Pediococcus cerevisiae, Lactobacillus casei, Lactobacillus plantarum, Leuconostoc mesenteroides, Lactococcus diacetylactis Bifidobacterium bifidum, Leuconostoc oenos, and mixed cultures of Propionibacterium shermanii and P. cerevisiae were used to ferment cucumber juice brine (CJB) at 22-26°C for 1.5 months. Sugar utilization ranged from 14.6 to 86.1%. pH of the fermented CJB ranged from 3.24 to 4.12 and titratable acidity ranged from 0.30 to 0.93%. All strains tested degraded malic acid and citric acid. Leu. mesenteroides and Leu. oenos did not utilize citric acid for diacetyl-acetoin production. The concentration of acetic, propionic and lactic acids varied among the fermentation treatments. The heterofermenters produced high concentrations of CO₂, ethanol and mannitol and CJB with high volatile/nonvolatile acid ratios. The fermentation balance indicated that sugars had been used to produce compounds not measured in this study. Twelve aroma and six flavor by mouth descriptors were used to describe flavor of the final products in the trained panel descriptive analysis. Sourness intensity was the only sensory descriptor that correlated with the chemical analysis data. The intensities of seven aroma and three flavor by mouth descriptors were significantly different (p < 0.05) among treatments. Aroma preference mean scores from 9-point hedonic scale ranged from 4.69-5.39; they were not significantly different (p > 0.05). Formation and Potential Industrial Applications of An Insoluble Polyelectrolyte Complex: Chitosan-Polyacrylic Acid Chitosan and polyacrylic acid mixtures were prepared in different mole ratios and at different ionic strengths (0.025-0.300). No insoluble complex formation at pH=2 was detected. In the 3 to 6 pH range, the maximum complex formation occurred at different mole ratios. The complex composition is affected by pH but not by ionic strength. An electrostatic interaction between -COO⁻ and -NH₃+ groups was involved in complex formation. This study suggests that process recommendations for industrial application of chitosan as a coagulating agent can be made based on the ionic strength, pH and charge group concentration of the fluid to be treated. / Graduation date: 1990

Pectinmethylesterase (PME) activity in fresh cucumber fruit was determined. The effects of several cationic species, temperature, pH, and acetic acid on the activity of cucumber PME was investigated. The efficacy of blanching, infiltration with CaCl₂ or acetic acid, and fermentation with 0 and 40 mM CaCl₂ on inhibition of cucumber PME activity were evaluated. Over 50% of PME activity was present in the skin and 75% occurred within the outer 3 mm of the fruit. Maximum stimulation of PME occurred at 125 mM NaCl, 200 mM KCl, and 5 mM CaCl₂. Higher levels of each cation demonstrated inhibition of PME activity. 50% inhibition was observed at 750 mM NaCl, 800 mM KCl, and 200 mM CaCl₂. Optimum pH was 8.0 and acid pH conditions greatly reduced activity. PME exhibited no activity at pH 4.0. PME activity responded typically to temperature variations with maximum activity occurring at 50°C. The temperature coefficient Q¹⁰ for PME activity between 10 and 40°C was 1.24. PME activity was slightly stimulated by increased levels of acetic acid and reached its maximum at 1.5% acetic acid at pH 7.5. No inhibitory effect on PME was detected at acetic acid levels of 0 to 2.0%. Inhibition of PME by NaCl and CaCl₂ was reversible. High levels of NaCl (1 M) stabilized PME activity while incubation of PME activity in low levels of NaCl (0.24 M) resulted in loss of activity over time. Both high (500 mM) and low (5 mM) levels of CaCl₂ imparted stability to PME activity. No detectable PME activity remained in cucumbers after 15 days of fermentation. Addition of CaCl2 (40 mM equilibrated) to the fermentation brine caused a rapid reduction in PME activity during the first 6 to 12 hours after brining. After 24 hours of brining there was no difference in PME activity due to CaCl₂ addition. Acetic acid infiltration at high levels (>10%) effectively reduced the pH of skin tissue to near 4 and resulted in complete inhibition of PME activity. The most effective treatment for controlling cucumber PME activity was rapid pH reduction by acetic acid infiltration and resulting in PME inhibition. Infiltration with very high CaCl₂ levels (>500 mM) may also be beneficial toward accomplishing PME inhibition. Rapid inactivation prior to brining or within 6 to 12 hours after brining is necessary to achieve effective control of cucumber PME activity. / Graduation date: 1989

No description available.

No description available.

Thesis (M.Sc.). / Written for the Dept. of Plant Science. Title from title page of PDF (viewed 2008/01/15). Includes bibliographical references.

Presented as Thesis (Ph. D.)--University of Wisconsin--Madison, 1927. / Reprinted from American journal of botany, vol. XVI, no. 2 (Feb. 1929). Includes bibliographical references (p. 84-85).

Presented as Thesis (Ph. D.)--University of Wisconsin--Madison, 1917. / Reprinted from Journal of agricultural research, vol. XV, no. 3 (21 Oct. 1918). Contribution from Bureau of Plant Industry (G--160). "Literature cited": p. 220.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1949. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 113-115).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1964. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1963. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 67-70).