Cranberries are processed mainly for the production of jelly, sauce and juice. The content of pectic substances in the cranberry gives the fruit a desirable property for processing such products. Pectic enzymes which catalyze the hydrolysis of pectic substances may affect the consistency of these products. The concern of this study was to isolate and characterize the pectic enzymes that may be found in the cranberry fruit. The methods utilized in the preparation of enzyme extracts were by (1) the preparation of acetone powder (2) the preparation of acetone powder in the presence of polyethylene glycol and (3) by extraction in the presence of polyvinylpyrrolidone. The following conclusions were made: (1) Cranberry protein extracts were found to exhibit polygalacturonase activity. (2) The cranberry polygalacturonase extract obtained by the use of polyethylene glycol exhibited a 40.3 percent loss in viscosity over one percent pectave solution in citrate buffer at pH 5.0 and 30°C during the initial hour of the reaction. A 22.1 and 8.6 percent loss in viscosity was found when the polyvinylpyrrolidone extract and the acetone powder extract were used as the source of enzyme respectively. (3) Cranberry polygalacturonase may be classified as an endo- type polygalacturonase which catalyzes a random hydrolysis of both low and high methoxyl pectic substances. (4) Maximum activity of the cranberry polygalacturonase was found to be at pH 5.0. (5) Sodium chloride concentration up to 0.6 M showed no significant effect on the polygalacturonase activity in a citrate buffer at pH 5.0. (6) The cranberry polygalacturonase was inactivated when exposed to 100°C for 35 minutes at pH 5.0. (7) Cranberry proteins were found to possess low pectin esterase activity. Optimum activity of cranberry pectin esterase occurred at pH 7.5 with sodium chloride concentration at 0.15M. (8) Cranberry pectin esterase was inactivated when exposed to 100°C for five minutes. / Graduation date: 1968

Due to the scarcity of information concerning the oxidase systems in cranberries the peroxidase, catalase, and polyphenolase systems, which are used as biochemical indexes of adequacy for enzyme inactivation in other fruits and vegetables, were investigated. Enzyme extracts were prepared from acetone powders with and without phenol-binding agents such as polyethylene glycol and polyvinylpyrrolidone (PVP) and buffered PVP. The acetone-PVP combination was found to be the most effective in reducing the polyphenolic content of the enzyme extract. Highest specific activity was obtained by using a buffered PVP extract. The pH optimum of cranberry peroxidase activity is 6.0. Heat inactivation of cranberry peroxidase was determined to follow first order kinetics. There was 90% destruction at 70, 80, and 90°C requiring 9.40, 1.60, and 0.47 minutes of heat treatment, respectively. The activation energy for the thermal inactivation of cranberry peroxidase was found to be 37.2 kcal/mole. Guaicol, o-phenylene diamine (OPDA), and pyrogallol were tested for their sensitivity to cranberry peroxidase with OPDA determined as most sensitive. The pH optimum for catalase activity was found to range from 7.5 to 9.2. Kinetics for the heat inactivation of cranberry catalase was determined not to be of the first order nor zero order. Approximately 50% of the catalase activity is inactivated after heating for 17, 1.8, and O.6 minutes at temperatures of 50, 60, and 70°C, respectively. Cranberry polyphenolase activity was measured using catechol as a substrate. The product of the reaction absorped maximally at 400 mu. The pH optimum for cranberry polyphenolase activity was determined to be 7.0. Heat inactivation of cranberry polyphenolase was found to follow first order kinetics. There was 90% destruction at 50, 60, and 70°C requiring 15.85, 7.05, and 1.37 minutes of heat treatment, respectively. The activation energy for the inactivation of cranberry polyphenolase was found to be 27.7 kcal/mole. / Graduation date: 1969

Thesis (Ph. D.)--University of Wisconsin--Madison, 2001. / Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--George Washington University, 1906. / "Issued October 10, 1907." Includes bibliographical references (p. 55-57) and index.

Thesis (Ph. D.)--University of Wisconsin--Madison, 2004. / Includes bibliographical references. Also available on the Internet.

Thesis (M.S.)--University of Wisconsin--Madison, 1982. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 95-97).

Thesis (Ph. D.)--George Washington University, 1906. / "Issued October 10, 1907." Includes bibliographical references (p. 55-57) and index.

Thesis (Ph. D.)--University of Wisconsin--Madison, 2004. / Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1980. / Typescript. Vita. Description based on print version record. Includes bibliographical references (leaves 107-111).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1991. / Vita. Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.