe, Brasil. Foi utilizado o delineamento experimental de blocos casualizados, em esquema fatorial 5x3, com três repetições, testando cinco doses de N (0; 30; 60; 120 e 240 kg ha-1), empregando-se como fonte de N a ureia (45% N), e três clones de batata-doce (Brazlândia Branca; IPB-075 e IPB-149). A cultivar comercial Brazlândia Branca foi considerada como testemunha. A colheita foi realizada aos 150 dias após o plantio, quantificando-se a produtividade total de biomassa e raízes, o teor de matéria seca das raízes, a massa seca total de biomassa e raízes, o teor de nitrogênio na biomassa e nas raízes, o teor de proteína bruta na biomassa e nas raízes, o acúmulo de nitrogênio na biomassa da parte aérea e nas raízes, o índice de colheita, a eficiência fisiológica, a eficiência na produção de raízes tuberosas, a eficiência de recuperação, a eficiência de utilização do nitrogênio, o teor de amido, o rendimento de amido e de etanol. Todos os clones avaliados neste estudo alcançaram valores superiores ao rendimento médio nacional de produtividade de raízes tuberosas (11,84 Mg ha-1). A produtividade da biomassa da parte aérea dos clones avaliados, respondem a níveis acima das doses de nitrogênio aplicadas no presente estudo. A dose de aproximadamente 130 kg ha-1 de nitrogênio proporciona rendimentos máximos de produtividade total de raízes tuberosas pelos clones de batata-doce. A eficiência fisiológica, de recuperação do nitrogênio aplicado, a de utilização do N e a eficiência de produção de raízes tuberosas diminuíram com o aumento das doses de N aplicadas, para todos os clones de batata-doce avaliados, enquanto que, o acúmulo de N na parte aérea e nas raízes tuberosas dos clones IPB-075 e IPB-149 apresentaram incrementos significativos. A dose de 154 kg ha-1 de N favorece a maior produção de massa seca total de raízes tuberosas nos clones de batatadoce. O clone de batata-doce IPB-149 proporcionou maior correlação entre o uso de nitrogênio e a produtividade de raízes. Com a dose entre 120 e 210 kg ha-1 de nitrogênio na forma de ureia pode-se obter rendimentos máximos de amido e de etanol na cultura da batatadoce.

O presente trabalho foi realizado objetivando avaliar o desempenho, característica de carcaça e análise econômica de cordeiros Santa Inês confinados alimentados com silagens de forrageiras alternativas. Foram utilizados quinze cordeiros da raça Santa Inês com idade média de três meses, não castrados e com peso vivo médio inicial de 18,7 ± 5,8 kg, sendo distribuídos aleatoriamente em seus respectivos tratamentos, os quais foram: silagem de milho (SM); silagem de Capim-elefante com 15% de fubá de milho (SC); silagem de parte aérea de batata com 15% de fubá de milho (SRB). Isto é, três tratamentos com cinco repetições, dispostos em um delineamento em bloco completamente casualizado. Observou-se que os animais alimentados com silagem de milho e com parte aérea de batata como fontes de volumosos tiveram os maiores ganhos de peso diário. Os animais que receberam como volumoso a silagem de milho apresentaram maiores valores de rendimento de carcaça quente e rendimento de carcaça fria, 45% e 44,40% respectivamente. Observou-se também, no presente trabalho, em valor absoluto, maior rendimento verdadeiro (55,06%) para os animais alimentados com silagem de milho devido a haver uma relação direta com maior peso absoluto de carcaça quente. Para os parâmetros econômicos da margem bruta e margem líquida pode se observar que o tratamento com silagem de parte aérea de batata apresentou os melhores resultados, embora negativos. O comprometimento da receita com alimentação foi menor no tratamento com parte aérea de batata. A parte aérea de batata e o capim-elefante proporcionam bons resultados em termos de desempenho, características de carcaça e cortes cárneos.

O presente trabalho foi realizado objetivando avaliar a qualidade das silagens de forrageiras tropicais e sua influência no desempenho de cordeiros da raça Santa Inês, manejados em sistema de confinamento. Foram utilizados cordeiros da raça Santa Inês, não castrados, distribuídos aleatoriamente em seus respectivos tratamentos, os quais foram: silagem de milho (SM); silagem de Capim-elefante com 15% de fubá de milho (SC); silagem de parte aérea de batata doce com 15% de fubá de milho (SPAB). Dispostos em delineamento em bloco casualizado com cinco repetições. As análises de matéria seca, nitrogênio amoniacal e pH não apresentaram diferenças estatísticas entre os tratamentos, porém para as demais análises de PB, CZ, CNF, FDN, FDA, entre outras, houve diferença (P<0,05) entre os tratamentos. Resultados esses que não modificam a qualidade das silagens, apenas, apresentando diferenças diante das suas características particulares. Observou-se também que os animais alimentados com silagem de milho, silagem da parte aérea da batata doce e a silagem com capim elefante apresentaram igualdade quanto as variáveis de desempenho, como: ganho de peso total, ganho médio diário, conversão alimentar, consumo de matéria seca e de fibras em detergente neutro (kg/dia e g/kg0,75), entretanto as únicas diferenças observadas foram relacionadas ao consumo de matéria seca em % PV que foram superiores no tratamento com a silagem de batata doce, não apresentando diferença na silagem de milho e na silagem de capim elefante. O consumo de fibras em detergente neutro (%PV) apresentou diferença entre as silagens de milho e da parte aérea da batata doce, no entanto, a silagem de capim elefante apresentou igualdade para ambos tratamentos. Permitindo concluir que as silagens de capim elefante, parte aérea da batata doce e de milho apresentaram bons resultados nos seus respectivos teores bromatologico, podendo ser utilizadas sem na alimentação de cordeiros da raça Santa Inês. / The present study was performed to evaluate the quality of silages of tropical forages and its influence on the performance of lambs Santa Inês, handled in feedlot. Were used lambs Santa Inês, not castrated, randomly distributed in their respective treatments, which were corn silage (SM); Elephant grass silage with 15% of corn (SC); silage shoots sweet potato with 15% of corn (SPAB). Arranged in a randomized block design with five replication. Analyses of dry matter, ammonia nitrogen and pH did not differ among treatments, but for the remaining analyzes of CP, CZ, NFC, NDF, ADF, among others, significant differences (P <0.05) between treatments. Results that do not change the quality of the silage, only with differences on their particular characteristics. It was also observed that animals fed corn silage, silage of shoots and sweet potato with elephant grass silage showed equal as the performance variables, such as total weight gain, average daily gain, feed conversion, dry matter intake and neutral detergent fiber (kg /day and PV0,75). However the only differences were related to the consumption of dry matter in % BW which were higher in the treatment with the sweet potato silage, no difference in corn silage and elephant grass silage.The use of neutral detergent fiber (% PV) showed differences between corn silage and shoots of sweet potatoes, however, the elephant grass silage showed equal for both treatments. Allowing us to conclude that the silage shoots sweet potato, elephant grass and corn showed good results in their respective bromatological levels and can be used without impairing the performance of Santa Inês lambs.

PhD (Agric) (Food Science and Technology) / Department Food Science and Technology / In recent years, there has been a lot of interest in orange fleshed sweet potato (OFSP) [Ipomoea batatas (L.) Lam] cultivar, as a cheaper source of vitamin A. In Southern Africa, reports have shown that one in every three children has deficiency in vitamin A. This study investigated the variations in β-carotene (vitamin A precursor) content among selected OFSP cultivars grown in Limpopo Province, South Africa. In addition, the study investigated the effects of location on functional properties, total carotenoids and antioxidant profile of the sweet potato flour as well as their physicochemical, functional and nutritional properties. Four (4) sweet potato cultivars [Dagga, Bophelo, Impilo (orange fleshed) and Mvuvhelo (cream fleshed)] were obtained from two locations, namely, University of Venda (Univen) agricultural experimental farm and Tshiombo irrigation scheme (Tshiombo) and analysed for pasting, functional, physicochemical and nutritional properties. The sweet potato flours from these two locations were also analysed by computed tomographic (CT) scans for flour particle density. Mineral and microstructure of OFSP flours were analysed by scanning electron microscope (SEM). All measurements, except the tristimulus L* a* b* and other colour parameters from five replicates, were performed in triplicate. Statistical analysis was performed using a one-way analysis of variance and means were separated using Duncan’s multiple range test; P < 0.05 was considered to be statistically significant. Pearson’s correlation coefficients were used to determine the correlation among functional, physicochemical, nutritional and pasting properties of sweet potato flour. β-carotene content varied significantly between the two locations from 70.98 ± 0.8 μg/g (Tshiombo) to 86.09 ± 2.0 μg/g (Univen), among cultivars from 1.71 ± 0.0 μg/g (Mvuvhelo) to 201.50 ± 1.0 μg/g (Dagga) and among orange fleshed (Dagga, Bophelo and Impilo) flours from 28.38 ± 0.2 μg/g (Impilo) to 201.50 ± 1.0 μg/g (Dagga). There was a similar trend in the contents of α-carotene to that of β-carotene from the two locations, which ranged from 0.63 ± 0.0 mol/L (Tshiombo) to 1.01 ± 0.0 mol/L (Univen). Mvuvhelo had significantly the lowest α-carotene content (0.50 ± 0.0 mol/L) and Impilo the highest (1.28 ± 0.0 mol/L). The total carotenoids was highest for Impilo (7.56 μg/g) and lowest for Mvuvhelo (1.33 ± 0.1 μg/g) but did not vary significantly (P > 0.05) between ii the locations. The antioxidant activity, based on 2, 2-diphenyl-1picrylhydrazyl (DPPH) free radical scavenging activity, was significantly highest in Bophelo (63.37 ± 0.8 mMAAE ml-1) and lowest in Dagga (26.93 ± 1.4 mMAAE ml-1) flours. The ferric reducing antioxidant power (FRAP) varied significantly across the locations and among the cultivars and ranged from 14.45 ± 0.3 μMTE ml-1 (Tshiombo) to 17.40 ± 1.1 μMTE ml-1 (Univen). FRAP was significantly highest in Impilo (21.12 ± 2.1 μMTE ml-1) and lowest in Mvuvhelo (8.16 ± 2.0 μMTE ml-1). Total carotenoid content positively correlated with DPPH (0.486*), FRAP (0.830**), β-carotene (0.370*), and α-carotene (0.424*). The antioxidant content and the radical scavenging activity were significantly correlated (0.563**). Vitamin A content was significantly lowest (6.88 ± 0.38 μg/g retinol) in Dagga flour and highest (7.97 ± 0.25 μg/g) in Impilo flour. Protein content varied significantly across the two locations and ranged from 4.23% (Tshiombo) to 7.16% (Univen). Dagga had significantly the lowest (3.47%) protein content while Impilo had the highest (7.53%). The fat content of the flours varied significantly between the two locations ranging from 0.63% (Tshiombo) to 1.01% (Univen). The protein content was positively correlated 0.594** and 0.421* to vitamin A and fat contents respectively. The Bophelo colour luminosity was significantly lower (L* 76.2) than the other two OFSP, Dagga (L* 83.51) and Impilo (L* 82.07). Bophelo a* (14.09) also differed significantly across all sweet potato cultivars. All cultivars differed significantly in b* values. Colour intensity (ΔE*) ranged from 15.87 to 38.48 for Mvuvhelo and Bophelo, respectively. Chroma ranged from 87.52 to 84.95 for Dagga and Mvuvhelo respectively. Total starch content was significantly different in all sweet potato cultivars and ranged from 244.07 μg/100 g (Bophelo) to 325.04 mg/g (Dagga). Resistant starch differed significantly in all sweet potato cultivars ranging from 1.21 μg/100 g dwb (Bophelo) to 7.07 μg/100 g dwb (Impilo). Ash content was significantly different in all cultivars and ranged from 3.17% (Dagga) to 3.79% (Bophelo). Water holding capacity (WHC) varied significantly across the two locations and ranged from 1.44 g H2O/g DM (Tshiombo) to 1.72 g H2O/g DM (Univen). Bophelo had significantly the lowest (1.27 g H2O/g DM) WHC and Impilo the highest (1.99 g H2O/g DM). The ash content negatively correlated to total starch (-0.928**) but positively iii correlated to WHC (0.654**). Peak viscosity differed significantly across all cultivars under study and ranged from 126.54 RVU (Bophelo) to 302.36 RVU. (Dagga). There was significant difference in trough viscosity across all cultivars ranging from 55.97 RVU (Impilo) to 280.78 RVU (Dagga). There were significant differences in the final viscosity across all cultivars ranging from 78.99 RVU (Impilo) to 319.26 (Dagga). Peak time viscosity varied significantly across all cultivars ranging from 3.87 min (Impilo) to 8.47 min. (Bophelo). Dagga cultivar had significantly the highest pasting temperature (94.16oC) and Bophelo the lowest (77.75oC). The setback viscosity was significantly highest 51.10 RVU (Mvuvhelo) and lowest 23.01 RVU (Impilo). All cultivars from the two locations consistently showed high potassium content ranging from 0.46% (Impilo) to 1.38% (Dagga) as compared to other minerals such as magnesium, calcium and chlorine which ranged from 0.16% (Impilo) to 0.34%. (Dagga). The CT scans revealed that there was a possibility of evaluating the effect of location on the density of granules of sweet potato flour and also the inherent differences in granular distribution of various sweet potato cultivars. SEM revealed high amounts of potassium, magnesium and chlorine. A profile of physicochemical and functional properties of flour of some of the OFSP cultivars produced in Limpopo province, South Africa has been drawn. This study also highlights the nutritional quality of the flour from four sweet potato cultivars and provides a ranking of flour to help the producers in the selection process. Bophelo flour was ranked the highest in terms of β- and, α-carotenes, total carotenoids and antioxidant capacity while Impilo was ranked highest in terms of functional properties and ash content. This study has highlighted significant differences in a number of parameters measured among the sweet potato cultivars. Therefore, in order to derive the maximum benefit from aIn recent years, there has been a lot of interest in orange fleshed sweet potato (OFSP) [Ipomoea batatas (L.) Lam] cultivar, as a cheaper source of vitamin A. In Southern Africa, reports have shown that one in every three children has deficiency in vitamin A. This study investigated the variations in β-carotene (vitamin A precursor) content among selected OFSP cultivars grown in Limpopo Province, South Africa. In addition, the study investigated the effects of location on functional properties, total carotenoids and antioxidant profile of the sweet potato flour as well as their physicochemical, functional and nutritional properties. Four (4) sweet potato cultivars [Dagga, Bophelo, Impilo (orange fleshed) and Mvuvhelo (cream fleshed)] were obtained from two locations, namely, University of Venda (Univen) agricultural experimental farm and Tshiombo irrigation scheme (Tshiombo) and analysed for pasting, functional, physicochemical and nutritional properties. The sweet potato flours from these two locations were also analysed by computed tomographic (CT) scans for flour particle density. Mineral and microstructure of OFSP flours were analysed by scanning electron microscope (SEM). All measurements, except the tristimulus L* a* b* and other colour parameters from five replicates, were performed in triplicate. Statistical analysis was performed using a one-way analysis of variance and means were separated using Duncan’s multiple range test; P < 0.05 was considered to be statistically significant. Pearson’s correlation coefficients were used to determine the correlation among functional, physicochemical, nutritional and pasting properties of sweet potato flour. β-carotene content varied significantly between the two locations from 70.98 ± 0.8 μg/g (Tshiombo) to 86.09 ± 2.0 μg/g (Univen), among cultivars from 1.71 ± 0.0 μg/g (Mvuvhelo) to 201.50 ± 1.0 μg/g (Dagga) and among orange fleshed (Dagga, Bophelo and Impilo) flours from 28.38 ± 0.2 μg/g (Impilo) to 201.50 ± 1.0 μg/g (Dagga). There was a similar trend in the contents of α-carotene to that of β-carotene from the two locations, which ranged from 0.63 ± 0.0 mol/L (Tshiombo) to 1.01 ± 0.0 mol/L (Univen). Mvuvhelo had significantly the lowest α-carotene content (0.50 ± 0.0 mol/L) and Impilo the highest (1.28 ± 0.0 mol/L). The total carotenoids was highest for Impilo (7.56 μg/g) and lowest for Mvuvhelo (1.33 ± 0.1 μg/g) but did not vary significantly (P > 0.05) between ii the locations. The antioxidant activity, based on 2, 2-diphenyl-1picrylhydrazyl (DPPH) free radical scavenging activity, was significantly highest in Bophelo (63.37 ± 0.8 mMAAE ml-1) and lowest in Dagga (26.93 ± 1.4 mMAAE ml-1) flours. The ferric reducing antioxidant power (FRAP) varied significantly across the locations and among the cultivars and ranged from 14.45 ± 0.3 μMTE ml-1 (Tshiombo) to 17.40 ± 1.1 μMTE ml-1 (Univen). FRAP was significantly highest in Impilo (21.12 ± 2.1 μMTE ml-1) and lowest in Mvuvhelo (8.16 ± 2.0 μMTE ml-1). Total carotenoid content positively correlated with DPPH (0.486*), FRAP (0.830**), β-carotene (0.370*), and α-carotene (0.424*). The antioxidant content and the radical scavenging activity were significantly correlated (0.563**). Vitamin A content was significantly lowest (6.88 ± 0.38 μg/g retinol) in Dagga flour and highest (7.97 ± 0.25 μg/g) in Impilo flour. Protein content varied significantly across the two locations and ranged from 4.23% (Tshiombo) to 7.16% (Univen). Dagga had significantly the lowest (3.47%) protein content while Impilo had the highest (7.53%). The fat content of the flours varied significantly between the two locations ranging from 0.63% (Tshiombo) to 1.01% (Univen). The protein content was positively correlated 0.594** and 0.421* to vitamin A and fat contents respectively. The Bophelo colour luminosity was significantly lower (L* 76.2) than the other two OFSP, Dagga (L* 83.51) and Impilo (L* 82.07). Bophelo a* (14.09) also differed significantly across all sweet potato cultivars. All cultivars differed significantly in b* values. Colour intensity (ΔE*) ranged from 15.87 to 38.48 for Mvuvhelo and Bophelo, respectively. Chroma ranged from 87.52 to 84.95 for Dagga and Mvuvhelo respectively. Total starch content was significantly different in all sweet potato cultivars and ranged from 244.07 μg/100 g (Bophelo) to 325.04 mg/g (Dagga). Resistant starch differed significantly in all sweet potato cultivars ranging from 1.21 μg/100 g dwb (Bophelo) to 7.07 μg/100 g dwb (Impilo). Ash content was significantly different in all cultivars and ranged from 3.17% (Dagga) to 3.79% (Bophelo). Water holding capacity (WHC) varied significantly across the two locations and ranged from 1.44 g H2O/g DM (Tshiombo) to 1.72 g H2O/g DM (Univen). Bophelo had significantly the lowest (1.27 g H2O/g DM) WHC and Impilo the highest (1.99 g H2O/g DM). The ash content negatively correlated to total starch (-0.928**) but positively iii correlated to WHC (0.654**). Peak viscosity differed significantly across all cultivars under study and ranged from 126.54 RVU (Bophelo) to 302.36 RVU. (Dagga). There was significant difference in trough viscosity across all cultivars ranging from 55.97 RVU (Impilo) to 280.78 RVU (Dagga). There were significant differences in the final viscosity across all cultivars ranging from 78.99 RVU (Impilo) to 319.26 (Dagga). Peak time viscosity varied significantly across all cultivars ranging from 3.87 min (Impilo) to 8.47 min. (Bophelo). Dagga cultivar had significantly the highest pasting temperature (94.16oC) and Bophelo the lowest (77.75oC). The setback viscosity was significantly highest 51.10 RVU (Mvuvhelo) and lowest 23.01 RVU (Impilo). All cultivars from the two locations consistently showed high potassium content ranging from 0.46% (Impilo) to 1.38% (Dagga) as compared to other minerals such as magnesium, calcium and chlorine which ranged from 0.16% (Impilo) to 0.34%. (Dagga). The CT scans revealed that there was a possibility of evaluating the effect of location on the density of granules of sweet potato flour and also the inherent differences in granular distribution of various sweet potato cultivars. SEM revealed high amounts of potassium, magnesium and chlorine. A profile of physicochemical and functional properties of flour of some of the OFSP cultivars produced in Limpopo province, South Africa has been drawn. This study also highlights the nutritional quality of the flour from four sweet potato cultivars and provides a ranking of flour to help the producers in the selection process. Bophelo flour was ranked the highest in terms of β- and, α-carotenes, total carotenoids and antioxidant capacity while Impilo was ranked highest in terms of functional properties and ash content. This study has highlighted significant differences in a number of parameters measured among the sweet potato cultivars. Therefore, in order to derive the maximum benefit from a given cultivar careful selection of sweet potato cultivars would be necessary.

Thesis (M. Sc. (Plant Protection)) -- University of Limpopo, 2021 / Worldwide, root-knot (Meloidogyne species) nematodes are considered to be the most important and damaging genus in crop husbandry. The existence of a wide host range, over 2000 plants, and several biological races, makes the management of this nematode genus difficult with nematode-resistant crop Hybrid Sorghum Sudan grass (Sorghum bicolor × Sorghum Sundanese) has been classified as being resistant to certain Meloidogyne species and races, with a wide range of uses in crop rotation intended to manage nematode population densities. However, due to the ability of nematodes to enter chemiobiosis when gradually exposed to chemicals, this hybrid might not be effective in managing nematode population densities for the subsequent highly susceptible sweet potato (Ipomoea batatas L.) cultivars. The objective of the study was to determine whether hybrid Sorghum-Sudan grass would suppress M. javanica (Trial 1), M. incognita race 2 (Trial 2) and M. incognita race 4 (Trial 3) population densities, allowing a nematode susceptible sweet potato cv. ′Beauregard′ as successor crop to be cultivated without suffering nematode damage. The hybrid Sorghum-Sudan grass study was conducted under greenhouse conditions, with seven inoculation levels, namely, 0; 5; 25; 125; 625; 3 125 and 15 625 eggs and second-stage juveniles (J2) of each nematode species or race, arranged in randomised complete block design, with six replications and validated in time. Plant growth, foliar nutrient elements and nematodes were collected at 56 days after inoculation and prepared for analysis using standard methods. The reproductive factor (RF) at all levels was zero, whereas nematode inoculation at all levels did not have any effect on plant growth of the hybrid Sorghum-Sudan grass. However, the nematode levels affected the accumulation of nutrient elements and the quality of forage. After cultivating the susceptible sweet potato cultivar in pots xxx previously with hybrid Sorghum-Sudan grass at increasing levels of M. javanica alone, that is in Trial 1, similar results were observed with respect to RF and lack of nematode damage to plant growth. Consequently, the hybrid was suitable for use in crop rotation with sweet potato for the purpose of managing nematode population densities of thermophilic Meloidogyne species and/or races. / National Research Foundation of South Africa (NRF) and the Agricultural Research Council (ARC)

Sweet potato is a popular food security crop in South Africa and has a considerable commercial value. Fusarium wilt (FW), caused by the fungal pathogen Fusarium oxysporum formae speciales (f. sp.) batatas, has been reported worldwide and is widespread in sweet potato production areas in South Africa. Preliminary molecular identification of South African isolates from diseased sweet potato plants indicated that there are other formae speciales besides F. oxysporum f. sp. batatas associated with FW. The objectives of the study were to conduct a field survey and to characterise the isolates of the Fusarium oxysporum species complex (FOSC) using phylogenetic analyses, morphological characterisation and DNA barcoding. Phylogenetic analyses revealed two other formae speciales, namely F. oxysporum f. sp. tuberosi and F. oxysporum f. sp. vanillae that were associated with FW. This study has contributed in understanding and knowledge of FOSC associated with FW of sweet potato in South Africa. / Life and Consumer Sciences / M. Sc. (Life Sciences)

MSCAGR (Agricultural Economics) / Department of Agricultural Economics / This research aimed to assess the profitability of sweet potato production enterprises. The focus areas were on: determining differences in profitability of different sweet potato enterprises located in different villages; identifying factors that affect the profitability of sweet potato enterprises; determining differences in the sweet potato markets; and identifying marketing channels utilised by sweet potato enterprises. The study was carried out in 8 villages in Makhado and Thulamela local municipalities of the Vhembe district of Limpopo province. There were 78 sweet potato farmers identified and interviewed as respondents in the study. A gross margin analysis model was used to calculate the profitability of sweet potato enterprises, while a multiple regression model was adopted to analyse factors that affect profitability of sweet potato enterprises. The study revealed the domination of females in sweet potato production, wherein 69.2% of the respondents were females. Furthermore, the study revealed that 16.7% of the respondents were illiterate, 24% of the respondents had never received any form of agricultural training. The findings of the study revealed that sweet potato production is a viable and profitable enterprise in the study area. Farmers recorded an average gross margin of R11 329.94 per ha. Furthermore, labour cost and fertilizer cost accounted for the highest costs incurred in production contributing 45% and 32% respectively to total costs. The results of the study further revealed that six variables were statistically significant to profitability. Occupation status, farming experience, unpaid family members, and labour cost were statistically significant to profitability at the 1% level of significance; whereas tractor hire cost and chemical cost were statistically significant to profitability at the 5% level of significance. The study recommends that stakeholders involved in agriculture and community development should attend to issues such agro-processing trainings and extension services offered to the farmers in the Vhembe district.