Thesis (M.Sc.)(Microbiology)--University of Pretoria, 2007. / Includes summary. Includes bibliographical references. Available on the Internet via the World Wide Web.

Made available in DSpace on 2014-06-11T19:24:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-03-16Bitstream added on 2014-06-13T20:52:24Z : No. of bitstreams: 1 pigoli_dr_me_botfca.pdf: 396943 bytes, checksum: 2e66219ce3bec5e15ceae5c7e492e2bd (MD5) / Universidade Estadual Paulista (UNESP) / As hortaliças apresentam propriedades nutricionais importantes para alimentação humana, principalmente devido à riqueza em vitaminas, minerais e fibras. No entanto, durante o processo de cocção das hortaliças ocorrem perdas de nutrientes, diminuindo a qualidade do alimento a ser consumido. O objetivo desse trabalho foi verificar o método e o tempo de cozimento mais adequado para o preparo de partes convencionais e não convencionais de quatro hortaliças, visando minimizar as perdas nutricionais. As hortaliças utilizadas foram: abóbora (polpa e casca), cenoura (polpa e casca), brócolis (flor, folha e talo) e couve flor (flor, talo e folha). Essas hortaliças foram submetidas a pré testes de cozimentos, iniciando-se com 0,5 min, 1 min, 1,5 min e sucessivamente. No pré teste foi observado a textura do alimento, para que todas as espécies obtivessem a mesma textura independente do tipo de cozimento. O grau de maciez foi avaliado subjetivamente por pressão das hortaliças entre os dedos, alcançando uma consistência adequada ao consumo. As hortaliças foram submetidas a quatro tipos de tratamentos térmicos (pressão, imersão, micro-ondas e vapor), após foram trituradas com um mix doméstico e armazenadas à -18 ºC. Foram realizadas análises físico químicas (proteínas, lipídios, fibras, açúcares redutores e totais e ácido ascórbico) e minerais (ferro, zinco, magnésio, potássio, fósforo e cálcio). Nas condições em que o experimento foi realizado, os resultados permitiram concluir que o método de cozimento à vapor e em micro-ondas obtiveram menores perdas nutricionais, pelo fato das hortaliças não entrarem em contato direto com à água no momento do cozimento, as partes não convencionais das hortaliças estudadas possuem quantidades equivalentes ou superiores de nutrientes e minerais, quando comparadas as partes convencionais das hortaliças estudadas / The vegetables provide important nutritional properties for human consumption, mainly due to the wealth of vitamins, minerals and fiber. However, during the cooking process of vegetable nutrient losses occur, reducing the quality of the food to be consumed. The aim of this study was to verify the method and cooking time most suitable for the preparation of conventional and unconventional shares of four vegetables; to minimize nutrient losses. The vegetables used were: pumpkin pulp and peel; carrot pulp and peel; broccoli flower, leaf and stem; and cauliflower flower, stem and leaf. These vegetables were subjected to pre cooking tests was iniciating with 0.5 min, 1 min, 1,5 min and successively. Pretest was observed in the texture of the food, so that all species to obtain the same texture independent of the type of cooking. The degree of softening was evaluated subjectively by pressure of greenery between the toes, reaching a consistance adequated by consume. The vegetables were subjected to four types of heat treatment (pressure, immersion, microwave and steam), after been pounded with a mix household and stored at -18 ºC. Physic chemistries analyzes were performed (proteins, lipids, and total reducing sugars and ascorbic acid) and minerals (iron, calcium, zinc, magnesium, potassium, phosphorus and calcium). In the conditions of this experiment, the results showed that the method of steaming and microwave had lower nutritional losses, because the vegetables do not come into direct contact with the water when cooking, unconventional parts of vegetables studied have equivalent or higher amounts of nutrients and minerals, when compared to the conventional share of the vegetables studie

7 p. / Grafting cucurbits onto rootstocks resistant to diseases and abiotic stresses can be a methodto overcome limited availability of effective pre-plant fumigants or land to rotate and to allowearlier planting. Commonly used rootstocks for cucurbits have resistance to Fusarium (race1&2) as well as cold tolerance, among other favorable traits like increased vigor of the scion. Grafting of cucurbits was developed in Asia primarily to allow production without rotation, because arable land is so limited. In the US, crop rotation schedules for seedless watermelon can be 3 years or longer reducing the amount of watermelon a grower can produce in a season. We have been growing grafted and non-grafted seedless watermelon on the same field/plot for 4 years, with no fumigation or off-season rotation of other crops. During the last 2 years, we planted early (March 1) to determine if grafting could overcome low night temperatures in addition to disease pressures. Treatments included grafted and non-grafted plants, covering with frost protection and non-covered. The results of the last 2 years indicate that grafted plants yielded nearly twice as much as non-grafted plants, suggesting that grafting can be a promising technology for Arizona watermelon producers.

Content and availability of nutrients in four vegetable protein supplements (palm kernel, soybean, cottonseed and rapeseed meals) were determined using growing chicks. Average availability of sixteen amino acids in these feedstuffs ranged from 84.5% (palm kernel meal) to 97.3% (soybean meal). Palm kernel meal was lowest and soybean meal highest in content of essential amino acids. Results of mineral availability (calcium, phosphorus, magnesium, manganese, zinc and copper) indicated high content and availability of calcium, phosphorus and magnesium; low content and availability of zinc and copper. Average availability of minerals varied from 50.0% (palm kernel meal) to 74.3% (soybean meal). Among mineral elements tested, phosphorus (78.0%) and calcium (72.6%) showed the highest availability while zinc (44.0%) was least available. Crude fibre and phytic acid were implicated as factors depressing availability of minerals tested. Crude fibre content was inversely related to availability of all six minerals tested while phytic acid content significantly (P^O.01) affected availability of phosphorus, calcium, zinc and magnesium. Metabolizable energy (ME) of the feedstuffs determined using three week old broiler chicks, ranged from 1957 kcal/kg dry matter (rapeseed meal) to 2796 kcal/kg dry matter (palm kernel meal). Chemical constituents, available carbohydrate and metabolizable energy content of seven different rapeseed meals were determined. Metabolizable energy values ranged from 1492 kcal/kg (Span A) to 1957 kcal/kg (commercial RSM). Of all chemical constituents tested, ether extract, sugar and starch content were most significantly (P«%0.01) related to metabolizable energy and were incorporated into equations to predict ME of rapeseed meal from their chemical constituents. Content and availability of six minerals (Ca, P, Mg, Mn, Zn, Cu) were determined using the test rapeseed meals. Samples were high in calcium, phosphorus and magnesium and low in copper in comparison to other vegetable protein supplements. Average availability of minerals ranged from 52.2% (Span A) to 64.0% (commercial RSM). Among minerals tested, phosphorus (75.3%), copper (74.3%) and calcium (68.0%) showed the highest availabilities. Zinc was least available (44.1%). Treatment of palm kernel meal with 3%, 5% or 7% NaOH in an attempt to delignify the material and improve its nutritive value, caused a reduction in protein, acid detergent fibre and acid detergent lignin content of the meal. There was considerable amino acid destruction, the extent being directly related to the severity of the alkali treatment. Incorporation of alkali-treated meal -at 30% level into broiler starter rations depressed growth rate and feed efficiency of chicks. Inclusion of palm kernel meal at 10%, 20% or 30% into a standard broiler starter diet significantly (P«»0.05) increased average daily gain of chicks over controls. Highest growth rate and feed efficiency were observed in chicks on the 10% PKM ration. Increased level of PKM incorporation slightly depressed feed efficiency but not growth rate of chicks. The need for increased utilization of vegetable protein supplements in chick rations especially in the developing countries was discussed. / Land and Food Systems, Faculty of / Graduate

Sadie Lucile Cooper / Typescript / M.S. Florida State College for Women 1916 / Includes bibliographical references

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