The problem in green pea grading system by using brine
flotation is loss of some less mature peas (generally
regarded as higher in quality and price) in the sinker
fraction (lower quality). Green peas were sampled from the
production line as follows: (1) blanched but ungraded peas,
(2) floater fraction, and (3) sinker fraction. Peas from the
floater and sinker fractions were tested using the standard
brine flotation test (United States Standards for Grades of
Frozen Peas, 1959). Using sodium chloride salt brine as the
separation medium, the blanched but ungraded peas were used
to test the effect on percent floaters caused by: (1) change
in brine concentration, (2) change in brine temperature, (3)
change in pea temperature. Again, the blanched but ungraded
peas were used to test the effect of underskin air on percent floaters, using sucrose syrup as the separation
medium. The relationships between change in percent floater
peas and maturity of the floater and sinker fractions were
determined by using Alcohol Insoluble Solids (AIS) analysis
as the maturity reference method. The nature of problem was
identified, when a high percent (44.9%) U.S. Fancy grade
floaters was found in the sinker fraction from the factory.
The study showed that the percentage of floaters was
significantly (p=0.05) influenced by brine concentration,
brine temperature, pea temperature, and retention of air
under the skin of the peas. Regression analysis of the data
for the first three factors indicated that rate of change in
percent floaters was greatest with brine concentration, and
least with pea temperature. The change in maturity of
floater and sinker fractions as determined by AIS analysis
showed a close positive relationship between the change in
percent floaters produced by change in the treatment
conditions. Again, AIS results showed that residual
underskin air in the intact blanched peas significantly
affected the accurate separation by a false increase in
buoyancy of borderline maturity peas (AIS was in between
floater's and sinker's) in the flotation process. The
underskin air factor was the least important factor
affecting percent floaters when compared with the other
factors of brine concentration, brine temperature, and pea
temperature. / Graduation date: 1985
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/27281 |
| Date | 20 December 1984 |
| Creators | Chavasit, Visith |
| Contributors | Varseveld, George W. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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