No description available.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 64-68). Also available via the Internet.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 95-103). Also available via the Internet.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1940. / Typescript. Includes abstract and vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 39-43).

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.

Respiration rates of developing muskmelon (Cucumis melo L.) seeds were determined polarographically using a Clark-type O₂ electrode (Hansatech LD2). Seeds were obtained from fruits harvested 20, 30, 40, and 50 days after anthesis (DAA). Respiration (O₂ uptake) was measured for fresh intact seeds and fresh dissected seeds. The respiration rate of intact seeds declined from a maximum of 2.28 μmol O₂/min/g DWT at 20 DAA to a minimum of 0.16 μmol O₂/min/g DWT at 50 DAA. Dissecting intact seeds into embryo, testae, and perisperm tissues increased the respiration rate of 20 DAA seeds to 3.12 μmol O₂/min/g DWT but had no effect on more mature seeds. Respiration rate was highly correlated with seed relative growth rate and water content. Respiration rate was not consistently changed after incubation in water. This indicates that respiration rate is not directly controlled by subtle variations in water content. Rather, seed respiration rate is directly linked with turgor-driven, expansive growth and relative growth rate. Fifty-DAA seeds from dry storage were imbibed on water saturated blotters, and respiration rates of whole seeds, decoated seeds, and embryos were compared. Respiration during imbibition was not significantly inhibited by the testae or perisperm tissue. In addition, 50-DAA dried, imbibed seeds were subjected to reduced O₂ concentrations ranging from 3.5 kPa partial pressure O₂ (pO₂) to 21 kPa pO₂. Respiration was not limited by O₂ until pO₂ was reduced to approximately 5 kPa, indicating a high affinity for O₂. Gas chromatography revealed that pO₂ in the seed cavity of muskmelon fruits ranged from 12.5 to 8 kPa. Fifty-DAA seeds from dry storage were imbibed on polyethylene glycol (PEG), mannitol, or NaCl ranging from -0.5 to -2.5 MPa water-potential or on abscisic acid (ABA) solutions ranging in concentration from 10 to 50 μM. Respiration and solution water-potential were measured at 10-hr intervals. At 10 hr of imbibition, each type of osmoticum and ABA stimulated respiration to values greater than for seeds imbibed in pure water. Beyond 10 hr, respiration rates were variable. / Master of Science

No description available.

No description available.

Fresh ripe, cantaloupes were processed into juice and juice concentrate. Processing trials were conducted on fresh and frozen fruits with and without rind. The effects of maceration enzymes and fining agents on yield and quality were investigated. Compositional measurement included °Brix, pH, titratable acidity, formol values, ascorbic acid content, total carotenoids, sugar and nonvolatile acid profiles, browning indices and Hunter color parameters. Considerable ascorbic acid degradation occurred during processing. The high juice yield (80%) and low acidity suggest its potential use as an alternate sweetener source. Sensory evaluation by a trained panel showed that concentrating the juice samples from flesh and rind can remove the rind aroma and flavor characteristics. Juices obtained from flesh and from flesh and rind were not significantly different (p [less than or equal to] 0.05) except for overall intensity and fresh fruit flavor characters. Single strength juice was significantly different (p [less than or equal to] 0.05) from concentrate on most aroma and flavor characters. / Graduation date: 1991