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
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/26812 |
| Date | 22 January 1968 |
| Creators | Arakji, Omar Ahmed |
| Contributors | Yang, Ho-Ya, 1912- |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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