Dissertation (PhD)--University of Stellenbosch, 2008. / Bibliography. Also available via the Internet.

Thesis (Ph.D.)--Princeton university, 1916. / Published also without thesis note. Digitization funded by NEH digital to microfilm conversion project. Title selected from the series Literature of the agricultural sciences for the Core historical literature of agriculture, Agricultural economics and rural sociology. Also available in print and in microfilm.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1923. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 262-263).

Orientador: Hilary Castle de Menezes / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-03T16:29:46Z (GMT). No. of bitstreams: 1 CastilloCaceres_Miluska_M.pdf: 10593950 bytes, checksum: b93ec4104306167339ca2e01eb59d1ff (MD5) Previous issue date: 2003 / Resumo: Existe dentro do setor de sucos de frutas e drinques uma importância crescente na produção de produtos diferenciados. O desenvolvimento de "blends" entre diferentes sucos e polpas é um recurso a disposição da indústria para o preparo de bebidas diferenciadas. O objetivo deste trabalho foi desenvolver e avaliar sensorialmente um "blend" a base da polpa de tamarindo (Tamarindus indica L) e suco de beterraba (Seta vulgaris) e ainda estudar o processo de extração da polpa de tamarindo. Desta maneira, foram avaliados através de diversos ensaios, condições adequadas para a extração da polpa de tamarindo. Os resultados indicaram que à temperatura de 50 ac, tempo de maceração de 20 min e uma relação fruta:água de 1:1,5, foram as melhores condições para obter um produto com características físico-químicas e microbiológicas adequadas para ser utilizada como matéria-prima na formulação do "blend" tamarindo-beterraba. Produziu-se polpa de tamarindo e suco de beterraba para formular onze diferentes misturas, para o qual foi utilizado um planejamento experimental completo do tipo fatorial 22. Estas formulações foram avaliadas sensorialmente mediante teste de aceitabilidade e intenção de compra utilizando uma escala hedônica não estruturada de nove pontos. Determinou-se que a formulação do "blend" constituída de 35% de polpa de tamarindo e 20% de suco de beterraba foi a que apresentou maior aceitação e evidenciou uma maior intenção de compra. O "blend" avaliado como próximo do ideal apresentou características físico-químicas e microbiológicas estáveis ao longo de 90 dias de estocagem a temperatura ambiente / Abstract: Currently, increasing importance is being given to the production of differentiated products within the fruit juice and drinks sector. The development of different juice and pulp blends is one resource available to industry for the preparation of differentiated beverages. The objective of this research was the development and sensory evaluation of a juice blend based on tamarind (Tamarindus indica) pulp and beetroot (Beta vulgaris) juice. A study was also carried out to determine the best processing conditions to extract the tamarind pulp. Thus various trials were carried out for the extraction of the tamarind pulp and the results indicated that a temperature of 50QC, maceration time of 20 min. and a fruit : water ratio of 1:1.5 produced a pulp with adequate physical, chemical and microbiological characteristics to be used as a raw material for the tamarind-beetroot blend. Tamarind pulp and beetroot juice were produced in amounts sufficient to formulate the 11 juice blends determined by the 22 complete, factorial, experimental design. These formulations were evaluated by a sensory acceptance test and buying intention using a 9 point non-structured hedonic scale. The results showed that the blend formulated with 35% tamarind pulp and 20% beetroot juice was the most accepted blend with the greatest buying intention. This blend was shown to be microbiologically, physically and chemically stable for 90 days of storage at room temperature / Mestrado / Tecnologia de Alimentos / Mestre em Tecnologia de Alimentos

The main objective of this study was to determine the effect of fruit ripeness and drying method on the oxidative stability and micro-component content of avocado oil extracted with supercritical carbon dioxide (SC-CO2). A secondary objective was to determine the effect of fruit ripeness, method of fruit drying and extraction method on the extractability of avocado oil with hexane and SC-CO2. For the oil extractability study, unripe and ripe avocado fruit pieces were either freeze-dried or oven-dried (80oC) and extracted with hexane or SC-CO2. For both extraction methods, oil yield was higher from ripe fruit than from unripe fruit. Scanning electron microscopy (SEM) indicated structural degradation during ripening, making the oil more available for extraction in ripe fruit. Oil from freeze-dried samples was in most cases more extractable than from oven-dried samples possibly through formation of rigid structures due to starch gelatinisation and dehydration and protein crosslinking around the oil cells during oven drying. Oil yield was higher with hexane than with SC-CO2 extraction because hexane is less selective, permeates the whole plant material and leads to a more complete extraction, while SC-CO2 may create paths of least resistance in the plant material where it moves preferentially, thus leading to a less complete extraction. For oxidative stability studies and micro-component characterisation, oil extractions were performed on an industrial scale SC-CO2. extractor. For all treatments (unripe freeze-dried, ripe freeze-dried, unripe oven-dried, ripe oven-dried), oil was divided into four fractions and analysed for fatty acid profile, peroxide value (PV), anisidine value (AV), free fatty acids (FFA), oxidative stability index (OSI), colour, tocopherol, sterol, chlorophyll, carotenoid and total unsaponifiable content. Oil from ripe, freeze-dried avocado had relatively lower levels of chlorophyll, carotenoids and tocopherols, than oil samples from the other treatments. This may be due to relatively higher lipoxygenase levels in ripe fruit which may bring about higher oxidative breakdown of these components. Also, the activity of lipoxygenase may be preserved under the lower temperature conditions of freeze-drying, but inactivated at high temperature during oven-drying. Intensity of blue and red on the Lovibond colour scale of all oil samples as well as chlorophyll and carotenoid content increased with progressive extraction. These pigments are presumably extracted in the latter stages of extraction because they are located in chloroplasts, chromoplasts and idioblast cells with thicker membranes than the parenchyma cells where triglycerides are located. Levels of total sterols, total tocopherols and their isomers did not show any specific trends with progressive extraction, which could be related to their location in cell membranes where they would be extracted concurrently with the triglycerides. Levels of total unsaponifiables were mostly higher in the first than the latter fractions. This could be due to the early elution of non-polar waxes which are highly soluble in SC-CO2 and highly available due to their location on the surface of the avocado skin. The fatty acid profile of the avocado oil was not influenced by the degree of ripeness or drying method and therefore did not affect the OSI. Oleic acid increased while linoleic acid decreased with progressive extraction. Compared to the changes observed in levels of some of the micro-components, the changes in fatty acid levels with progressive extraction were relatively small and the fatty acid profile alone could not explain the OSI of the oil. Oil from oven-dried avocado had lower PVs but higher AVs than oil from freeze-dried fruit indicating more advanced oxidative deterioration in oil from oven-dried samples than from freeze-dried samples. FFA levels were higher in oil from ripe, freeze-dried fruit. Levels of hydrolytic enzymes increase during fruit ripening and are preserved during freeze-drying while they are inactivated during oven-drying. FFA levels decreased with progressive extraction. Free fatty acids are very soluble in the SC-CO2 and due to their location on the surface of the plant material, they could be extracted early in the extraction. Oil from oven-dried fruit had relatively higher OSI compared to the other treatments. The OSI of all samples increased with progressive extraction. There was a significant negative correlation between FFA and OSI for both drying methods. AV correlated positively with OSI for oil from oven-dried fruit and negatively for oil from freeze-dried fruit. AV contributed the most to the prediction of OSI in oven-dried fruit, while FFA contributed the most in freeze-dried fruit. It was suggested that the high OSI of oil from oven-dried fruit, despite its high AV, may be due to the presence of compounds with high antioxidant activity in the oil formed through the high temperatures of the oven-drying process. Therefore, using multiple regression techniques, predictive models were developed to determine the effect of the micro-components on the oxidative stability of the oil. The OSI correlated positively with chlorophyll (0.83) and carotenoids (0.80). The models indicated that chlorophyll and carotenoids were the most important variables in predicting the oxidative stability of avocado oil extracted with SC-CO2. This might be due to the antioxidant effect of carotenoids and the possible formation of pheophytin and pyropheophytin, thermal breakdown products of chlorophyll, which exert antioxidant effects in oil. / Thesis (PhD (Food Science))--University of Pretoria, 2008. / Food Science / unrestricted

This study analyses the adoption of some innovations by Okanagan Valley orchardists. Comparisons were made with findings on the adoption of innovations by American farmers. Also included in the study is an evaluation of the 1964 televised chautauqua produced by the Horticultural Branch of the British Columbia Department of Agriculture. This style of chautauqua (which may be defined as an assembly for educational purposes, lectures, entertainment, etc.) replaced an earlier version held in district halls throughout the Okanagan Valley. The data were gathered by interviewing a sample of Okanagan Valley orchardists from the population of orchardists in the area served by the 1964 T.V. Chautauqua and who were also included in the 1960 Orchard Survey of the Okanagan Valley. Generally, adoption theory, as developed from studies in other countries, can be applied to a specific Canadian setting. Earlier adopters of innovations were more active educationally, had been in orcharding longer, had larger and more valuable orchards, and sold more orchard products than later adopters. These results coincide with past studies. However, the vast majority of the early adopters were full-time orchardists, while other studies have found part-time farmers to be the most innovative. Also, this study found complete ownership of the farm to be a characteristic of the later adopters while other studies have found this characteristic of early adopters. Two differences with previous studies were found in the use of sources of information. Agricultural agencies increased in importance between the awareness and interest stages in the adoption process. Also unique to this study was less use of mass media and agricultural agencies by the earlier adopters than the later ones. Evidence of a two-step concept of the diffusion of technological innovations was found with innovations flowing from their place of origin to the earlier adopters and from them to the later adopters. Innovativeness was found to be a general characteristic of certain respondents in that they adopted most innovations. The T.V. Chautauqua was more valuable than its predecessor in one respect; more of the laggards (who use fewer agricultural agencies than most orchardists) watched the televised program than attended the district hall chautauqua. This study is limited by the use of a sample to gather data, the use of an incomplete population list for sampling and inconsistencies in the interpretation of questions and answers by the interviewers. / Land and Food Systems, Faculty of / Graduate

Ph.D. (Biochemistry) / This study consistsof two parts namely: • Phosphoproteins in ripening mango fruit tissue: Effect of y-irradiation and various effectors on protein phosphorylation during the climacteric rise, climacteric peak and post-climacteric stages of ripening. • Protein kinase (EC 2.7.10 and EC 2.7.11) activities in ripening mango fruit tissue: Classification, purification and characterisation.

A total of seven anthocyanin pigments were observed in both paper and thin layer chromatograms of the fresh and freeze-dried compressed samples stored for O month whereas the freeze-dried compressed samples stored at 70 F and 100 F for 6 months showed the retention of three to six pigments. All of those seven pigments were unstable and cyanidin-3- (2G- xylosylrutinoside) was the least stable pigment. The separation of anthocyanina by disc gel electrophoresis was studied for the first time. Disc electropherograms of fresh and freeze-dried com-pressed sour cherries stored at O month revealed the presence of eight bands whereas the freeze-dried compressed sour cherries stored at 70 F and 100 F for 6 months showed the retention of three to four bands. In further study, this technique could be helpful for the separation of anthocyanins in other fruits. The study indicated that the fresh samples had anthocyanin content higher than those of the freeze-dried compressed samples stored at 70 F and 100 F for 6 months and also showed that the degradation of anthocyanins is greater at the higher storage temperature with longer storage periods.

The thesis examines land-use changes in a selected area of the Niagara Fruit Belt between 1954 and 1978. Part of the former township of Louth was chosen for investigation because it is located in the centre of the fruit belt, and is an area affected by several urban influences. Two detailed land-use maps were produced from aerial photograph interpretation. These maps reveal the many exchanges among agricultural land uses and the actual loss to urban and urban-related uses which occurred during the time span investigated. They indicate the loss of fruit land to non-agricultural uses is less than was anticipated. Increases in grape acreages have been implemented relatively close to the city of St. Catharines and the lost peach acreage is not entirely due to urbanization. A land-use change index was developed, based on total change per lot, for use in the quantitative analysis. The 1954 assessment roll provided the data on individual properties. Eight hypotheses were developed to account for the land-use changes. These were rejected, and it was suggested that the study area was undergoing a "normal” process of change, resulting from a combination of agricultural and urban forces. Further research is needed in order to understand more fully, the processes of land-use change in an area such as Louth. / Thesis / Master of Science (MS)

The purposes of this study are (1) to determine the ascorbic acid content of a variety of fruit juices available in Denton, Texas, during March to July, 1943; (2) to ascertain the loss of ascorbic acid when canned grapefruit, orange, pineapple, and apple juices are opened and stored in the home refrigerator for several days' use; and (3) by means of data obtained, to make recommendations as to the most advantageous ways of using one's "points" in purchasing canned fruit juices for their ascorbic acid value.