No description available.

No description available.

Graduation date: 1972

The effect of frozen storage time on the composition of the cell wall polysaccharide (CWP) of muskmelon (Cucumis melo) cultivars at different stages of maturity was investigated. Changes in composition, firmness, drip loss, and color of Cantaloupe and Honey Dew melon flesh were determined at three stages of maturity and for three periods of storage at -23°C. Relationships between firmness, drip loss, and other composition measurements, as well as the total CWP sugar composition, were also determined. Cell wall polyssacharides were isolated and purified, and fractionations were performed using cyclohexane trans- 1,2-diamine tetraacetate (CDTA), Na₂C0₃, guanidinium thiocyanate (GTC), and KOH. All fractions and residues were dialysed and then freeze-dried. Following hydrolysis of CWP fractions with trifluoroacetate (TFA), the alditol acetate derivatives of neutral sugars from each CWP fraction were prepared and analyzed by gas chromatography, using myo-inositol as the internal standard. TFA insoluble fractions were analyzed colorimetrically using phenol-sulphuric acid reagent. Uronic acid was determined using 0.15% m-hydroxybiphenyl for absorbance at 520 nm with galacturonic acid as the standard. It was determined that CDTA and Na₂C0₃ fractions were composed of typical pectic materials, containing mostly galacturonic acid with the neutral sugars arabinose, galactose, rhamnose, and a smaller amount of xylose. As maturity increased, CDTA fraction yields increased, though total neutral sugar CWP compositions decreased. GTC and KOH fractions were typical of hemicellulose, and contained principally xylose, glucose, galactose, mannose, and fucose, with very small amounts of uronic acid, arabinose, and rhamnose. Residue fractions contained principally glucose and galactose, with smaller amounts of mannose, xylose, arabinose, and fucose. With the exception of xylose and glucose, all neutral sugars decreased significantly (p < 0.01) as maturity increased in both the Cantaloupe and Honey Dew melons. Total uronic acid did not change as maturity increased, except for Cantaloupe, where total uronic acid decreased from the ripe to overripe stages. The CDTA fraction yield increased and all neutral sugars decreased significantly (p < 0.05) as storage time was increased. Only the CDTA fraction yield was negatively correlated with the firmness of both melons, and was positively correlated with drip loss as maturity and frozen storage time were increased. Firmness was positively correlated with Na₂C0₃ and GTC fraction yield in Cantaloupe, whereas for Honey Dew there was no correlation between firmness and Na₂C0₃ or GTC fraction yield as maturity increased. The KOH fraction was negatively correlated with firmness in Cantaloupe, whereas there was no correlation between firmness and KOH fractions in Honey Dew existed as maturity increased. The residue fractions increased in both melons only from the underripe to the ripe stages, and did not change from ripe to overripe. Firmness was positively correlated with total rhamnose, arabinose, mannose, and galactose as maturity increased, and the drip loss was negatively correlated with all total neutral sugars as storage time was increased. During frozen storage, there was a significant decreases (p < 0.05) in total CWP sugars in relation to increased storage time. The decrease in total sugars was more dramatic during the 0 to 5 month period than the 5 to 10 month period of frozen storage. Galactose did not change in the Cantaloupe, whereas in Honey Dew it decreased 34.3% from 0 to 5 months then decreased only 13% from 5 to 10 months of storage. / Graduation date: 1994

No description available.

No description available.

No description available.

M.Sc. / Bananas are climacteric fruit which are characterised by a low rate of ethylene production and respiration during the pre-climacteric phase, followed by a sudden burst in ethylene production and respiration during ripening. Ethylene is a gaseous plant hormone that accelerates the ripening of climacteric fruit. In order to extend the shelf life of bananas the action or synthesis of ethylene must be inhibited or delayed. Examples of such inhibitors are 1- methylcyclopropene (1-MCP) an inhibitor of ethylene action, and aminoethoxyvinylglycine (AVG), an inhibitor of ethylene synthesis. The purpose of this research was to compare the effect of these two inhibitors on ripening of bananas. 1-MCP acts by blocking the ethylene receptors permanently. The results of this study indicated that 500 nL.L-1 1-MCP is more effective in delaying ripening of banana than AVG, although AVG delivered a better quality fruit in terms of colour. To be effective, bananas must be pre-treated with 1-MCP before they exposed to ethylene. The results also indicated that, the effectiveness 1-MCP to delay ripening decreases with storage time. The results show that ethylene binding to its membrane bound receptors is reversible if the exposure time to ethylene is less than 8 hours. Exposure to ethylene for 8 hours or more results in irreversible binding. However, binding only becomes permanent when exposure to ethylene exceeds 16 hours. For this reason treatment with 1-MCP becomes ineffective after exposure to ethylene for 24 hours due to the fact that ethylene has bound irreversibly and permanently to its binding sites and cannot be displaced by 1-MCP.

Made available in DSpace on 2014-06-11T19:22:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-06-20Bitstream added on 2014-06-13T18:48:47Z : No. of bitstreams: 1 leite_ghp_me_botfca.pdf: 653749 bytes, checksum: d0d894254b462b26f17369f46012f018 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O projeto de pesquisa teve por objetivo avaliar as alterações fisiológicas na cana-de-açúcar decorrente da aplicação de maturadores químicos com diferentes mecanismos de ação e os reflexos na produtividade e qualidade tecnológica. Dessa forma foram instalados e conduzidos dois experimentos em cana soca nas Fazendas São Joaquim e Bosque, situadas no município de Igaraçú do Tietê, Estado de São Paulo, pertencentes ao Grupo COSAN - Unidade Barra (Usina da Barra). O delineamento experimental utilizado foi o em blocos casualizados com cinco repetições. No experimento 1 (Fazenda São Joaquim) utilizou-se a variedade de cana-de-açúcar RB855453 e no Experimento 2 (Fazenda Bosque) a variedade SP80-3280. Os tratamentos consistiram na aplicação de sete maturadores químicos (KNO3 (p.c. Krista Kana), Etil-trinexapac (p.c. Moddus), Sulfometuron metil (p.c. Curavial), Etefon (p.c. Ethrel), KNO3 + boro (p.c. Krista Kana Plus), Glifosato (p.c. Roundup) e Compostos de radicais carboxílicos orgânicos + Glifosato (p.c. MTD + Roundup)) e uma testemunha, maturação natural. As doses empregadas foram, respectivamente: 3 kg p.c. ha-1, 0,8 L p.c. ha-1, 20 g p.c. ha-1, 2 L p.c. ha-1, 3,0 kg p.c. ha-1, 0,4 L p.c. ha-1 e 1,0 L p.c. ha-1 + 0,15 L p.c. ha-1. A aplicação dos maturadores ocorreu nos meses de março (Experimento 1) e maio (Experimento 2) de 2004, utilizando-se equipamento costal pressurizado (CO2). As parcelas foram constituídas de 8 linhas de 10m de comprimento com espaçamento de 1,5m. Foram avaliados os seguintes parâmetros bioquímicos, biométricos e tecnológicos: atividade das enzimas invertases ácida solúvel e neutra em caldo de cana; altura de plantas, diâmetro dos colmos, número de colmos, rebrota, florescimento, chochamento, brotação lateral, produtividade de colmos e açúcar; pH, acidez, pol, pureza... / The purpose of research was to evaluate physiological alterations in sugarcane due to the application of chemical compounds with different actions and its reflects in the productivity and technological quality. Two experiments were carried out in ratoon cane in São Joaquim Farm and Bosque Farm, in Igaraçú do Tietê, São Paulo State, Brazil, belonging to Grupo COSAN - Unidade Barra (Usina da Barra). The experimental design used was random blocks with five repetitions. In experiment one (São Joaquim Farm) sigarcane RB855453 was used, and in experiment two (Bosque Farm) sugarcane SP80-3280. The treatments consisted of seven chemical compounds (potassium nitrate (trademark Krista Kana), Ethyl-trinexapac (trademark Moddus), Sulfometuron methil (trademark Curavial), Ethephon (trademark Ethrel), potassium nitrate + boron (trademark Krista Kana Plus), Glyphosate (trademark Roundup) and compounds of organic carboxilic radicals + Glyphosate (trademark MTD + Roundup)), and one control. The doses were, respectively: 3.0 kg ha-1 Potassium nitrate, 0.8 L ha-1 Ethyl-trinexapac, 20 g ha-1 Sulfometuron methil, 2.0 L ha-1 Ethephon, 3.0 kg ha-1 KNO3 + Boro, 0.4 L ha-1 Glyphosate, 1.0 L ha-1 Comp. carboxílicos + 0.15 ha-1 Glyphosate. The applications of chemicals were performed in March (Experiment one) and in May (Experiment two) in 2004, with constant spraying pressure... (Complete abstract, click electronic address below)

A dependable source of quality fish spawn is a fundamental prerequisite for fish culture development. This is especially important inasmuch as most of the cultivable species do not breed in confined waters. Also, sport fisheries are gaining greater popularity, and subsequently the fish supply is being taxed. Still another need for fish spawn is in the ever increasing demand for bait minnows. Also, the construction of more and more dams has resulted in insurmountable obstacles for ascending and descending fish, which may ultimately result in complete destruction of some fisheries. Thus some measure of artificial propagation will have to be taken to safegaurd our valuable fishery resources. A partial solution to this problem of supplementing natural propagation is that of inducing the fish to spawn artificially in the hatchery. A method of doing this is by stimulating fish to breed by the use of pituitary hormones. Those pituitary hormone-containing glands are often collected under a variety of field conditions which may involve considerable effort, time, and money. Therefore,, it was my objective in this study to develop a practical refined assay on hormones using as small an amount as possible of the crude extract of pituitary suspension, and to make it simple enough that every lay fisheries man ,dll be able to apply it, thus meeting his demand for quality fish eggs in his own hatchery when he needs it most.